14df2826166f1339eb7ddf5c5c84565fccb794de8Shuxin Yang//===- Reassociate.cpp - Reassociate binary expressions -------------------===// 2fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 3b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// The LLVM Compiler Infrastructure 4b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// 54ee451de366474b9c228b4e5fa573795a715216dChris Lattner// This file is distributed under the University of Illinois Open Source 64ee451de366474b9c228b4e5fa573795a715216dChris Lattner// License. See LICENSE.TXT for details. 7fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 8b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell//===----------------------------------------------------------------------===// 94fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// 104fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// This pass reassociates commutative expressions in an order that is designed 119046193e557d559f45dc50df5e20b1fccc90b2acChris Lattner// to promote better constant propagation, GCSE, LICM, PRE, etc. 124fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// 134fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// For example: 4 + (x + 5) -> x + (4 + 5) 144fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// 154fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// In the implementation of this algorithm, constants are assigned rank = 0, 164fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// function arguments are rank = 1, and other values are assigned ranks 174fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// corresponding to the reverse post order traversal of current function 184fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// (starting at 2), which effectively gives values in deep loops higher rank 194fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// than values not in loops. 204fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner// 214fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner//===----------------------------------------------------------------------===// 224fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 2308b43921e18f314c4fd38049291d323830934c36Chris Lattner#define DEBUG_TYPE "reassociate" 244fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner#include "llvm/Transforms/Scalar.h" 25d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/DenseMap.h" 26d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/PostOrderIterator.h" 27d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/STLExtras.h" 28d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/SetVector.h" 29d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/Statistic.h" 30d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/Assembly/Writer.h" 310b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/Constants.h" 320b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/DerivedTypes.h" 330b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/Function.h" 340b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/IRBuilder.h" 350b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/Instructions.h" 360b8c9a80f20772c3793201ab5b251d3520b9cea3Chandler Carruth#include "llvm/IR/IntrinsicInst.h" 374fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner#include "llvm/Pass.h" 384fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner#include "llvm/Support/CFG.h" 39551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/Debug.h" 40d3c7b7359d4992b9ab9f8e12ccd0a9b7d2446566Chris Lattner#include "llvm/Support/ValueHandle.h" 41bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner#include "llvm/Support/raw_ostream.h" 42d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/Transforms/Utils/Local.h" 43c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner#include <algorithm> 44d7456026629fc1760a45e6e955e9834246493147Chris Lattnerusing namespace llvm; 45d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 460e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumChanged, "Number of insts reassociated"); 470e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumAnnihil, "Number of expr tree annihilated"); 480e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumFactor , "Number of multiplies factored"); 49a92f696b74a99325026ebbdbffd2a44317e0c10bChris Lattner 500e5f499638c8d277b9dc4a4385712177c53b5681Chris Lattnernamespace { 513e8b6631e67e01e4960a7ba4668a50c596607473Chris Lattner struct ValueEntry { 52c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner unsigned Rank; 53c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner Value *Op; 54c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner ValueEntry(unsigned R, Value *O) : Rank(R), Op(O) {} 55c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner }; 56c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner inline bool operator<(const ValueEntry &LHS, const ValueEntry &RHS) { 57c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner return LHS.Rank > RHS.Rank; // Sort so that highest rank goes to start. 58c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } 59e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 60c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 6150cacb2a520b93530e79220a307c907163b9e370Devang Patel#ifndef NDEBUG 62e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// PrintOps - Print out the expression identified in the Ops list. 63e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// 649f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattnerstatic void PrintOps(Instruction *I, const SmallVectorImpl<ValueEntry> &Ops) { 65e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Module *M = I->getParent()->getParent()->getParent(); 66a1fa76cb5443e7b0fe7d36ee1118f80050e746f9David Greene dbgs() << Instruction::getOpcodeName(I->getOpcode()) << " " 671befe643b2a030f5e2433ce0034a27fb65b5f26bChris Lattner << *Ops[0].Op->getType() << '\t'; 687de3b5db26bb3c8dcca5348fb7c0be4f9bd1bcb7Chris Lattner for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 69a1fa76cb5443e7b0fe7d36ee1118f80050e746f9David Greene dbgs() << "[ "; 70a1fa76cb5443e7b0fe7d36ee1118f80050e746f9David Greene WriteAsOperand(dbgs(), Ops[i].Op, false, M); 71a1fa76cb5443e7b0fe7d36ee1118f80050e746f9David Greene dbgs() << ", #" << Ops[i].Rank << "] "; 727de3b5db26bb3c8dcca5348fb7c0be4f9bd1bcb7Chris Lattner } 73e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 7459500c8f9a76b3386329b6f837255c16f4e8b61bDevang Patel#endif 75e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 76844731a7f1909f55935e3514c9e713a62d67662eDan Gohmannamespace { 77464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth /// \brief Utility class representing a base and exponent pair which form one 78464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth /// factor of some product. 79464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth struct Factor { 80464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Value *Base; 81464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth unsigned Power; 82464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 83464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Factor(Value *Base, unsigned Power) : Base(Base), Power(Power) {} 84464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 85464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth /// \brief Sort factors by their Base. 86464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth struct BaseSorter { 87464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth bool operator()(const Factor &LHS, const Factor &RHS) { 88464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return LHS.Base < RHS.Base; 89464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 90464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth }; 91464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 92464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth /// \brief Compare factors for equal bases. 93464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth struct BaseEqual { 94464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth bool operator()(const Factor &LHS, const Factor &RHS) { 95464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return LHS.Base == RHS.Base; 96464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 97464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth }; 98464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 99464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth /// \brief Sort factors in descending order by their power. 100464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth struct PowerDescendingSorter { 101464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth bool operator()(const Factor &LHS, const Factor &RHS) { 102464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return LHS.Power > RHS.Power; 103464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 104464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth }; 105464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 106464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth /// \brief Compare factors for equal powers. 107464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth struct PowerEqual { 108464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth bool operator()(const Factor &LHS, const Factor &RHS) { 109464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return LHS.Power == RHS.Power; 110464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 111464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth }; 112464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth }; 1132d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 1142d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang /// Utility class representing a non-constant Xor-operand. We classify 1152d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang /// non-constant Xor-Operands into two categories: 1162d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang /// C1) The operand is in the form "X & C", where C is a constant and C != ~0 1172d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang /// C2) 1182d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang /// C2.1) The operand is in the form of "X | C", where C is a non-zero 1192d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang /// constant. 1202d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang /// C2.2) Any operand E which doesn't fall into C1 and C2.1, we view this 1212d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang /// operand as "E | 0" 1222d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang class XorOpnd { 1232d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang public: 1242d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang XorOpnd(Value *V); 1252d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 1262d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang bool isInvalid() const { return SymbolicPart == 0; } 1272d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang bool isOrExpr() const { return isOr; } 1282d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *getValue() const { return OrigVal; } 1292d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *getSymbolicPart() const { return SymbolicPart; } 1302d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang unsigned getSymbolicRank() const { return SymbolicRank; } 1312d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang const APInt &getConstPart() const { return ConstPart; } 1322d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 1332d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang void Invalidate() { SymbolicPart = OrigVal = 0; } 1342d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang void setSymbolicRank(unsigned R) { SymbolicRank = R; } 1352d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 1362d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Sort the XorOpnd-Pointer in ascending order of symbolic-value-rank. 1372d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // The purpose is twofold: 1382d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // 1) Cluster together the operands sharing the same symbolic-value. 1392d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // 2) Operand having smaller symbolic-value-rank is permuted earlier, which 1402d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // could potentially shorten crital path, and expose more loop-invariants. 1412d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Note that values' rank are basically defined in RPO order (FIXME). 1422d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // So, if Rank(X) < Rank(Y) < Rank(Z), it means X is defined earlier 1432d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // than Y which is defined earlier than Z. Permute "x | 1", "Y & 2", 1442d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // "z" in the order of X-Y-Z is better than any other orders. 1454fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang struct PtrSortFunctor { 1464fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang bool operator()(XorOpnd * const &LHS, XorOpnd * const &RHS) { 1474fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang return LHS->getSymbolicRank() < RHS->getSymbolicRank(); 1482d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 1492d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang }; 1502d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang private: 1512d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *OrigVal; 1522d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *SymbolicPart; 1532d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang APInt ConstPart; 1542d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang unsigned SymbolicRank; 1552d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang bool isOr; 1562d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang }; 157464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth} 158464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 159464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruthnamespace { 1603e8b6631e67e01e4960a7ba4668a50c596607473Chris Lattner class Reassociate : public FunctionPass { 161f55e7f54b1877aa6a58b368084cc25acbaa30967Chris Lattner DenseMap<BasicBlock*, unsigned> RankMap; 162f1d0f7781e766df878bec4e7977fa3204374f394Craig Topper DenseMap<AssertingVH<Value>, unsigned> ValueRankMap; 1634df2826166f1339eb7ddf5c5c84565fccb794de8Shuxin Yang SetVector<AssertingVH<Instruction> > RedoInsts; 164c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner bool MadeChange; 1654fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner public: 166ecd94c804a563f2a86572dcf1d2e81f397e19daaNick Lewycky static char ID; // Pass identification, replacement for typeid 167081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson Reassociate() : FunctionPass(ID) { 168081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson initializeReassociatePass(*PassRegistry::getPassRegistry()); 169081c34b725980f995be9080eaec24cd3dfaaf065Owen Anderson } 170794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel 1717e70829632f82de15db187845666aaca6e04b792Chris Lattner bool runOnFunction(Function &F); 1724fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 1734fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner virtual void getAnalysisUsage(AnalysisUsage &AU) const { 174cb2610ea037a17115ef3a01a6bdaab4e3cfdca27Chris Lattner AU.setPreservesCFG(); 1754fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner } 1764fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner private: 1777e70829632f82de15db187845666aaca6e04b792Chris Lattner void BuildRankMap(Function &F); 1784fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner unsigned getRank(Value *V); 179cd117f736c47947af5c6549734549e135e626c5cDuncan Sands void ReassociateExpression(BinaryOperator *I); 1800fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands void RewriteExprTree(BinaryOperator *I, SmallVectorImpl<ValueEntry> &Ops); 1819f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner Value *OptimizeExpression(BinaryOperator *I, 1829f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner SmallVectorImpl<ValueEntry> &Ops); 1839f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner Value *OptimizeAdd(Instruction *I, SmallVectorImpl<ValueEntry> &Ops); 1842d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *OptimizeXor(Instruction *I, SmallVectorImpl<ValueEntry> &Ops); 1852d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang bool CombineXorOpnd(Instruction *I, XorOpnd *Opnd1, APInt &ConstOpnd, 1862d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *&Res); 1872d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang bool CombineXorOpnd(Instruction *I, XorOpnd *Opnd1, XorOpnd *Opnd2, 1882d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang APInt &ConstOpnd, Value *&Res); 189464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth bool collectMultiplyFactors(SmallVectorImpl<ValueEntry> &Ops, 190464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVectorImpl<Factor> &Factors); 191464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Value *buildMinimalMultiplyDAG(IRBuilder<> &Builder, 192464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVectorImpl<Factor> &Factors); 193464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Value *OptimizeMul(BinaryOperator *I, SmallVectorImpl<ValueEntry> &Ops); 194e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *RemoveFactorFromExpression(Value *V, Value *Factor); 195841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands void EraseInst(Instruction *I); 196841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands void OptimizeInst(Instruction *I); 1974fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner }; 1984fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 1994fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 2002d1001064989b7fa79507816fc17d467fc00a2f2Shuxin YangXorOpnd::XorOpnd(Value *V) { 201ad26993e1a9b147c3ca4b170ab2eba260f89a1acShuxin Yang assert(!isa<ConstantInt>(V) && "No ConstantInt"); 2022d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang OrigVal = V; 2032d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Instruction *I = dyn_cast<Instruction>(V); 2042d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang SymbolicRank = 0; 2052d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 2062d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (I && (I->getOpcode() == Instruction::Or || 2072d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang I->getOpcode() == Instruction::And)) { 2082d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *V0 = I->getOperand(0); 2092d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *V1 = I->getOperand(1); 2102d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (isa<ConstantInt>(V0)) 2112d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang std::swap(V0, V1); 2122d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 2132d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (ConstantInt *C = dyn_cast<ConstantInt>(V1)) { 2142d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang ConstPart = C->getValue(); 2152d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang SymbolicPart = V0; 2162d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang isOr = (I->getOpcode() == Instruction::Or); 2172d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return; 2182d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 2192d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 2202d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 2212d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // view the operand as "V | 0" 2222d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang SymbolicPart = V; 2232d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang ConstPart = APInt::getNullValue(V->getType()->getIntegerBitWidth()); 2242d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang isOr = true; 2252d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang} 2262d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 227844731a7f1909f55935e3514c9e713a62d67662eDan Gohmanchar Reassociate::ID = 0; 228d13db2c59cc94162d6cf0a04187d408bfef6d4a7Owen AndersonINITIALIZE_PASS(Reassociate, "reassociate", 229ce665bd2e2b581ab0858d1afe359192bac96b868Owen Anderson "Reassociate expressions", false, false) 230844731a7f1909f55935e3514c9e713a62d67662eDan Gohman 231d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke// Public interface to the Reassociate pass 232d7456026629fc1760a45e6e955e9834246493147Chris LattnerFunctionPass *llvm::createReassociatePass() { return new Reassociate(); } 2334fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 2340fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// isReassociableOp - Return true if V is an instruction of the specified 2350fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// opcode and if it only has one use. 2360fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sandsstatic BinaryOperator *isReassociableOp(Value *V, unsigned Opcode) { 2370fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (V->hasOneUse() && isa<Instruction>(V) && 2380fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands cast<Instruction>(V)->getOpcode() == Opcode) 2390fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands return cast<BinaryOperator>(V); 2400fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands return 0; 2410fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands} 2420fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 2439c723199384b16899831937e2800d52f4f953569Chris Lattnerstatic bool isUnmovableInstruction(Instruction *I) { 244eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak switch (I->getOpcode()) { 245eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::PHI: 246eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::LandingPad: 247eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::Alloca: 248eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::Load: 249eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::Invoke: 250eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::UDiv: 251eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::SDiv: 252eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::FDiv: 253eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::URem: 254eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::SRem: 255eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::FRem: 2569c723199384b16899831937e2800d52f4f953569Chris Lattner return true; 257eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak case Instruction::Call: 258eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak return !isa<DbgInfoIntrinsic>(I); 259eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak default: 260eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak return false; 261eb0588b9920984fed0e6740a52d0e36feeaa9904Jakub Staszak } 2629c723199384b16899831937e2800d52f4f953569Chris Lattner} 2639c723199384b16899831937e2800d52f4f953569Chris Lattner 2647e70829632f82de15db187845666aaca6e04b792Chris Lattnervoid Reassociate::BuildRankMap(Function &F) { 2656007cb6c4d923e2dee4a1133fb6d1bb00a37062dChris Lattner unsigned i = 2; 266fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner 267fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner // Assign distinct ranks to function arguments 268e4d5c441e04bdc00ccf1804744af670655123b07Chris Lattner for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I) 269d3c7b7359d4992b9ab9f8e12ccd0a9b7d2446566Chris Lattner ValueRankMap[&*I] = ++i; 270fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner 2717e70829632f82de15db187845666aaca6e04b792Chris Lattner ReversePostOrderTraversal<Function*> RPOT(&F); 2724fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner for (ReversePostOrderTraversal<Function*>::rpo_iterator I = RPOT.begin(), 2739c723199384b16899831937e2800d52f4f953569Chris Lattner E = RPOT.end(); I != E; ++I) { 2749c723199384b16899831937e2800d52f4f953569Chris Lattner BasicBlock *BB = *I; 2759c723199384b16899831937e2800d52f4f953569Chris Lattner unsigned BBRank = RankMap[BB] = ++i << 16; 2769c723199384b16899831937e2800d52f4f953569Chris Lattner 2779c723199384b16899831937e2800d52f4f953569Chris Lattner // Walk the basic block, adding precomputed ranks for any instructions that 2789c723199384b16899831937e2800d52f4f953569Chris Lattner // we cannot move. This ensures that the ranks for these instructions are 2799c723199384b16899831937e2800d52f4f953569Chris Lattner // all different in the block. 2809c723199384b16899831937e2800d52f4f953569Chris Lattner for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 2819c723199384b16899831937e2800d52f4f953569Chris Lattner if (isUnmovableInstruction(I)) 282d3c7b7359d4992b9ab9f8e12ccd0a9b7d2446566Chris Lattner ValueRankMap[&*I] = ++BBRank; 2839c723199384b16899831937e2800d52f4f953569Chris Lattner } 2844fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 2854fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 2864fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattnerunsigned Reassociate::getRank(Value *V) { 28708b43921e18f314c4fd38049291d323830934c36Chris Lattner Instruction *I = dyn_cast<Instruction>(V); 288f55e7f54b1877aa6a58b368084cc25acbaa30967Chris Lattner if (I == 0) { 289f55e7f54b1877aa6a58b368084cc25acbaa30967Chris Lattner if (isa<Argument>(V)) return ValueRankMap[V]; // Function argument. 290f55e7f54b1877aa6a58b368084cc25acbaa30967Chris Lattner return 0; // Otherwise it's a global or constant, rank 0. 291f55e7f54b1877aa6a58b368084cc25acbaa30967Chris Lattner } 2924fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 293f55e7f54b1877aa6a58b368084cc25acbaa30967Chris Lattner if (unsigned Rank = ValueRankMap[I]) 294f55e7f54b1877aa6a58b368084cc25acbaa30967Chris Lattner return Rank; // Rank already known? 29500b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 29608b43921e18f314c4fd38049291d323830934c36Chris Lattner // If this is an expression, return the 1+MAX(rank(LHS), rank(RHS)) so that 29708b43921e18f314c4fd38049291d323830934c36Chris Lattner // we can reassociate expressions for code motion! Since we do not recurse 29808b43921e18f314c4fd38049291d323830934c36Chris Lattner // for PHI nodes, we cannot have infinite recursion here, because there 29908b43921e18f314c4fd38049291d323830934c36Chris Lattner // cannot be loops in the value graph that do not go through PHI nodes. 30008b43921e18f314c4fd38049291d323830934c36Chris Lattner unsigned Rank = 0, MaxRank = RankMap[I->getParent()]; 30108b43921e18f314c4fd38049291d323830934c36Chris Lattner for (unsigned i = 0, e = I->getNumOperands(); 30208b43921e18f314c4fd38049291d323830934c36Chris Lattner i != e && Rank != MaxRank; ++i) 30308b43921e18f314c4fd38049291d323830934c36Chris Lattner Rank = std::max(Rank, getRank(I->getOperand(i))); 30400b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 305cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner // If this is a not or neg instruction, do not count it for rank. This 306cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner // assures us that X and ~X will have the same rank. 307b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (!I->getType()->isIntegerTy() || 308fa82b6eba4e1584d7dba291c28fe908272e1e002Owen Anderson (!BinaryOperator::isNot(I) && !BinaryOperator::isNeg(I))) 309cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner ++Rank; 310cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner 311a1fa76cb5443e7b0fe7d36ee1118f80050e746f9David Greene //DEBUG(dbgs() << "Calculated Rank[" << V->getName() << "] = " 312bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner // << Rank << "\n"); 31300b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 314f55e7f54b1877aa6a58b368084cc25acbaa30967Chris Lattner return ValueRankMap[I] = Rank; 3154fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 3164fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 317f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner/// LowerNegateToMultiply - Replace 0-X with X*-1. 318f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner/// 319841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sandsstatic BinaryOperator *LowerNegateToMultiply(Instruction *Neg) { 320a7235ea7245028a0723e8ab7fd011386b3900777Owen Anderson Constant *Cst = Constant::getAllOnesValue(Neg->getType()); 321f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner 3220fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands BinaryOperator *Res = 3230fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands BinaryOperator::CreateMul(Neg->getOperand(1), Cst, "",Neg); 324841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Neg->setOperand(1, Constant::getNullValue(Neg->getType())); // Drop use of op. 3256934a04a8c15e9971cd1ea4d5c8df2d7afdd5be5Chris Lattner Res->takeName(Neg); 326f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner Neg->replaceAllUsesWith(Res); 3275367b23f76e75ebb680956575346fa8c3d56780fDevang Patel Res->setDebugLoc(Neg->getDebugLoc()); 328f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner return Res; 329f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner} 330f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner 331c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// CarmichaelShift - Returns k such that lambda(2^Bitwidth) = 2^k, where lambda 332c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// is the Carmichael function. This means that x^(2^k) === 1 mod 2^Bitwidth for 333c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// every odd x, i.e. x^(2^k) = 1 for every odd x in Bitwidth-bit arithmetic. 334c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// Note that 0 <= k < Bitwidth, and if Bitwidth > 3 then x^(2^k) = 0 for every 335c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// even x in Bitwidth-bit arithmetic. 336c038a7833565ecf92a699371d448135a097c9e2fDuncan Sandsstatic unsigned CarmichaelShift(unsigned Bitwidth) { 337c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (Bitwidth < 3) 338c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands return Bitwidth - 1; 339c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands return Bitwidth - 2; 340c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands} 341c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands 342c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// IncorporateWeight - Add the extra weight 'RHS' to the existing weight 'LHS', 343c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// reducing the combined weight using any special properties of the operation. 344c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// The existing weight LHS represents the computation X op X op ... op X where 345c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// X occurs LHS times. The combined weight represents X op X op ... op X with 346c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// X occurring LHS + RHS times. If op is "Xor" for example then the combined 347c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// operation is equivalent to X if LHS + RHS is odd, or 0 if LHS + RHS is even; 348c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// the routine returns 1 in LHS in the first case, and 0 in LHS in the second. 349c038a7833565ecf92a699371d448135a097c9e2fDuncan Sandsstatic void IncorporateWeight(APInt &LHS, const APInt &RHS, unsigned Opcode) { 350c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // If we were working with infinite precision arithmetic then the combined 351c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // weight would be LHS + RHS. But we are using finite precision arithmetic, 352c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // and the APInt sum LHS + RHS may not be correct if it wraps (it is correct 353c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // for nilpotent operations and addition, but not for idempotent operations 354c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // and multiplication), so it is important to correctly reduce the combined 355c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // weight back into range if wrapping would be wrong. 356c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands 357c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // If RHS is zero then the weight didn't change. 358c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (RHS.isMinValue()) 359c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands return; 360c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // If LHS is zero then the combined weight is RHS. 361c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (LHS.isMinValue()) { 362c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands LHS = RHS; 363c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands return; 364c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } 365c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // From this point on we know that neither LHS nor RHS is zero. 366c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands 367c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (Instruction::isIdempotent(Opcode)) { 368c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // Idempotent means X op X === X, so any non-zero weight is equivalent to a 369c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // weight of 1. Keeping weights at zero or one also means that wrapping is 370c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // not a problem. 371c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands assert(LHS == 1 && RHS == 1 && "Weights not reduced!"); 372c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands return; // Return a weight of 1. 373c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } 374c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (Instruction::isNilpotent(Opcode)) { 375c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // Nilpotent means X op X === 0, so reduce weights modulo 2. 376c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands assert(LHS == 1 && RHS == 1 && "Weights not reduced!"); 377c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands LHS = 0; // 1 + 1 === 0 modulo 2. 378c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands return; 379c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } 380c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (Opcode == Instruction::Add) { 381c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // TODO: Reduce the weight by exploiting nsw/nuw? 382c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands LHS += RHS; 383c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands return; 384c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } 385c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands 386c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands assert(Opcode == Instruction::Mul && "Unknown associative operation!"); 387c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands unsigned Bitwidth = LHS.getBitWidth(); 388c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // If CM is the Carmichael number then a weight W satisfying W >= CM+Bitwidth 389c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // can be replaced with W-CM. That's because x^W=x^(W-CM) for every Bitwidth 390c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // bit number x, since either x is odd in which case x^CM = 1, or x is even in 391c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // which case both x^W and x^(W - CM) are zero. By subtracting off multiples 392c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // of CM like this weights can always be reduced to the range [0, CM+Bitwidth) 393c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // which by a happy accident means that they can always be represented using 394c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // Bitwidth bits. 395c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // TODO: Reduce the weight by exploiting nsw/nuw? (Could do much better than 396c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // the Carmichael number). 397c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (Bitwidth > 3) { 398c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands /// CM - The value of Carmichael's lambda function. 399c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands APInt CM = APInt::getOneBitSet(Bitwidth, CarmichaelShift(Bitwidth)); 400c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // Any weight W >= Threshold can be replaced with W - CM. 401c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands APInt Threshold = CM + Bitwidth; 402c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands assert(LHS.ult(Threshold) && RHS.ult(Threshold) && "Weights not reduced!"); 403c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // For Bitwidth 4 or more the following sum does not overflow. 404c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands LHS += RHS; 405c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands while (LHS.uge(Threshold)) 406c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands LHS -= CM; 407c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } else { 408c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // To avoid problems with overflow do everything the same as above but using 409c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // a larger type. 410c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands unsigned CM = 1U << CarmichaelShift(Bitwidth); 411c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands unsigned Threshold = CM + Bitwidth; 412c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands assert(LHS.getZExtValue() < Threshold && RHS.getZExtValue() < Threshold && 413c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands "Weights not reduced!"); 414c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands unsigned Total = LHS.getZExtValue() + RHS.getZExtValue(); 415c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands while (Total >= Threshold) 416c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Total -= CM; 417c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands LHS = Total; 418c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } 419c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands} 420c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands 421c038a7833565ecf92a699371d448135a097c9e2fDuncan Sandstypedef std::pair<Value*, APInt> RepeatedValue; 422c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands 4230fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// LinearizeExprTree - Given an associative binary expression, return the leaf 424c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// nodes in Ops along with their weights (how many times the leaf occurs). The 425c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// original expression is the same as 426c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// (Ops[0].first op Ops[0].first op ... Ops[0].first) <- Ops[0].second times 427a94d6e87c4c49f2e81b01d66d8bfb591277f8f96Nadav Rotem/// op 428c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// (Ops[1].first op Ops[1].first op ... Ops[1].first) <- Ops[1].second times 429c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// op 430c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// ... 431c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// op 432c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// (Ops[N].first op Ops[N].first op ... Ops[N].first) <- Ops[N].second times 433c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// 4347ecfcc163956a9e27845ac217f6c650658631030Duncan Sands/// Note that the values Ops[0].first, ..., Ops[N].first are all distinct. 435c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// 436c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// This routine may modify the function, in which case it returns 'true'. The 437c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// changes it makes may well be destructive, changing the value computed by 'I' 438c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// to something completely different. Thus if the routine returns 'true' then 439c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// you MUST either replace I with a new expression computed from the Ops array, 440c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// or use RewriteExprTree to put the values back in. 4410fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// 4420fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// A leaf node is either not a binary operation of the same kind as the root 4430fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// node 'I' (i.e. is not a binary operator at all, or is, but with a different 4440fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// opcode), or is the same kind of binary operator but has a use which either 4450fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// does not belong to the expression, or does belong to the expression but is 4460fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// a leaf node. Every leaf node has at least one use that is a non-leaf node 4470fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// of the expression, while for non-leaf nodes (except for the root 'I') every 4480fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// use is a non-leaf node of the expression. 4490fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// 4500fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// For example: 4510fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// expression graph node names 4520fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// 4530fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// + | I 4540fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// / \ | 4550fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// + + | A, B 4560fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// / \ / \ | 4570fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// * + * | C, D, E 4580fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// / \ / \ / \ | 4590fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// + * | F, G 4600fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// 4610fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// The leaf nodes are C, E, F and G. The Ops array will contain (maybe not in 462c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// that order) (C, 1), (E, 1), (F, 2), (G, 2). 4630fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// 4640fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// The expression is maximal: if some instruction is a binary operator of the 4650fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// same kind as 'I', and all of its uses are non-leaf nodes of the expression, 4660fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// then the instruction also belongs to the expression, is not a leaf node of 4670fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// it, and its operands also belong to the expression (but may be leaf nodes). 468c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner/// 4690fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// NOTE: This routine will set operands of non-leaf non-root nodes to undef in 4700fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// order to ensure that every non-root node in the expression has *exactly one* 4710fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// use by a non-leaf node of the expression. This destruction means that the 472eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands/// caller MUST either replace 'I' with a new expression or use something like 473c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// RewriteExprTree to put the values back in if the routine indicates that it 474c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands/// made a change by returning 'true'. 475e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// 4760fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// In the above example either the right operand of A or the left operand of B 4770fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// will be replaced by undef. If it is B's operand then this gives: 4780fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// 4790fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// + | I 4800fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// / \ | 4810fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// + + | A, B - operand of B replaced with undef 4820fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// / \ \ | 4830fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// * + * | C, D, E 4840fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// / \ / \ / \ | 4850fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// + * | F, G 4860fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// 487eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands/// Note that such undef operands can only be reached by passing through 'I'. 488eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands/// For example, if you visit operands recursively starting from a leaf node 489eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands/// then you will never see such an undef operand unless you get back to 'I', 4900fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// which requires passing through a phi node. 4910fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// 4920fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// Note that this routine may also mutate binary operators of the wrong type 4930fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// that have all uses inside the expression (i.e. only used by non-leaf nodes 4940fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// of the expression) if it can turn them into binary operators of the right 4950fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands/// type and thus make the expression bigger. 4960fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 497c038a7833565ecf92a699371d448135a097c9e2fDuncan Sandsstatic bool LinearizeExprTree(BinaryOperator *I, 498c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands SmallVectorImpl<RepeatedValue> &Ops) { 4990fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "LINEARIZE: " << *I << '\n'); 500c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands unsigned Bitwidth = I->getType()->getScalarType()->getPrimitiveSizeInBits(); 501c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands unsigned Opcode = I->getOpcode(); 502c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands assert(Instruction::isAssociative(Opcode) && 503c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Instruction::isCommutative(Opcode) && 504c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands "Expected an associative and commutative operation!"); 5050fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 5060fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Visit all operands of the expression, keeping track of their weight (the 5070fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // number of paths from the expression root to the operand, or if you like 5080fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // the number of times that operand occurs in the linearized expression). 5090fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // For example, if I = X + A, where X = A + B, then I, X and B have weight 1 5100fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // while A has weight two. 5110fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 5120fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Worklist of non-leaf nodes (their operands are in the expression too) along 5130fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // with their weights, representing a certain number of paths to the operator. 5140fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // If an operator occurs in the worklist multiple times then we found multiple 5150fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // ways to get to it. 516c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands SmallVector<std::pair<BinaryOperator*, APInt>, 8> Worklist; // (Op, Weight) 517c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Worklist.push_back(std::make_pair(I, APInt(Bitwidth, 1))); 518c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands bool MadeChange = false; 519c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 5200fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Leaves of the expression are values that either aren't the right kind of 5210fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // operation (eg: a constant, or a multiply in an add tree), or are, but have 5220fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // some uses that are not inside the expression. For example, in I = X + X, 5230fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // X = A + B, the value X has two uses (by I) that are in the expression. If 5240fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // X has any other uses, for example in a return instruction, then we consider 5250fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // X to be a leaf, and won't analyze it further. When we first visit a value, 5260fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // if it has more than one use then at first we conservatively consider it to 5270fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // be a leaf. Later, as the expression is explored, we may discover some more 5280fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // uses of the value from inside the expression. If all uses turn out to be 5290fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // from within the expression (and the value is a binary operator of the right 5300fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // kind) then the value is no longer considered to be a leaf, and its operands 5310fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // are explored. 5320fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 5330fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Leaves - Keeps track of the set of putative leaves as well as the number of 5340fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // paths to each leaf seen so far. 5355f9e4c1189ab4a8ea1b0000d9337060ac3cac26eDuncan Sands typedef DenseMap<Value*, APInt> LeafMap; 5360fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands LeafMap Leaves; // Leaf -> Total weight so far. 5370fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands SmallVector<Value*, 8> LeafOrder; // Ensure deterministic leaf output order. 538f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner 5390fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands#ifndef NDEBUG 5400fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands SmallPtrSet<Value*, 8> Visited; // For sanity checking the iteration scheme. 5410fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands#endif 5420fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands while (!Worklist.empty()) { 543c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands std::pair<BinaryOperator*, APInt> P = Worklist.pop_back_val(); 5440fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands I = P.first; // We examine the operands of this binary operator. 5450fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 5460fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands for (unsigned OpIdx = 0; OpIdx < 2; ++OpIdx) { // Visit operands. 5470fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *Op = I->getOperand(OpIdx); 548c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands APInt Weight = P.second; // Number of paths to this operand. 5490fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "OPERAND: " << *Op << " (" << Weight << ")\n"); 5500fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(!Op->use_empty() && "No uses, so how did we get to it?!"); 5510fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 5520fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // If this is a binary operation of the right kind with only one use then 5530fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // add its operands to the expression. 5540fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (BinaryOperator *BO = isReassociableOp(Op, Opcode)) { 5550fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(Visited.insert(Op) && "Not first visit!"); 5560fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "DIRECT ADD: " << *Op << " (" << Weight << ")\n"); 5570fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Worklist.push_back(std::make_pair(BO, Weight)); 5580fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands continue; 5590fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 560e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 5610fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Appears to be a leaf. Is the operand already in the set of leaves? 5620fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands LeafMap::iterator It = Leaves.find(Op); 5630fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (It == Leaves.end()) { 5640fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Not in the leaf map. Must be the first time we saw this operand. 5650fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(Visited.insert(Op) && "Not first visit!"); 5660fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (!Op->hasOneUse()) { 5670fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // This value has uses not accounted for by the expression, so it is 5680fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // not safe to modify. Mark it as being a leaf. 5690fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "ADD USES LEAF: " << *Op << " (" << Weight << ")\n"); 5700fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands LeafOrder.push_back(Op); 5710fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Leaves[Op] = Weight; 5720fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands continue; 5730fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 5740fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // No uses outside the expression, try morphing it. 5750fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } else if (It != Leaves.end()) { 5760fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Already in the leaf map. 5770fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(Visited.count(Op) && "In leaf map but not visited!"); 5780fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 5790fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Update the number of paths to the leaf. 580c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands IncorporateWeight(It->second, Weight, Opcode); 5810fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 58220b2d21509b3d5a10ec5d7be6dea8afa9e92fdeeDuncan Sands#if 0 // TODO: Re-enable once PR13021 is fixed. 5830fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // The leaf already has one use from inside the expression. As we want 5840fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // exactly one such use, drop this new use of the leaf. 5850fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(!Op->hasOneUse() && "Only one use, but we got here twice!"); 5860fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands I->setOperand(OpIdx, UndefValue::get(I->getType())); 5870fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands MadeChange = true; 588e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 5890fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // If the leaf is a binary operation of the right kind and we now see 5900fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // that its multiple original uses were in fact all by nodes belonging 5910fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // to the expression, then no longer consider it to be a leaf and add 5920fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // its operands to the expression. 5930fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (BinaryOperator *BO = isReassociableOp(Op, Opcode)) { 5940fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "UNLEAF: " << *Op << " (" << It->second << ")\n"); 5950fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Worklist.push_back(std::make_pair(BO, It->second)); 5960fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Leaves.erase(It); 5970fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands continue; 5980fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 59920b2d21509b3d5a10ec5d7be6dea8afa9e92fdeeDuncan Sands#endif 600fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 6010fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // If we still have uses that are not accounted for by the expression 6020fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // then it is not safe to modify the value. 6030fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (!Op->hasOneUse()) 6040fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands continue; 6054fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 6060fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // No uses outside the expression, try morphing it. 6070fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Weight = It->second; 6080fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Leaves.erase(It); // Since the value may be morphed below. 6090fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 610c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 6110fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // At this point we have a value which, first of all, is not a binary 6120fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // expression of the right kind, and secondly, is only used inside the 6130fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // expression. This means that it can safely be modified. See if we 6140fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // can usefully morph it into an expression of the right kind. 6150fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert((!isa<Instruction>(Op) || 6160fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands cast<Instruction>(Op)->getOpcode() != Opcode) && 6170fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands "Should have been handled above!"); 6180fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(Op->hasOneUse() && "Has uses outside the expression tree!"); 6190fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 6200fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // If this is a multiply expression, turn any internal negations into 6210fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // multiplies by -1 so they can be reassociated. 6220fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands BinaryOperator *BO = dyn_cast<BinaryOperator>(Op); 6230fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (Opcode == Instruction::Mul && BO && BinaryOperator::isNeg(BO)) { 6240fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "MORPH LEAF: " << *Op << " (" << Weight << ") TO "); 625841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands BO = LowerNegateToMultiply(BO); 6260fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << *BO << 'n'); 6270fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Worklist.push_back(std::make_pair(BO, Weight)); 6280fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands MadeChange = true; 6290fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands continue; 6300fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 631c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 6320fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Failed to morph into an expression of the right type. This really is 6330fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // a leaf. 6340fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "ADD LEAF: " << *Op << " (" << Weight << ")\n"); 6350fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(!isReassociableOp(Op, Opcode) && "Value was morphed?"); 6360fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands LeafOrder.push_back(Op); 6370fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Leaves[Op] = Weight; 6380fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 6390fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 640e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 6410fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // The leaves, repeated according to their weights, represent the linearized 6420fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // form of the expression. 6430fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands for (unsigned i = 0, e = LeafOrder.size(); i != e; ++i) { 6440fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *V = LeafOrder[i]; 6450fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands LeafMap::iterator It = Leaves.find(V); 6460fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (It == Leaves.end()) 647c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // Node initially thought to be a leaf wasn't. 6480fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands continue; 6490fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(!isReassociableOp(V, Opcode) && "Shouldn't be a leaf!"); 650c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands APInt Weight = It->second; 651c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (Weight.isMinValue()) 652c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // Leaf already output or weight reduction eliminated it. 653c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands continue; 6540fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Ensure the leaf is only output once. 655c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands It->second = 0; 656c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Ops.push_back(std::make_pair(V, Weight)); 657c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } 658c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands 659c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // For nilpotent operations or addition there may be no operands, for example 660c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // because the expression was "X xor X" or consisted of 2^Bitwidth additions: 661c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands // in both cases the weight reduces to 0 causing the value to be skipped. 662c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands if (Ops.empty()) { 6637ecfcc163956a9e27845ac217f6c650658631030Duncan Sands Constant *Identity = ConstantExpr::getBinOpIdentity(Opcode, I->getType()); 664ee5a094ccf1f04d3fcc92ac4d2fc8a2926cbb232Duncan Sands assert(Identity && "Associative operation without identity!"); 665c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Ops.push_back(std::make_pair(Identity, APInt(Bitwidth, 1))); 6660fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 667c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands 668c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands return MadeChange; 669c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner} 670c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 671c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner// RewriteExprTree - Now that the operands for this expression tree are 6720fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands// linearized and optimized, emit them in-order. 673e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattnervoid Reassociate::RewriteExprTree(BinaryOperator *I, 6740fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands SmallVectorImpl<ValueEntry> &Ops) { 6750fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands assert(Ops.size() > 1 && "Single values should be used directly!"); 6760fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 677b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands // Since our optimizations should never increase the number of operations, the 678b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands // new expression can usually be written reusing the existing binary operators 6790fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // from the original expression tree, without creating any new instructions, 6800fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // though the rewritten expression may have a completely different topology. 6810fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // We take care to not change anything if the new expression will be the same 6820fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // as the original. If more than trivial changes (like commuting operands) 6830fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // were made then we are obliged to clear out any optional subclass data like 6840fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // nsw flags. 6850fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 6860fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands /// NodesToRewrite - Nodes from the original expression available for writing 6870fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands /// the new expression into. 6880fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands SmallVector<BinaryOperator*, 8> NodesToRewrite; 6890fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands unsigned Opcode = I->getOpcode(); 6902923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands BinaryOperator *Op = I; 6910fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 692b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// NotRewritable - The operands being written will be the leaves of the new 693b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// expression and must not be used as inner nodes (via NodesToRewrite) by 694b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// mistake. Inner nodes are always reassociable, and usually leaves are not 695b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// (if they were they would have been incorporated into the expression and so 696b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// would not be leaves), so most of the time there is no danger of this. But 697b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// in rare cases a leaf may become reassociable if an optimization kills uses 698b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// of it, or it may momentarily become reassociable during rewriting (below) 699b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// due it being removed as an operand of one of its uses. Ensure that misuse 700b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// of leaf nodes as inner nodes cannot occur by remembering all of the future 701b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands /// leaves and refusing to reuse any of them as inner nodes. 702b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands SmallPtrSet<Value*, 8> NotRewritable; 703b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands for (unsigned i = 0, e = Ops.size(); i != e; ++i) 704b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands NotRewritable.insert(Ops[i].Op); 705b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands 706eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands // ExpressionChanged - Non-null if the rewritten expression differs from the 707eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands // original in some non-trivial way, requiring the clearing of optional flags. 708eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands // Flags are cleared from the operator in ExpressionChanged up to I inclusive. 709eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands BinaryOperator *ExpressionChanged = 0; 7102d5f8ca3d180832d168e59e2bf3d85317e86287dDuncan Sands for (unsigned i = 0; ; ++i) { 7110fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // The last operation (which comes earliest in the IR) is special as both 7120fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // operands will come from Ops, rather than just one with the other being 7130fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // a subexpression. 7140fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (i+2 == Ops.size()) { 7150fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *NewLHS = Ops[i].Op; 7160fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *NewRHS = Ops[i+1].Op; 7170fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *OldLHS = Op->getOperand(0); 7180fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *OldRHS = Op->getOperand(1); 7190fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 7200fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (NewLHS == OldLHS && NewRHS == OldRHS) 7210fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Nothing changed, leave it alone. 7220fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands break; 7230fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 7240fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (NewLHS == OldRHS && NewRHS == OldLHS) { 7250fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // The order of the operands was reversed. Swap them. 7260fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "RA: " << *Op << '\n'); 7270fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Op->swapOperands(); 7280fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "TO: " << *Op << '\n'); 7290fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands MadeChange = true; 7300fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands ++NumChanged; 7310fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands break; 7320fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 7330fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 7340fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // The new operation differs non-trivially from the original. Overwrite 7350fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // the old operands with the new ones. 7360fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "RA: " << *Op << '\n'); 7370fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (NewLHS != OldLHS) { 738b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands BinaryOperator *BO = isReassociableOp(OldLHS, Opcode); 739b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands if (BO && !NotRewritable.count(BO)) 7400fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands NodesToRewrite.push_back(BO); 7410fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Op->setOperand(0, NewLHS); 7420fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 7430fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (NewRHS != OldRHS) { 744b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands BinaryOperator *BO = isReassociableOp(OldRHS, Opcode); 745b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands if (BO && !NotRewritable.count(BO)) 7460fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands NodesToRewrite.push_back(BO); 7470fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Op->setOperand(1, NewRHS); 7480fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 7490fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "TO: " << *Op << '\n'); 7500fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 751eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands ExpressionChanged = Op; 752c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner MadeChange = true; 753c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner ++NumChanged; 754e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 7550fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands break; 756c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } 757c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 7580fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Not the last operation. The left-hand side will be a sub-expression 7590fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // while the right-hand side will be the current element of Ops. 7600fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *NewRHS = Ops[i].Op; 7610fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (NewRHS != Op->getOperand(1)) { 7620fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "RA: " << *Op << '\n'); 7630fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (NewRHS == Op->getOperand(0)) { 7640fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // The new right-hand side was already present as the left operand. If 7650fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // we are lucky then swapping the operands will sort out both of them. 7660fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Op->swapOperands(); 7670fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } else { 7680fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Overwrite with the new right-hand side. 769b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands BinaryOperator *BO = isReassociableOp(Op->getOperand(1), Opcode); 770b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands if (BO && !NotRewritable.count(BO)) 7710fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands NodesToRewrite.push_back(BO); 7720fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Op->setOperand(1, NewRHS); 773eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands ExpressionChanged = Op; 7740fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 7750fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "TO: " << *Op << '\n'); 7760fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands MadeChange = true; 7770fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands ++NumChanged; 7780fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 77946985a14409486293b689ca07dd07d7482734795Dan Gohman 7800fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Now deal with the left-hand side. If this is already an operation node 7810fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // from the original expression then just rewrite the rest of the expression 7820fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // into it. 783b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands BinaryOperator *BO = isReassociableOp(Op->getOperand(0), Opcode); 784b8e1111fbf71766903d2fc7b158dc612df097ea3Duncan Sands if (BO && !NotRewritable.count(BO)) { 7852923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands Op = BO; 7860fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands continue; 7870fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 78846985a14409486293b689ca07dd07d7482734795Dan Gohman 7890fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Otherwise, grab a spare node from the original expression and use that as 79096d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands // the left-hand side. If there are no nodes left then the optimizers made 79196d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands // an expression with more nodes than the original! This usually means that 79296d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands // they did something stupid but it might mean that the problem was just too 79396d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands // hard (finding the mimimal number of multiplications needed to realize a 79496d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands // multiplication expression is NP-complete). Whatever the reason, smart or 79596d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands // stupid, create a new node if there are none left. 7962923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands BinaryOperator *NewOp; 79796d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands if (NodesToRewrite.empty()) { 79896d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands Constant *Undef = UndefValue::get(I->getType()); 7992923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands NewOp = BinaryOperator::Create(Instruction::BinaryOps(Opcode), 8002923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands Undef, Undef, "", I); 8012923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands } else { 8022923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands NewOp = NodesToRewrite.pop_back_val(); 80396d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands } 80496d2eff5c6713a2c5fd2cd61545e49637c332975Duncan Sands 8050fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "RA: " << *Op << '\n'); 8062923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands Op->setOperand(0, NewOp); 8070fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands DEBUG(dbgs() << "TO: " << *Op << '\n'); 808eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands ExpressionChanged = Op; 809c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner MadeChange = true; 810c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner ++NumChanged; 8112923bca2b5fe46189c4c5572047e1d95946ac549Duncan Sands Op = NewOp; 812c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } 813e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 814eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands // If the expression changed non-trivially then clear out all subclass data 8152d5f8ca3d180832d168e59e2bf3d85317e86287dDuncan Sands // starting from the operator specified in ExpressionChanged, and compactify 8162d5f8ca3d180832d168e59e2bf3d85317e86287dDuncan Sands // the operators to just before the expression root to guarantee that the 8172d5f8ca3d180832d168e59e2bf3d85317e86287dDuncan Sands // expression tree is dominated by all of Ops. 8182d5f8ca3d180832d168e59e2bf3d85317e86287dDuncan Sands if (ExpressionChanged) 8190fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands do { 820eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands ExpressionChanged->clearSubclassOptionalData(); 821eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands if (ExpressionChanged == I) 8220fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands break; 8232d5f8ca3d180832d168e59e2bf3d85317e86287dDuncan Sands ExpressionChanged->moveBefore(I); 824eacc31acf515c79338e8c94ce8c7c26dd7b2d32aDuncan Sands ExpressionChanged = cast<BinaryOperator>(*ExpressionChanged->use_begin()); 8250fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } while (1); 826e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 8270fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Throw away any left over nodes from the original expression. 8280fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands for (unsigned i = 0, e = NodesToRewrite.size(); i != e; ++i) 829841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(NodesToRewrite[i]); 8304fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 8314fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 832e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// NegateValue - Insert instructions before the instruction pointed to by BI, 833e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// that computes the negative version of the value specified. The negative 834e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// version of the value is returned, and BI is left pointing at the instruction 835e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// that should be processed next by the reassociation pass. 836e79fddedcae1ee8fe7d8571db58447bc722f75dcNick Lewyckystatic Value *NegateValue(Value *V, Instruction *BI) { 83735239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner if (Constant *C = dyn_cast<Constant>(V)) 83835239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner return ConstantExpr::getNeg(C); 839e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 840a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // We are trying to expose opportunity for reassociation. One of the things 841a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // that we want to do to achieve this is to push a negation as deep into an 842a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // expression chain as possible, to expose the add instructions. In practice, 843a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // this means that we turn this: 844a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // X = -(A+12+C+D) into X = -A + -12 + -C + -D = -12 + -A + -C + -D 845a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // so that later, a: Y = 12+X could get reassociated with the -12 to eliminate 846a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // the constants. We assume that instcombine will clean up the mess later if 8479046193e557d559f45dc50df5e20b1fccc90b2acChris Lattner // we introduce tons of unnecessary negation instructions. 848a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // 8490fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (BinaryOperator *I = isReassociableOp(V, Instruction::Add)) { 8500fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Push the negates through the add. 8510fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands I->setOperand(0, NegateValue(I->getOperand(0), BI)); 8520fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands I->setOperand(1, NegateValue(I->getOperand(1), BI)); 8530fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 8540fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // We must move the add instruction here, because the neg instructions do 8550fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // not dominate the old add instruction in general. By moving it, we are 8560fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // assured that the neg instructions we just inserted dominate the 8570fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // instruction we are about to insert after them. 8580fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // 8590fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands I->moveBefore(BI); 8600fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands I->setName(I->getName()+".neg"); 8610fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands return I; 8620fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands } 863e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 86435239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner // Okay, we need to materialize a negated version of V with an instruction. 86535239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner // Scan the use lists of V to see if we have one already. 86635239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){ 867110b75aa7572d3b59b308da7ec1d759e86788f97Gabor Greif User *U = *UI; 868110b75aa7572d3b59b308da7ec1d759e86788f97Gabor Greif if (!BinaryOperator::isNeg(U)) continue; 86935239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner 87035239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner // We found one! Now we have to make sure that the definition dominates 87135239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner // this use. We do this by moving it to the entry block (if it is a 87235239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner // non-instruction value) or right after the definition. These negates will 87335239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner // be zapped by reassociate later, so we don't need much finesse here. 874110b75aa7572d3b59b308da7ec1d759e86788f97Gabor Greif BinaryOperator *TheNeg = cast<BinaryOperator>(U); 8751c91fae649734abe6f8271862fe3ba917e191279Chris Lattner 8761c91fae649734abe6f8271862fe3ba917e191279Chris Lattner // Verify that the negate is in this function, V might be a constant expr. 8771c91fae649734abe6f8271862fe3ba917e191279Chris Lattner if (TheNeg->getParent()->getParent() != BI->getParent()->getParent()) 8781c91fae649734abe6f8271862fe3ba917e191279Chris Lattner continue; 879e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 88035239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner BasicBlock::iterator InsertPt; 88135239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner if (Instruction *InstInput = dyn_cast<Instruction>(V)) { 88235239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner if (InvokeInst *II = dyn_cast<InvokeInst>(InstInput)) { 88335239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner InsertPt = II->getNormalDest()->begin(); 88435239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner } else { 88535239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner InsertPt = InstInput; 88635239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner ++InsertPt; 88735239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner } 88835239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner while (isa<PHINode>(InsertPt)) ++InsertPt; 88935239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner } else { 89035239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner InsertPt = TheNeg->getParent()->getParent()->getEntryBlock().begin(); 89135239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner } 89235239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner TheNeg->moveBefore(InsertPt); 89335239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner return TheNeg; 89435239934517c6fcd52e3e965f40e03f74aa4d11dChris Lattner } 895a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner 896a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // Insert a 'neg' instruction that subtracts the value from zero to get the 897a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // negation. 8984ae5126d041768ab9665cf2f11c024becd76c41fDan Gohman return BinaryOperator::CreateNeg(V, V->getName() + ".neg", BI); 899a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner} 900a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner 9019bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner/// ShouldBreakUpSubtract - Return true if we should break up this subtract of 9029bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner/// X-Y into (X + -Y). 903e79fddedcae1ee8fe7d8571db58447bc722f75dcNick Lewyckystatic bool ShouldBreakUpSubtract(Instruction *Sub) { 9049bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner // If this is a negation, we can't split it up! 905fa82b6eba4e1584d7dba291c28fe908272e1e002Owen Anderson if (BinaryOperator::isNeg(Sub)) 9069bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return false; 907e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 9089bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner // Don't bother to break this up unless either the LHS is an associable add or 9090b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner // subtract or if this is only used by one. 9100b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner if (isReassociableOp(Sub->getOperand(0), Instruction::Add) || 9110b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner isReassociableOp(Sub->getOperand(0), Instruction::Sub)) 9129bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return true; 9130b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner if (isReassociableOp(Sub->getOperand(1), Instruction::Add) || 9145329bb22e9b6374d62919981c1ef8775b42945ebChris Lattner isReassociableOp(Sub->getOperand(1), Instruction::Sub)) 9159bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return true; 916e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling if (Sub->hasOneUse() && 9170b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner (isReassociableOp(Sub->use_back(), Instruction::Add) || 9180b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner isReassociableOp(Sub->use_back(), Instruction::Sub))) 9199bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return true; 920e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 9219bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return false; 9229bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner} 9239bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner 92408b43921e18f314c4fd38049291d323830934c36Chris Lattner/// BreakUpSubtract - If we have (X-Y), and if either X is an add, or if this is 92508b43921e18f314c4fd38049291d323830934c36Chris Lattner/// only used by an add, transform this into (X+(0-Y)) to promote better 92608b43921e18f314c4fd38049291d323830934c36Chris Lattner/// reassociation. 927841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sandsstatic BinaryOperator *BreakUpSubtract(Instruction *Sub) { 9289046193e557d559f45dc50df5e20b1fccc90b2acChris Lattner // Convert a subtract into an add and a neg instruction. This allows sub 9299046193e557d559f45dc50df5e20b1fccc90b2acChris Lattner // instructions to be commuted with other add instructions. 93008b43921e18f314c4fd38049291d323830934c36Chris Lattner // 9319046193e557d559f45dc50df5e20b1fccc90b2acChris Lattner // Calculate the negative value of Operand 1 of the sub instruction, 9329046193e557d559f45dc50df5e20b1fccc90b2acChris Lattner // and set it as the RHS of the add instruction we just made. 93308b43921e18f314c4fd38049291d323830934c36Chris Lattner // 934e79fddedcae1ee8fe7d8571db58447bc722f75dcNick Lewycky Value *NegVal = NegateValue(Sub->getOperand(1), Sub); 935841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands BinaryOperator *New = 9367cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif BinaryOperator::CreateAdd(Sub->getOperand(0), NegVal, "", Sub); 937841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Sub->setOperand(0, Constant::getNullValue(Sub->getType())); // Drop use of op. 938841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Sub->setOperand(1, Constant::getNullValue(Sub->getType())); // Drop use of op. 9396934a04a8c15e9971cd1ea4d5c8df2d7afdd5be5Chris Lattner New->takeName(Sub); 94008b43921e18f314c4fd38049291d323830934c36Chris Lattner 94108b43921e18f314c4fd38049291d323830934c36Chris Lattner // Everyone now refers to the add instruction. 94208b43921e18f314c4fd38049291d323830934c36Chris Lattner Sub->replaceAllUsesWith(New); 9435367b23f76e75ebb680956575346fa8c3d56780fDevang Patel New->setDebugLoc(Sub->getDebugLoc()); 94400b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 945a1fa76cb5443e7b0fe7d36ee1118f80050e746f9David Greene DEBUG(dbgs() << "Negated: " << *New << '\n'); 94608b43921e18f314c4fd38049291d323830934c36Chris Lattner return New; 94708b43921e18f314c4fd38049291d323830934c36Chris Lattner} 94808b43921e18f314c4fd38049291d323830934c36Chris Lattner 9490975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner/// ConvertShiftToMul - If this is a shift of a reassociable multiply or is used 9500975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner/// by one, change this into a multiply by a constant to assist with further 9510975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner/// reassociation. 952841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sandsstatic BinaryOperator *ConvertShiftToMul(Instruction *Shl) { 953841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Constant *MulCst = ConstantInt::get(Shl->getType(), 1); 954841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands MulCst = ConstantExpr::getShl(MulCst, cast<Constant>(Shl->getOperand(1))); 955841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands 956841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands BinaryOperator *Mul = 957841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands BinaryOperator::CreateMul(Shl->getOperand(0), MulCst, "", Shl); 958841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Shl->setOperand(0, UndefValue::get(Shl->getType())); // Drop use of op. 959841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Mul->takeName(Shl); 960841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Shl->replaceAllUsesWith(Mul); 961841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Mul->setDebugLoc(Shl->getDebugLoc()); 962841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands return Mul; 9630975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner} 9640975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner 965e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// FindInOperandList - Scan backwards and forwards among values with the same 966e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// rank as element i to see if X exists. If X does not exist, return i. This 967e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// is useful when scanning for 'x' when we see '-x' because they both get the 968e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// same rank. 9699f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattnerstatic unsigned FindInOperandList(SmallVectorImpl<ValueEntry> &Ops, unsigned i, 970109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner Value *X) { 971109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner unsigned XRank = Ops[i].Rank; 972109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner unsigned e = Ops.size(); 973109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner for (unsigned j = i+1; j != e && Ops[j].Rank == XRank; ++j) 974109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (Ops[j].Op == X) 975109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner return j; 9769506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner // Scan backwards. 977109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner for (unsigned j = i-1; j != ~0U && Ops[j].Rank == XRank; --j) 978109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (Ops[j].Op == X) 979109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner return j; 980109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner return i; 981109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner} 982109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner 983e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// EmitAddTreeOfValues - Emit a tree of add instructions, summing Ops together 984e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// and returning the result. Insert the tree before I. 98555e7098bbc363473c01229517097d2a04e04e9b0Bill Wendlingstatic Value *EmitAddTreeOfValues(Instruction *I, 98655e7098bbc363473c01229517097d2a04e04e9b0Bill Wendling SmallVectorImpl<WeakVH> &Ops){ 987e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (Ops.size() == 1) return Ops.back(); 988e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 989e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *V1 = Ops.back(); 990e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Ops.pop_back(); 991e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *V2 = EmitAddTreeOfValues(I, Ops); 9927cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif return BinaryOperator::CreateAdd(V2, V1, "tmp", I); 993e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 994e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 995e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling/// RemoveFactorFromExpression - If V is an expression tree that is a 996e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// multiplication sequence, and if this sequence contains a multiply by Factor, 997e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// remove Factor from the tree and return the new tree. 998e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris LattnerValue *Reassociate::RemoveFactorFromExpression(Value *V, Value *Factor) { 999e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner BinaryOperator *BO = isReassociableOp(V, Instruction::Mul); 1000e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (!BO) return 0; 1001e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1002c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands SmallVector<RepeatedValue, 8> Tree; 1003c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands MadeChange |= LinearizeExprTree(BO, Tree); 10049f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner SmallVector<ValueEntry, 8> Factors; 1005c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Factors.reserve(Tree.size()); 1006c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands for (unsigned i = 0, e = Tree.size(); i != e; ++i) { 1007c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands RepeatedValue E = Tree[i]; 1008c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Factors.append(E.second.getZExtValue(), 1009c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands ValueEntry(getRank(E.first), E.first)); 1010c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } 1011e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 1012e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner bool FoundFactor = false; 10139506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner bool NeedsNegate = false; 10149506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner for (unsigned i = 0, e = Factors.size(); i != e; ++i) { 1015e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (Factors[i].Op == Factor) { 1016e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner FoundFactor = true; 1017e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Factors.erase(Factors.begin()+i); 1018e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner break; 1019e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 1020e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 10219506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner // If this is a negative version of this factor, remove it. 10229506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner if (ConstantInt *FC1 = dyn_cast<ConstantInt>(Factor)) 10239506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner if (ConstantInt *FC2 = dyn_cast<ConstantInt>(Factors[i].Op)) 10249506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner if (FC1->getValue() == -FC2->getValue()) { 10259506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner FoundFactor = NeedsNegate = true; 10269506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner Factors.erase(Factors.begin()+i); 10279506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner break; 10289506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner } 10299506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner } 1030e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1031e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner if (!FoundFactor) { 1032e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // Make sure to restore the operands to the expression tree. 1033e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner RewriteExprTree(BO, Factors); 1034e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner return 0; 1035e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner } 1036e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 10379506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner BasicBlock::iterator InsertPt = BO; ++InsertPt; 1038e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 10391e7558b65689999089f53ce40ff07564cf498c68Chris Lattner // If this was just a single multiply, remove the multiply and return the only 10401e7558b65689999089f53ce40ff07564cf498c68Chris Lattner // remaining operand. 10411e7558b65689999089f53ce40ff07564cf498c68Chris Lattner if (Factors.size() == 1) { 1042841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(BO); 10439506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner V = Factors[0].Op; 10449506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner } else { 10459506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner RewriteExprTree(BO, Factors); 10469506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner V = BO; 10471e7558b65689999089f53ce40ff07564cf498c68Chris Lattner } 1048e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 10499506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner if (NeedsNegate) 10509506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner V = BinaryOperator::CreateNeg(V, "neg", InsertPt); 1051e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 10529506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner return V; 1053e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 1054e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 1055e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// FindSingleUseMultiplyFactors - If V is a single-use multiply, recursively 1056e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// add its operands as factors, otherwise add V to the list of factors. 1057893075f46e9d07e3fe94e2b0e0f3ff8ae4061549Chris Lattner/// 1058893075f46e9d07e3fe94e2b0e0f3ff8ae4061549Chris Lattner/// Ops is the top-level list of add operands we're trying to factor. 1059e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattnerstatic void FindSingleUseMultiplyFactors(Value *V, 1060893075f46e9d07e3fe94e2b0e0f3ff8ae4061549Chris Lattner SmallVectorImpl<Value*> &Factors, 10610fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands const SmallVectorImpl<ValueEntry> &Ops) { 10620fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands BinaryOperator *BO = isReassociableOp(V, Instruction::Mul); 10630fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (!BO) { 1064e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner Factors.push_back(V); 1065e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner return; 1066e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner } 1067e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1068e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // Otherwise, add the LHS and RHS to the list of factors. 10690fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands FindSingleUseMultiplyFactors(BO->getOperand(1), Factors, Ops); 10700fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands FindSingleUseMultiplyFactors(BO->getOperand(0), Factors, Ops); 1071e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner} 1072e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner 1073f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner/// OptimizeAndOrXor - Optimize a series of operands to an 'and', 'or', or 'xor' 1074f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner/// instruction. This optimizes based on identities. If it can be reduced to 1075f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner/// a single Value, it is returned, otherwise the Ops list is mutated as 1076f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner/// necessary. 10779f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattnerstatic Value *OptimizeAndOrXor(unsigned Opcode, 10789f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner SmallVectorImpl<ValueEntry> &Ops) { 1079f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner // Scan the operand lists looking for X and ~X pairs, along with X,X pairs. 1080f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner // If we find any, we can simplify the expression. X&~X == 0, X|~X == -1. 1081f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 1082f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner // First, check for X and ~X in the operand list. 1083f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner assert(i < Ops.size()); 1084f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner if (BinaryOperator::isNot(Ops[i].Op)) { // Cannot occur for ^. 1085f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner Value *X = BinaryOperator::getNotArgument(Ops[i].Op); 1086f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner unsigned FoundX = FindInOperandList(Ops, i, X); 1087f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner if (FoundX != i) { 10889fdaefad580194353f34b6d72669591f8f9d811aChris Lattner if (Opcode == Instruction::And) // ...&X&~X = 0 1089f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner return Constant::getNullValue(X->getType()); 1090e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 10919fdaefad580194353f34b6d72669591f8f9d811aChris Lattner if (Opcode == Instruction::Or) // ...|X|~X = -1 1092f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner return Constant::getAllOnesValue(X->getType()); 1093f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner } 1094f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner } 1095e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1096f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner // Next, check for duplicate pairs of values, which we assume are next to 1097f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner // each other, due to our sorting criteria. 1098f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner assert(i < Ops.size()); 1099f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner if (i+1 != Ops.size() && Ops[i+1].Op == Ops[i].Op) { 1100f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner if (Opcode == Instruction::And || Opcode == Instruction::Or) { 1101f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner // Drop duplicate values for And and Or. 1102f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner Ops.erase(Ops.begin()+i); 1103f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner --i; --e; 1104f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner ++NumAnnihil; 1105f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner continue; 1106f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner } 1107e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1108f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner // Drop pairs of values for Xor. 1109f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner assert(Opcode == Instruction::Xor); 1110f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner if (e == 2) 1111f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner return Constant::getNullValue(Ops[0].Op->getType()); 1112e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 11139046193e557d559f45dc50df5e20b1fccc90b2acChris Lattner // Y ^ X^X -> Y 1114f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner Ops.erase(Ops.begin()+i, Ops.begin()+i+2); 1115f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner i -= 1; e -= 2; 1116f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner ++NumAnnihil; 1117f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner } 1118f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner } 1119f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner return 0; 1120f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner} 1121e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner 11222d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang/// Helper funciton of CombineXorOpnd(). It creates a bitwise-and 11232d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang/// instruction with the given two operands, and return the resulting 11242d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang/// instruction. There are two special cases: 1) if the constant operand is 0, 11252d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang/// it will return NULL. 2) if the constant is ~0, the symbolic operand will 11262d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang/// be returned. 11272d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yangstatic Value *createAndInstr(Instruction *InsertBefore, Value *Opnd, 11282d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang const APInt &ConstOpnd) { 11292d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (ConstOpnd != 0) { 11302d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (!ConstOpnd.isAllOnesValue()) { 11312d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang LLVMContext &Ctx = Opnd->getType()->getContext(); 11322d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Instruction *I; 11332d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang I = BinaryOperator::CreateAnd(Opnd, ConstantInt::get(Ctx, ConstOpnd), 11342d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang "and.ra", InsertBefore); 11352d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang I->setDebugLoc(InsertBefore->getDebugLoc()); 11362d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return I; 11372d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 11382d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return Opnd; 11392d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 11402d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return 0; 11412d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang} 11422d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 11432d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// Helper function of OptimizeXor(). It tries to simplify "Opnd1 ^ ConstOpnd" 11442d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// into "R ^ C", where C would be 0, and R is a symbolic value. 11452d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// 11462d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// If it was successful, true is returned, and the "R" and "C" is returned 11472d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// via "Res" and "ConstOpnd", respectively; otherwise, false is returned, 11482d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// and both "Res" and "ConstOpnd" remain unchanged. 11492d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// 11502d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yangbool Reassociate::CombineXorOpnd(Instruction *I, XorOpnd *Opnd1, 11512d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang APInt &ConstOpnd, Value *&Res) { 11522d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Xor-Rule 1: (x | c1) ^ c2 = (x | c1) ^ (c1 ^ c1) ^ c2 11532d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // = ((x | c1) ^ c1) ^ (c1 ^ c2) 11542d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // = (x & ~c1) ^ (c1 ^ c2) 11552d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // It is useful only when c1 == c2. 11562d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Opnd1->isOrExpr() && Opnd1->getConstPart() != 0) { 11572d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (!Opnd1->getValue()->hasOneUse()) 11582d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return false; 11592d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 11602d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang const APInt &C1 = Opnd1->getConstPart(); 11612d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (C1 != ConstOpnd) 11622d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return false; 11632d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 11642d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *X = Opnd1->getSymbolicPart(); 11652d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Res = createAndInstr(I, X, ~C1); 11662d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // ConstOpnd was C2, now C1 ^ C2. 11672d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang ConstOpnd ^= C1; 11682d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 11692d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Instruction *T = dyn_cast<Instruction>(Opnd1->getValue())) 11702d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang RedoInsts.insert(T); 11712d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return true; 11722d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 11732d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return false; 11742d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang} 11752d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 11762d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 11772d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// Helper function of OptimizeXor(). It tries to simplify 11782d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// "Opnd1 ^ Opnd2 ^ ConstOpnd" into "R ^ C", where C would be 0, and R is a 11792d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// symbolic value. 11802d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// 11812d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// If it was successful, true is returned, and the "R" and "C" is returned 11822d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// via "Res" and "ConstOpnd", respectively (If the entire expression is 11832d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// evaluated to a constant, the Res is set to NULL); otherwise, false is 11842d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang// returned, and both "Res" and "ConstOpnd" remain unchanged. 11852d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yangbool Reassociate::CombineXorOpnd(Instruction *I, XorOpnd *Opnd1, XorOpnd *Opnd2, 11862d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang APInt &ConstOpnd, Value *&Res) { 11872d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *X = Opnd1->getSymbolicPart(); 11882d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (X != Opnd2->getSymbolicPart()) 11892d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return false; 11902d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 11912d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // This many instruction become dead.(At least "Opnd1 ^ Opnd2" will die.) 11922d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang int DeadInstNum = 1; 11932d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Opnd1->getValue()->hasOneUse()) 11942d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang DeadInstNum++; 11952d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Opnd2->getValue()->hasOneUse()) 11962d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang DeadInstNum++; 11972d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 11982d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Xor-Rule 2: 11992d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // (x | c1) ^ (x & c2) 12002d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // = (x|c1) ^ (x&c2) ^ (c1 ^ c1) = ((x|c1) ^ c1) ^ (x & c2) ^ c1 12012d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // = (x & ~c1) ^ (x & c2) ^ c1 // Xor-Rule 1 12022d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // = (x & c3) ^ c1, where c3 = ~c1 ^ c2 // Xor-rule 3 12032d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // 12042d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Opnd1->isOrExpr() != Opnd2->isOrExpr()) { 12052d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Opnd2->isOrExpr()) 12062d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang std::swap(Opnd1, Opnd2); 12072d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12084d4c54d29ff911f59fe2be1a31331dbcbb741f5fShuxin Yang const APInt &C1 = Opnd1->getConstPart(); 12094d4c54d29ff911f59fe2be1a31331dbcbb741f5fShuxin Yang const APInt &C2 = Opnd2->getConstPart(); 12102d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang APInt C3((~C1) ^ C2); 12112d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12122d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Do not increase code size! 12132d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (C3 != 0 && !C3.isAllOnesValue()) { 12142d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang int NewInstNum = ConstOpnd != 0 ? 1 : 2; 12152d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (NewInstNum > DeadInstNum) 12162d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return false; 12172d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 12182d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12192d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Res = createAndInstr(I, X, C3); 12202d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang ConstOpnd ^= C1; 12212d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12222d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } else if (Opnd1->isOrExpr()) { 12232d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Xor-Rule 3: (x | c1) ^ (x | c2) = (x & c3) ^ c3 where c3 = c1 ^ c2 12242d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // 12254d4c54d29ff911f59fe2be1a31331dbcbb741f5fShuxin Yang const APInt &C1 = Opnd1->getConstPart(); 12264d4c54d29ff911f59fe2be1a31331dbcbb741f5fShuxin Yang const APInt &C2 = Opnd2->getConstPart(); 12272d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang APInt C3 = C1 ^ C2; 12282d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12292d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Do not increase code size 12302d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (C3 != 0 && !C3.isAllOnesValue()) { 12312d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang int NewInstNum = ConstOpnd != 0 ? 1 : 2; 12322d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (NewInstNum > DeadInstNum) 12332d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return false; 12342d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 12352d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12362d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Res = createAndInstr(I, X, C3); 12372d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang ConstOpnd ^= C3; 12382d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } else { 12392d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Xor-Rule 4: (x & c1) ^ (x & c2) = (x & (c1^c2)) 12402d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // 12414d4c54d29ff911f59fe2be1a31331dbcbb741f5fShuxin Yang const APInt &C1 = Opnd1->getConstPart(); 12424d4c54d29ff911f59fe2be1a31331dbcbb741f5fShuxin Yang const APInt &C2 = Opnd2->getConstPart(); 12432d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang APInt C3 = C1 ^ C2; 12442d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Res = createAndInstr(I, X, C3); 12452d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 12462d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12472d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Put the original operands in the Redo list; hope they will be deleted 12482d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // as dead code. 12492d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Instruction *T = dyn_cast<Instruction>(Opnd1->getValue())) 12502d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang RedoInsts.insert(T); 12512d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Instruction *T = dyn_cast<Instruction>(Opnd2->getValue())) 12522d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang RedoInsts.insert(T); 12532d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12542d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return true; 12552d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang} 12562d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12572d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang/// Optimize a series of operands to an 'xor' instruction. If it can be reduced 12582d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang/// to a single Value, it is returned, otherwise the Ops list is mutated as 12592d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang/// necessary. 12602d1001064989b7fa79507816fc17d467fc00a2f2Shuxin YangValue *Reassociate::OptimizeXor(Instruction *I, 12612d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang SmallVectorImpl<ValueEntry> &Ops) { 12622d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Value *V = OptimizeAndOrXor(Instruction::Xor, Ops)) 12632d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return V; 12642d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12652d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Ops.size() == 1) 12662d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return 0; 12672d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12682d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang SmallVector<XorOpnd, 8> Opnds; 12694fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang SmallVector<XorOpnd*, 8> OpndPtrs; 12702d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Type *Ty = Ops[0].Op->getType(); 12712d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang APInt ConstOpnd(Ty->getIntegerBitWidth(), 0); 12722d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12732d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Step 1: Convert ValueEntry to XorOpnd 12742d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 12752d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *V = Ops[i].Op; 12762d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (!isa<ConstantInt>(V)) { 12772d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang XorOpnd O(V); 12782d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang O.setSymbolicRank(getRank(O.getSymbolicPart())); 12792d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Opnds.push_back(O); 12802d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } else 12812d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang ConstOpnd ^= cast<ConstantInt>(V)->getValue(); 12822d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 12832d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12844fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang // NOTE: From this point on, do *NOT* add/delete element to/from "Opnds". 12854fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang // It would otherwise invalidate the "Opnds"'s iterator, and hence invalidate 12864fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang // the "OpndPtrs" as well. For the similar reason, do not fuse this loop 12874fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang // with the previous loop --- the iterator of the "Opnds" may be invalidated 12884fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang // when new elements are added to the vector. 12894fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang for (unsigned i = 0, e = Opnds.size(); i != e; ++i) 12904fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang OpndPtrs.push_back(&Opnds[i]); 12914fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang 12922d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Step 2: Sort the Xor-Operands in a way such that the operands containing 12932d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // the same symbolic value cluster together. For instance, the input operand 12942d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // sequence ("x | 123", "y & 456", "x & 789") will be sorted into: 12952d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // ("x | 123", "x & 789", "y & 456"). 12964fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang std::sort(OpndPtrs.begin(), OpndPtrs.end(), XorOpnd::PtrSortFunctor()); 12972d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 12982d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Step 3: Combine adjacent operands 12992d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang XorOpnd *PrevOpnd = 0; 13002d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang bool Changed = false; 13012d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang for (unsigned i = 0, e = Opnds.size(); i < e; i++) { 13024fd00c55d0e31770505e6517afdfadfa3482d889Shuxin Yang XorOpnd *CurrOpnd = OpndPtrs[i]; 13032d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // The combined value 13042d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *CV; 13052d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 13062d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Step 3.1: Try simplifying "CurrOpnd ^ ConstOpnd" 13072d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (ConstOpnd != 0 && CombineXorOpnd(I, CurrOpnd, ConstOpnd, CV)) { 13082d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Changed = true; 13092d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (CV) 13102d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang *CurrOpnd = XorOpnd(CV); 13112d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang else { 13122d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang CurrOpnd->Invalidate(); 13132d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang continue; 13142d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13152d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13162d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 13172d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (!PrevOpnd || CurrOpnd->getSymbolicPart() != PrevOpnd->getSymbolicPart()) { 13182d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang PrevOpnd = CurrOpnd; 13192d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang continue; 13202d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13212d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 13222d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // step 3.2: When previous and current operands share the same symbolic 13232d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // value, try to simplify "PrevOpnd ^ CurrOpnd ^ ConstOpnd" 13242d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // 13252d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (CombineXorOpnd(I, CurrOpnd, PrevOpnd, ConstOpnd, CV)) { 13262d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Remove previous operand 13272d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang PrevOpnd->Invalidate(); 13282d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (CV) { 13292d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang *CurrOpnd = XorOpnd(CV); 13302d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang PrevOpnd = CurrOpnd; 13312d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } else { 13322d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang CurrOpnd->Invalidate(); 13332d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang PrevOpnd = 0; 13342d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13352d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Changed = true; 13362d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13372d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13382d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 13392d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang // Step 4: Reassemble the Ops 13402d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Changed) { 13412d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Ops.clear(); 13422d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang for (unsigned int i = 0, e = Opnds.size(); i < e; i++) { 13432d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang XorOpnd &O = Opnds[i]; 13442d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (O.isInvalid()) 13452d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang continue; 13462d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang ValueEntry VE(getRank(O.getValue()), O.getValue()); 13472d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Ops.push_back(VE); 13482d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13492d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (ConstOpnd != 0) { 13502d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Value *C = ConstantInt::get(Ty->getContext(), ConstOpnd); 13512d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang ValueEntry VE(getRank(C), C); 13522d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang Ops.push_back(VE); 13532d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13542d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang int Sz = Ops.size(); 13552d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Sz == 1) 13562d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return Ops.back().Op; 13572d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang else if (Sz == 0) { 13582d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang assert(ConstOpnd == 0); 13592d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return ConstantInt::get(Ty->getContext(), ConstOpnd); 13602d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13612d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang } 13622d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 13632d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return 0; 13642d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang} 13652d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 1366f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner/// OptimizeAdd - Optimize a series of operands to an 'add' instruction. This 1367f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner/// optimizes based on identities. If it can be reduced to a single Value, it 1368f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner/// is returned, otherwise the Ops list is mutated as necessary. 13699f7b7089be854c323f8d9a4627d80e47adf496e6Chris LattnerValue *Reassociate::OptimizeAdd(Instruction *I, 13709f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner SmallVectorImpl<ValueEntry> &Ops) { 1371f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner // Scan the operand lists looking for X and -X pairs. If we find any, we 137269e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // can simplify the expression. X+-X == 0. While we're at it, scan for any 137369e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // duplicates. We want to canonicalize Y+Y+Y+Z -> 3*Y+Z. 13749506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner // 13759506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner // TODO: We could handle "X + ~X" -> "-1" if we wanted, since "-X = ~X+1". 13769506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner // 1377f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 137869e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner Value *TheOp = Ops[i].Op; 137969e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // Check to see if we've seen this operand before. If so, we factor all 1380f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner // instances of the operand together. Due to our sorting criteria, we know 1381f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner // that these need to be next to each other in the vector. 1382f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner if (i+1 != Ops.size() && Ops[i+1].Op == TheOp) { 1383f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner // Rescan the list, remove all instances of this operand from the expr. 138469e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner unsigned NumFound = 0; 1385f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner do { 1386f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner Ops.erase(Ops.begin()+i); 138769e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner ++NumFound; 1388f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner } while (i != Ops.size() && Ops[i].Op == TheOp); 1389e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1390f8a447de162a2896a8a044931fb63de713dbc6b9Chris Lattner DEBUG(errs() << "\nFACTORING [" << NumFound << "]: " << *TheOp << '\n'); 139169e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner ++NumFactor; 1392e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 139369e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // Insert a new multiply. 139469e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner Value *Mul = ConstantInt::get(cast<IntegerType>(I->getType()), NumFound); 139569e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner Mul = BinaryOperator::CreateMul(TheOp, Mul, "factor", I); 1396e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 139769e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // Now that we have inserted a multiply, optimize it. This allows us to 139869e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // handle cases that require multiple factoring steps, such as this: 139969e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // (X*2) + (X*2) + (X*2) -> (X*2)*3 -> X*6 1400841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(cast<Instruction>(Mul)); 1401e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 140269e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // If every add operand was a duplicate, return the multiply. 140369e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner if (Ops.empty()) 140469e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner return Mul; 1405e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 140669e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // Otherwise, we had some input that didn't have the dupe, such as 140769e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // "A + A + B" -> "A*2 + B". Add the new multiply to the list of 140869e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // things being added by this operation. 140969e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner Ops.insert(Ops.begin(), ValueEntry(getRank(Mul), Mul)); 1410e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1411f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner --i; 1412f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner e = Ops.size(); 1413f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner continue; 141469e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner } 1415e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1416f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner // Check for X and -X in the operand list. 141769e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner if (!BinaryOperator::isNeg(TheOp)) 1418f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner continue; 1419e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 142069e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner Value *X = BinaryOperator::getNegArgument(TheOp); 1421f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner unsigned FoundX = FindInOperandList(Ops, i, X); 1422f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner if (FoundX == i) 1423f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner continue; 1424e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1425f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner // Remove X and -X from the operand list. 14269fdaefad580194353f34b6d72669591f8f9d811aChris Lattner if (Ops.size() == 2) 1427f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner return Constant::getNullValue(X->getType()); 1428e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1429f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner Ops.erase(Ops.begin()+i); 1430f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner if (i < FoundX) 1431f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner --FoundX; 1432f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner else 1433f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner --i; // Need to back up an extra one. 1434f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner Ops.erase(Ops.begin()+FoundX); 1435f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner ++NumAnnihil; 1436f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner --i; // Revisit element. 1437f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner e -= 2; // Removed two elements. 1438f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner } 1439e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 144094285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // Scan the operand list, checking to see if there are any common factors 144194285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // between operands. Consider something like A*A+A*B*C+D. We would like to 144294285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // reassociate this to A*(A+B*C)+D, which reduces the number of multiplies. 144394285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // To efficiently find this, we count the number of times a factor occurs 144494285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // for any ADD operands that are MULs. 144594285e620b845e09b18939e8d6448e01e692f3ceChris Lattner DenseMap<Value*, unsigned> FactorOccurrences; 1446e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 144794285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // Keep track of each multiply we see, to avoid triggering on (X*4)+(X*4) 144894285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // where they are actually the same multiply. 144994285e620b845e09b18939e8d6448e01e692f3ceChris Lattner unsigned MaxOcc = 0; 145094285e620b845e09b18939e8d6448e01e692f3ceChris Lattner Value *MaxOccVal = 0; 145194285e620b845e09b18939e8d6448e01e692f3ceChris Lattner for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 14520fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands BinaryOperator *BOp = isReassociableOp(Ops[i].Op, Instruction::Mul); 14530fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (!BOp) 145494285e620b845e09b18939e8d6448e01e692f3ceChris Lattner continue; 1455e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 145694285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // Compute all of the factors of this added value. 145794285e620b845e09b18939e8d6448e01e692f3ceChris Lattner SmallVector<Value*, 8> Factors; 14580fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands FindSingleUseMultiplyFactors(BOp, Factors, Ops); 145994285e620b845e09b18939e8d6448e01e692f3ceChris Lattner assert(Factors.size() > 1 && "Bad linearize!"); 1460e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 146194285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // Add one to FactorOccurrences for each unique factor in this op. 14629506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner SmallPtrSet<Value*, 8> Duplicates; 14639506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner for (unsigned i = 0, e = Factors.size(); i != e; ++i) { 14649506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner Value *Factor = Factors[i]; 14659506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner if (!Duplicates.insert(Factor)) continue; 1466e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 14679506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner unsigned Occ = ++FactorOccurrences[Factor]; 14689506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner if (Occ > MaxOcc) { MaxOcc = Occ; MaxOccVal = Factor; } 1469e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 14709506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner // If Factor is a negative constant, add the negated value as a factor 14719506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner // because we can percolate the negate out. Watch for minint, which 14729506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner // cannot be positivified. 14739506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(Factor)) 1474c73b24db5f6226ed44ebc44ce1c25bb357206623Chris Lattner if (CI->isNegative() && !CI->isMinValue(true)) { 14759506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner Factor = ConstantInt::get(CI->getContext(), -CI->getValue()); 14769506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner assert(!Duplicates.count(Factor) && 14779506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner "Shouldn't have two constant factors, missed a canonicalize"); 1478e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 14799506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner unsigned Occ = ++FactorOccurrences[Factor]; 14809506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner if (Occ > MaxOcc) { MaxOcc = Occ; MaxOccVal = Factor; } 14819506c930aa1f7c5fbf1e0e1e6bfae71f4a61ee15Chris Lattner } 148294285e620b845e09b18939e8d6448e01e692f3ceChris Lattner } 148394285e620b845e09b18939e8d6448e01e692f3ceChris Lattner } 1484e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 148594285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // If any factor occurred more than one time, we can pull it out. 148694285e620b845e09b18939e8d6448e01e692f3ceChris Lattner if (MaxOcc > 1) { 148769e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner DEBUG(errs() << "\nFACTORING [" << MaxOcc << "]: " << *MaxOccVal << '\n'); 148894285e620b845e09b18939e8d6448e01e692f3ceChris Lattner ++NumFactor; 148994285e620b845e09b18939e8d6448e01e692f3ceChris Lattner 149094285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // Create a new instruction that uses the MaxOccVal twice. If we don't do 149194285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // this, we could otherwise run into situations where removing a factor 1492e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling // from an expression will drop a use of maxocc, and this can cause 149394285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // RemoveFactorFromExpression on successive values to behave differently. 149494285e620b845e09b18939e8d6448e01e692f3ceChris Lattner Instruction *DummyInst = BinaryOperator::CreateAdd(MaxOccVal, MaxOccVal); 149555e7098bbc363473c01229517097d2a04e04e9b0Bill Wendling SmallVector<WeakVH, 4> NewMulOps; 149637f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands for (unsigned i = 0; i != Ops.size(); ++i) { 1497c2d1b6949c5141d21827cc94daea6ae4b1a9c750Chris Lattner // Only try to remove factors from expressions we're allowed to. 14980fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands BinaryOperator *BOp = isReassociableOp(Ops[i].Op, Instruction::Mul); 14990fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (!BOp) 1500c2d1b6949c5141d21827cc94daea6ae4b1a9c750Chris Lattner continue; 1501e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 150294285e620b845e09b18939e8d6448e01e692f3ceChris Lattner if (Value *V = RemoveFactorFromExpression(Ops[i].Op, MaxOccVal)) { 150337f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands // The factorized operand may occur several times. Convert them all in 150437f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands // one fell swoop. 150537f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands for (unsigned j = Ops.size(); j != i;) { 150637f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands --j; 150737f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands if (Ops[j].Op == Ops[i].Op) { 150837f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands NewMulOps.push_back(V); 150937f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands Ops.erase(Ops.begin()+j); 151037f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands } 151137f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands } 151237f87c7aa914fba1362bb187ce5a386abfe94e39Duncan Sands --i; 151394285e620b845e09b18939e8d6448e01e692f3ceChris Lattner } 151494285e620b845e09b18939e8d6448e01e692f3ceChris Lattner } 1515e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 151694285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // No need for extra uses anymore. 151794285e620b845e09b18939e8d6448e01e692f3ceChris Lattner delete DummyInst; 151854a57045ebcf8e31b1542098d1cd2bda9a718725Duncan Sands 151994285e620b845e09b18939e8d6448e01e692f3ceChris Lattner unsigned NumAddedValues = NewMulOps.size(); 152094285e620b845e09b18939e8d6448e01e692f3ceChris Lattner Value *V = EmitAddTreeOfValues(I, NewMulOps); 152154a57045ebcf8e31b1542098d1cd2bda9a718725Duncan Sands 152269e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // Now that we have inserted the add tree, optimize it. This allows us to 152369e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // handle cases that require multiple factoring steps, such as this: 152494285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // A*A*B + A*A*C --> A*(A*B+A*C) --> A*(A*(B+C)) 15259cd1bc4f8b3e98892a2b9856eccd2a2ec9afdf7fChris Lattner assert(NumAddedValues > 1 && "Each occurrence should contribute a value"); 152654a57045ebcf8e31b1542098d1cd2bda9a718725Duncan Sands (void)NumAddedValues; 1527841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (Instruction *VI = dyn_cast<Instruction>(V)) 1528841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(VI); 152969e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner 153069e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // Create the multiply. 1531841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Instruction *V2 = BinaryOperator::CreateMul(V, MaxOccVal, "tmp", I); 153269e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner 1533f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner // Rerun associate on the multiply in case the inner expression turned into 1534f31e2e92a801c5053dc9b3b484cdec73ad89e567Chris Lattner // a multiply. We want to make sure that we keep things in canonical form. 1535841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(V2); 1536e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 153794285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // If every add operand included the factor (e.g. "A*B + A*C"), then the 153894285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // entire result expression is just the multiply "A*(B+C)". 153994285e620b845e09b18939e8d6448e01e692f3ceChris Lattner if (Ops.empty()) 154094285e620b845e09b18939e8d6448e01e692f3ceChris Lattner return V2; 1541e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 15429cd1bc4f8b3e98892a2b9856eccd2a2ec9afdf7fChris Lattner // Otherwise, we had some input that didn't have the factor, such as 154394285e620b845e09b18939e8d6448e01e692f3ceChris Lattner // "A*B + A*C + D" -> "A*(B+C) + D". Add the new multiply to the list of 15449cd1bc4f8b3e98892a2b9856eccd2a2ec9afdf7fChris Lattner // things being added by this operation. 154594285e620b845e09b18939e8d6448e01e692f3ceChris Lattner Ops.insert(Ops.begin(), ValueEntry(getRank(V2), V2)); 154694285e620b845e09b18939e8d6448e01e692f3ceChris Lattner } 1547e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1548f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner return 0; 1549f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner} 1550e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 1551464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruthnamespace { 1552464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth /// \brief Predicate tests whether a ValueEntry's op is in a map. 1553464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth struct IsValueInMap { 1554464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth const DenseMap<Value *, unsigned> ⤅ 1555464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1556464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth IsValueInMap(const DenseMap<Value *, unsigned> &Map) : Map(Map) {} 1557464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1558464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth bool operator()(const ValueEntry &Entry) { 1559464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return Map.find(Entry.Op) != Map.end(); 1560464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 1561464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth }; 1562464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth} 1563464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1564464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// \brief Build up a vector of value/power pairs factoring a product. 1565464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// 1566464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// Given a series of multiplication operands, build a vector of factors and 1567464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// the powers each is raised to when forming the final product. Sort them in 1568464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// the order of descending power. 1569464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// 1570464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// (x*x) -> [(x, 2)] 1571464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// ((x*x)*x) -> [(x, 3)] 1572464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// ((((x*y)*x)*y)*x) -> [(x, 3), (y, 2)] 1573464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// 1574464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// \returns Whether any factors have a power greater than one. 1575464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruthbool Reassociate::collectMultiplyFactors(SmallVectorImpl<ValueEntry> &Ops, 1576464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVectorImpl<Factor> &Factors) { 15770fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // FIXME: Have Ops be (ValueEntry, Multiplicity) pairs, simplifying this. 15780fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Compute the sum of powers of simplifiable factors. 1579464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth unsigned FactorPowerSum = 0; 15800fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands for (unsigned Idx = 1, Size = Ops.size(); Idx < Size; ++Idx) { 15810fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *Op = Ops[Idx-1].Op; 15820fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 15830fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Count the number of occurrences of this value. 15840fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands unsigned Count = 1; 15850fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands for (; Idx < Size && Ops[Idx].Op == Op; ++Idx) 15860fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands ++Count; 1587464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // Track for simplification all factors which occur 2 or more times. 15880fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (Count > 1) 15890fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands FactorPowerSum += Count; 1590464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 15910fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 1592464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // We can only simplify factors if the sum of the powers of our simplifiable 1593464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // factors is 4 or higher. When that is the case, we will *always* have 1594464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // a simplification. This is an important invariant to prevent cyclicly 1595464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // trying to simplify already minimal formations. 1596464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (FactorPowerSum < 4) 1597464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return false; 1598464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 15990fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Now gather the simplifiable factors, removing them from Ops. 16000fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands FactorPowerSum = 0; 16010fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands for (unsigned Idx = 1; Idx < Ops.size(); ++Idx) { 16020fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Value *Op = Ops[Idx-1].Op; 1603464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 16040fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // Count the number of occurrences of this value. 16050fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands unsigned Count = 1; 16060fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands for (; Idx < Ops.size() && Ops[Idx].Op == Op; ++Idx) 16070fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands ++Count; 16080fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands if (Count == 1) 16090fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands continue; 1610d9b0b025612992a0b724eeca8bdf10b1d7a5c355Benjamin Kramer // Move an even number of occurrences to Factors. 16110fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Count &= ~1U; 16120fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Idx -= Count; 16130fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands FactorPowerSum += Count; 16140fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Factors.push_back(Factor(Op, Count)); 16150fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands Ops.erase(Ops.begin()+Idx, Ops.begin()+Idx+Count); 1616464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 16170fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 1618464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // None of the adjustments above should have reduced the sum of factor powers 1619464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // below our mininum of '4'. 1620464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth assert(FactorPowerSum >= 4); 1621464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1622464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth std::sort(Factors.begin(), Factors.end(), Factor::PowerDescendingSorter()); 1623464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return true; 1624464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth} 1625464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1626464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// \brief Build a tree of multiplies, computing the product of Ops. 1627464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruthstatic Value *buildMultiplyTree(IRBuilder<> &Builder, 1628464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVectorImpl<Value*> &Ops) { 1629464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (Ops.size() == 1) 1630464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return Ops.back(); 1631464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1632464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Value *LHS = Ops.pop_back_val(); 1633464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth do { 1634464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth LHS = Builder.CreateMul(LHS, Ops.pop_back_val()); 1635464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } while (!Ops.empty()); 1636464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1637464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return LHS; 1638464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth} 1639464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1640464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// \brief Build a minimal multiplication DAG for (a^x)*(b^y)*(c^z)*... 1641464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// 1642464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// Given a vector of values raised to various powers, where no two values are 1643464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// equal and the powers are sorted in decreasing order, compute the minimal 1644464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// DAG of multiplies to compute the final product, and return that product 1645464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth/// value. 1646464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler CarruthValue *Reassociate::buildMinimalMultiplyDAG(IRBuilder<> &Builder, 1647464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVectorImpl<Factor> &Factors) { 1648464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth assert(Factors[0].Power); 1649464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVector<Value *, 4> OuterProduct; 1650464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth for (unsigned LastIdx = 0, Idx = 1, Size = Factors.size(); 1651464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Idx < Size && Factors[Idx].Power > 0; ++Idx) { 1652464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (Factors[Idx].Power != Factors[LastIdx].Power) { 1653464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth LastIdx = Idx; 1654464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth continue; 1655464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 1656464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1657464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // We want to multiply across all the factors with the same power so that 1658464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // we can raise them to that power as a single entity. Build a mini tree 1659464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // for that. 1660464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVector<Value *, 4> InnerProduct; 1661464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth InnerProduct.push_back(Factors[LastIdx].Base); 1662464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth do { 1663464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth InnerProduct.push_back(Factors[Idx].Base); 1664464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth ++Idx; 1665464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } while (Idx < Size && Factors[Idx].Power == Factors[LastIdx].Power); 1666464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1667464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // Reset the base value of the first factor to the new expression tree. 1668464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // We'll remove all the factors with the same power in a second pass. 1669841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Value *M = Factors[LastIdx].Base = buildMultiplyTree(Builder, InnerProduct); 1670841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (Instruction *MI = dyn_cast<Instruction>(M)) 1671841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(MI); 1672464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1673464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth LastIdx = Idx; 1674464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 1675464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // Unique factors with equal powers -- we've folded them into the first one's 1676464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // base. 1677464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Factors.erase(std::unique(Factors.begin(), Factors.end(), 1678464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Factor::PowerEqual()), 1679464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Factors.end()); 1680464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1681464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // Iteratively collect the base of each factor with an add power into the 1682464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // outer product, and halve each power in preparation for squaring the 1683464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // expression. 1684464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth for (unsigned Idx = 0, Size = Factors.size(); Idx != Size; ++Idx) { 1685464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (Factors[Idx].Power & 1) 1686464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth OuterProduct.push_back(Factors[Idx].Base); 1687464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Factors[Idx].Power >>= 1; 1688464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 1689464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (Factors[0].Power) { 1690464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Value *SquareRoot = buildMinimalMultiplyDAG(Builder, Factors); 1691464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth OuterProduct.push_back(SquareRoot); 1692464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth OuterProduct.push_back(SquareRoot); 1693464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth } 1694464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (OuterProduct.size() == 1) 1695464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return OuterProduct.front(); 1696464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1697a33701098936ffba12326d96e98d388357f3e098Duncan Sands Value *V = buildMultiplyTree(Builder, OuterProduct); 1698a33701098936ffba12326d96e98d388357f3e098Duncan Sands return V; 1699464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth} 1700464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1701464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler CarruthValue *Reassociate::OptimizeMul(BinaryOperator *I, 1702464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVectorImpl<ValueEntry> &Ops) { 1703464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // We can only optimize the multiplies when there is a chain of more than 1704464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // three, such that a balanced tree might require fewer total multiplies. 1705464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (Ops.size() < 4) 1706464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return 0; 1707464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1708464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // Try to turn linear trees of multiplies without other uses of the 1709464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // intermediate stages into minimal multiply DAGs with perfect sub-expression 1710464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth // re-use. 1711464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth SmallVector<Factor, 4> Factors; 1712464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (!collectMultiplyFactors(Ops, Factors)) 1713464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return 0; // All distinct factors, so nothing left for us to do. 1714464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1715464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth IRBuilder<> Builder(I); 1716464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Value *V = buildMinimalMultiplyDAG(Builder, Factors); 1717464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (Ops.empty()) 1718464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return V; 1719464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1720464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth ValueEntry NewEntry = ValueEntry(getRank(V), V); 1721464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth Ops.insert(std::lower_bound(Ops.begin(), Ops.end(), NewEntry), NewEntry); 1722464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return 0; 1723464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth} 1724464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth 1725e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris LattnerValue *Reassociate::OptimizeExpression(BinaryOperator *I, 17269f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner SmallVectorImpl<ValueEntry> &Ops) { 1727469001000620df176decd093a300db84a06cc78bChris Lattner // Now that we have the linearized expression tree, try to optimize it. 1728469001000620df176decd093a300db84a06cc78bChris Lattner // Start by folding any constants that we found. 17297ecfcc163956a9e27845ac217f6c650658631030Duncan Sands Constant *Cst = 0; 1730e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner unsigned Opcode = I->getOpcode(); 17317ecfcc163956a9e27845ac217f6c650658631030Duncan Sands while (!Ops.empty() && isa<Constant>(Ops.back().Op)) { 17327ecfcc163956a9e27845ac217f6c650658631030Duncan Sands Constant *C = cast<Constant>(Ops.pop_back_val().Op); 17337ecfcc163956a9e27845ac217f6c650658631030Duncan Sands Cst = Cst ? ConstantExpr::get(Opcode, C, Cst) : C; 17347ecfcc163956a9e27845ac217f6c650658631030Duncan Sands } 17357ecfcc163956a9e27845ac217f6c650658631030Duncan Sands // If there was nothing but constants then we are done. 17367ecfcc163956a9e27845ac217f6c650658631030Duncan Sands if (Ops.empty()) 17377ecfcc163956a9e27845ac217f6c650658631030Duncan Sands return Cst; 17387ecfcc163956a9e27845ac217f6c650658631030Duncan Sands 17397ecfcc163956a9e27845ac217f6c650658631030Duncan Sands // Put the combined constant back at the end of the operand list, except if 17407ecfcc163956a9e27845ac217f6c650658631030Duncan Sands // there is no point. For example, an add of 0 gets dropped here, while a 17417ecfcc163956a9e27845ac217f6c650658631030Duncan Sands // multiplication by zero turns the whole expression into zero. 17427ecfcc163956a9e27845ac217f6c650658631030Duncan Sands if (Cst && Cst != ConstantExpr::getBinOpIdentity(Opcode, I->getType())) { 17437ecfcc163956a9e27845ac217f6c650658631030Duncan Sands if (Cst == ConstantExpr::getBinOpAbsorber(Opcode, I->getType())) 17447ecfcc163956a9e27845ac217f6c650658631030Duncan Sands return Cst; 17457ecfcc163956a9e27845ac217f6c650658631030Duncan Sands Ops.push_back(ValueEntry(0, Cst)); 17467ecfcc163956a9e27845ac217f6c650658631030Duncan Sands } 17477ecfcc163956a9e27845ac217f6c650658631030Duncan Sands 17487ecfcc163956a9e27845ac217f6c650658631030Duncan Sands if (Ops.size() == 1) return Ops[0].Op; 1749e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1750ec531233a16605756a84d175178e1ee0fac4791cChris Lattner // Handle destructive annihilation due to identities between elements in the 1751469001000620df176decd093a300db84a06cc78bChris Lattner // argument list here. 1752464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth unsigned NumOps = Ops.size(); 1753109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner switch (Opcode) { 1754109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner default: break; 1755109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner case Instruction::And: 1756109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner case Instruction::Or: 1757f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner if (Value *Result = OptimizeAndOrXor(Opcode, Ops)) 1758f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner return Result; 1759109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner break; 1760109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner 17612d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang case Instruction::Xor: 17622d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang if (Value *Result = OptimizeXor(I, Ops)) 17632d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang return Result; 17642d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang break; 17652d1001064989b7fa79507816fc17d467fc00a2f2Shuxin Yang 1766464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth case Instruction::Add: 176794285e620b845e09b18939e8d6448e01e692f3ceChris Lattner if (Value *Result = OptimizeAdd(I, Ops)) 1768f3f55a9bc1ce62fad7faecff7bd83565d569dee8Chris Lattner return Result; 1769464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth break; 1770e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 1771464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth case Instruction::Mul: 1772464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth if (Value *Result = OptimizeMul(I, Ops)) 1773464bda3a167bb761eb3c9c178db3fa8ed26fe825Chandler Carruth return Result; 1774109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner break; 1775109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 1776109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner 1777841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (Ops.size() != NumOps) 1778e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return OptimizeExpression(I, Ops); 1779e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return 0; 1780469001000620df176decd093a300db84a06cc78bChris Lattner} 1781469001000620df176decd093a300db84a06cc78bChris Lattner 17824df2826166f1339eb7ddf5c5c84565fccb794de8Shuxin Yang/// EraseInst - Zap the given instruction, adding interesting operands to the 17834df2826166f1339eb7ddf5c5c84565fccb794de8Shuxin Yang/// work list. 17844df2826166f1339eb7ddf5c5c84565fccb794de8Shuxin Yangvoid Reassociate::EraseInst(Instruction *I) { 1785841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands assert(isInstructionTriviallyDead(I) && "Trivially dead instructions only!"); 1786841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end()); 1787841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // Erase the dead instruction. 1788841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands ValueRankMap.erase(I); 17894df2826166f1339eb7ddf5c5c84565fccb794de8Shuxin Yang RedoInsts.remove(I); 1790841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands I->eraseFromParent(); 1791841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // Optimize its operands. 1792cd117f736c47947af5c6549734549e135e626c5cDuncan Sands SmallPtrSet<Instruction *, 8> Visited; // Detect self-referential nodes. 1793841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands for (unsigned i = 0, e = Ops.size(); i != e; ++i) 1794841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (Instruction *Op = dyn_cast<Instruction>(Ops[i])) { 1795841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // If this is a node in an expression tree, climb to the expression root 1796841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // and add that since that's where optimization actually happens. 1797841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands unsigned Opcode = Op->getOpcode(); 1798cd117f736c47947af5c6549734549e135e626c5cDuncan Sands while (Op->hasOneUse() && Op->use_back()->getOpcode() == Opcode && 1799cd117f736c47947af5c6549734549e135e626c5cDuncan Sands Visited.insert(Op)) 1800841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Op = Op->use_back(); 18014df2826166f1339eb7ddf5c5c84565fccb794de8Shuxin Yang RedoInsts.insert(Op); 1802841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands } 1803841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands} 1804841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands 1805841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands/// OptimizeInst - Inspect and optimize the given instruction. Note that erasing 1806841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands/// instructions is not allowed. 1807841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sandsvoid Reassociate::OptimizeInst(Instruction *I) { 1808841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // Only consider operations that we understand. 1809841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (!isa<BinaryOperator>(I)) 1810841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands return; 1811841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands 1812841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (I->getOpcode() == Instruction::Shl && 1813841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands isa<ConstantInt>(I->getOperand(1))) 1814841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // If an operand of this shift is a reassociable multiply, or if the shift 1815841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // is used by a reassociable multiply or add, turn into a multiply. 1816841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (isReassociableOp(I->getOperand(0), Instruction::Mul) || 1817841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands (I->hasOneUse() && 1818841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands (isReassociableOp(I->use_back(), Instruction::Mul) || 1819841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands isReassociableOp(I->use_back(), Instruction::Add)))) { 1820841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Instruction *NI = ConvertShiftToMul(I); 1821841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(I); 1822dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman MadeChange = true; 1823841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands I = NI; 1824dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman } 1825641f02f10f08c9a9add651c6f0169f5441eaeb49Chris Lattner 1826423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson // Floating point binary operators are not associative, but we can still 1827423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson // commute (some) of them, to canonicalize the order of their operands. 1828423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson // This can potentially expose more CSE opportunities, and makes writing 1829423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson // other transformations simpler. 1830841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if ((I->getType()->isFloatingPointTy() || I->getType()->isVectorTy())) { 1831423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson // FAdd and FMul can be commuted. 1832841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (I->getOpcode() != Instruction::FMul && 1833841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands I->getOpcode() != Instruction::FAdd) 1834423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson return; 1835423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson 1836841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Value *LHS = I->getOperand(0); 1837841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Value *RHS = I->getOperand(1); 1838423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson unsigned LHSRank = getRank(LHS); 1839423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson unsigned RHSRank = getRank(RHS); 1840423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson 1841423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson // Sort the operands by rank. 1842423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson if (RHSRank < LHSRank) { 1843841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands I->setOperand(0, RHS); 1844841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands I->setOperand(1, LHS); 1845423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson } 1846423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson 1847423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson return; 1848423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson } 1849423f19f2dadee9325766008b63c1faf3c644043bOwen Anderson 1850dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // Do not reassociate boolean (i1) expressions. We want to preserve the 1851dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // original order of evaluation for short-circuited comparisons that 1852dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // SimplifyCFG has folded to AND/OR expressions. If the expression 1853dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // is not further optimized, it is likely to be transformed back to a 1854dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // short-circuited form for code gen, and the source order may have been 1855dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // optimized for the most likely conditions. 1856841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (I->getType()->isIntegerTy(1)) 1857dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman return; 1858fc375d22001d27ba6d22db67821da057e36f7f89Bob Wilson 1859dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // If this is a subtract instruction which is not already in negate form, 1860dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // see if we can convert it to X+-Y. 1861841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (I->getOpcode() == Instruction::Sub) { 1862841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (ShouldBreakUpSubtract(I)) { 1863841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Instruction *NI = BreakUpSubtract(I); 1864841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(I); 1865dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman MadeChange = true; 1866841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands I = NI; 1867841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands } else if (BinaryOperator::isNeg(I)) { 1868dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // Otherwise, this is a negation. See if the operand is a multiply tree 1869dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // and if this is not an inner node of a multiply tree. 1870841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (isReassociableOp(I->getOperand(1), Instruction::Mul) && 1871841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands (!I->hasOneUse() || 1872841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands !isReassociableOp(I->use_back(), Instruction::Mul))) { 1873841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands Instruction *NI = LowerNegateToMultiply(I); 1874841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(I); 1875d5b8d92b9f4dfb216e4f2a52b4e801d7559574baChris Lattner MadeChange = true; 1876841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands I = NI; 187708b43921e18f314c4fd38049291d323830934c36Chris Lattner } 1878f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner } 1879dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman } 1880e4b730441dab4aff9a69aeddbdea98990e7703c4Chris Lattner 1881841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // If this instruction is an associative binary operator, process it. 1882841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (!I->isAssociative()) return; 1883841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands BinaryOperator *BO = cast<BinaryOperator>(I); 188400b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 1885dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // If this is an interior node of a reassociable tree, ignore it until we 1886dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // get to the root of the tree, to avoid N^2 analysis. 1887c1deb67d78ac987577e9caa22d60435239ad0e12Nadav Rotem unsigned Opcode = BO->getOpcode(); 1888c1deb67d78ac987577e9caa22d60435239ad0e12Nadav Rotem if (BO->hasOneUse() && BO->use_back()->getOpcode() == Opcode) 1889dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman return; 1890c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 1891e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling // If this is an add tree that is used by a sub instruction, ignore it 1892dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman // until we process the subtract. 1893841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (BO->hasOneUse() && BO->getOpcode() == Instruction::Add && 1894841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands cast<Instruction>(BO->use_back())->getOpcode() == Instruction::Sub) 1895dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman return; 18967b4ad94282b94e1827be29b4db73fdf6e241f748Chris Lattner 1897841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands ReassociateExpression(BO); 1898895b392269cad07c34d59110d68dc86708c53adbChris Lattner} 1899c9fd097a01383323f166c14c17d3984620cad766Chris Lattner 1900cd117f736c47947af5c6549734549e135e626c5cDuncan Sandsvoid Reassociate::ReassociateExpression(BinaryOperator *I) { 1901e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 190269e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // First, walk the expression tree, linearizing the tree, collecting the 190369e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // operand information. 1904c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands SmallVector<RepeatedValue, 8> Tree; 1905c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands MadeChange |= LinearizeExprTree(I, Tree); 19069f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner SmallVector<ValueEntry, 8> Ops; 1907c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Ops.reserve(Tree.size()); 1908c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands for (unsigned i = 0, e = Tree.size(); i != e; ++i) { 1909c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands RepeatedValue E = Tree[i]; 1910c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands Ops.append(E.second.getZExtValue(), 1911c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands ValueEntry(getRank(E.first), E.first)); 1912c038a7833565ecf92a699371d448135a097c9e2fDuncan Sands } 1913e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 191424dfa52fa20eee39440e5dec4d23359e5a6773c7Duncan Sands DEBUG(dbgs() << "RAIn:\t"; PrintOps(I, Ops); dbgs() << '\n'); 191524dfa52fa20eee39440e5dec4d23359e5a6773c7Duncan Sands 1916895b392269cad07c34d59110d68dc86708c53adbChris Lattner // Now that we have linearized the tree to a list and have gathered all of 1917895b392269cad07c34d59110d68dc86708c53adbChris Lattner // the operands and their ranks, sort the operands by their rank. Use a 1918895b392269cad07c34d59110d68dc86708c53adbChris Lattner // stable_sort so that values with equal ranks will have their relative 1919895b392269cad07c34d59110d68dc86708c53adbChris Lattner // positions maintained (and so the compiler is deterministic). Note that 1920895b392269cad07c34d59110d68dc86708c53adbChris Lattner // this sorts so that the highest ranking values end up at the beginning of 1921895b392269cad07c34d59110d68dc86708c53adbChris Lattner // the vector. 1922895b392269cad07c34d59110d68dc86708c53adbChris Lattner std::stable_sort(Ops.begin(), Ops.end()); 1923e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1924895b392269cad07c34d59110d68dc86708c53adbChris Lattner // OptimizeExpression - Now that we have the expression tree in a convenient 1925895b392269cad07c34d59110d68dc86708c53adbChris Lattner // sorted form, optimize it globally if possible. 1926895b392269cad07c34d59110d68dc86708c53adbChris Lattner if (Value *V = OptimizeExpression(I, Ops)) { 1927cd117f736c47947af5c6549734549e135e626c5cDuncan Sands if (V == I) 1928cd117f736c47947af5c6549734549e135e626c5cDuncan Sands // Self-referential expression in unreachable code. 1929cd117f736c47947af5c6549734549e135e626c5cDuncan Sands return; 1930895b392269cad07c34d59110d68dc86708c53adbChris Lattner // This expression tree simplified to something that isn't a tree, 1931895b392269cad07c34d59110d68dc86708c53adbChris Lattner // eliminate it. 1932a1fa76cb5443e7b0fe7d36ee1118f80050e746f9David Greene DEBUG(dbgs() << "Reassoc to scalar: " << *V << '\n'); 1933895b392269cad07c34d59110d68dc86708c53adbChris Lattner I->replaceAllUsesWith(V); 19345367b23f76e75ebb680956575346fa8c3d56780fDevang Patel if (Instruction *VI = dyn_cast<Instruction>(V)) 19355367b23f76e75ebb680956575346fa8c3d56780fDevang Patel VI->setDebugLoc(I->getDebugLoc()); 1936841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(I); 19379fdaefad580194353f34b6d72669591f8f9d811aChris Lattner ++NumAnnihil; 1938cd117f736c47947af5c6549734549e135e626c5cDuncan Sands return; 1939895b392269cad07c34d59110d68dc86708c53adbChris Lattner } 1940e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1941895b392269cad07c34d59110d68dc86708c53adbChris Lattner // We want to sink immediates as deeply as possible except in the case where 1942895b392269cad07c34d59110d68dc86708c53adbChris Lattner // this is a multiply tree used only by an add, and the immediate is a -1. 1943895b392269cad07c34d59110d68dc86708c53adbChris Lattner // In this case we reassociate to put the negation on the outside so that we 1944895b392269cad07c34d59110d68dc86708c53adbChris Lattner // can fold the negation into the add: (-X)*Y + Z -> Z-X*Y 1945895b392269cad07c34d59110d68dc86708c53adbChris Lattner if (I->getOpcode() == Instruction::Mul && I->hasOneUse() && 1946895b392269cad07c34d59110d68dc86708c53adbChris Lattner cast<Instruction>(I->use_back())->getOpcode() == Instruction::Add && 1947895b392269cad07c34d59110d68dc86708c53adbChris Lattner isa<ConstantInt>(Ops.back().Op) && 1948895b392269cad07c34d59110d68dc86708c53adbChris Lattner cast<ConstantInt>(Ops.back().Op)->isAllOnesValue()) { 19499f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner ValueEntry Tmp = Ops.pop_back_val(); 19509f7b7089be854c323f8d9a4627d80e47adf496e6Chris Lattner Ops.insert(Ops.begin(), Tmp); 1951895b392269cad07c34d59110d68dc86708c53adbChris Lattner } 1952e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1953a1fa76cb5443e7b0fe7d36ee1118f80050e746f9David Greene DEBUG(dbgs() << "RAOut:\t"; PrintOps(I, Ops); dbgs() << '\n'); 1954e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 1955895b392269cad07c34d59110d68dc86708c53adbChris Lattner if (Ops.size() == 1) { 1956cd117f736c47947af5c6549734549e135e626c5cDuncan Sands if (Ops[0].Op == I) 1957cd117f736c47947af5c6549734549e135e626c5cDuncan Sands // Self-referential expression in unreachable code. 1958cd117f736c47947af5c6549734549e135e626c5cDuncan Sands return; 1959cd117f736c47947af5c6549734549e135e626c5cDuncan Sands 1960895b392269cad07c34d59110d68dc86708c53adbChris Lattner // This expression tree simplified to something that isn't a tree, 1961895b392269cad07c34d59110d68dc86708c53adbChris Lattner // eliminate it. 1962895b392269cad07c34d59110d68dc86708c53adbChris Lattner I->replaceAllUsesWith(Ops[0].Op); 19635367b23f76e75ebb680956575346fa8c3d56780fDevang Patel if (Instruction *OI = dyn_cast<Instruction>(Ops[0].Op)) 19645367b23f76e75ebb680956575346fa8c3d56780fDevang Patel OI->setDebugLoc(I->getDebugLoc()); 1965841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands RedoInsts.insert(I); 1966cd117f736c47947af5c6549734549e135e626c5cDuncan Sands return; 19674fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner } 1968e8cd3f249133406c9b2a8dc6b6dbd2752fc605b4Bill Wendling 196969e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // Now that we ordered and optimized the expressions, splat them back into 197069e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner // the expression tree, removing any unneeded nodes. 197169e98e2c0f7a1a1a8e3547b57e3e78e1142b8a64Chris Lattner RewriteExprTree(I, Ops); 19724fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 19734fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 19747e70829632f82de15db187845666aaca6e04b792Chris Lattnerbool Reassociate::runOnFunction(Function &F) { 1975841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // Calculate the rank map for F 19764fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner BuildRankMap(F); 19774fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 1978c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner MadeChange = false; 1979841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) { 1980841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // Optimize every instruction in the basic block. 1981841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE; ) 1982841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (isInstructionTriviallyDead(II)) { 1983841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands EraseInst(II++); 1984841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands } else { 1985841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands OptimizeInst(II); 1986841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands assert(II->getParent() == BI && "Moved to a different block!"); 1987841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands ++II; 1988841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands } 1989841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands 1990841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands // If this produced extra instructions to optimize, handle them now. 1991841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands while (!RedoInsts.empty()) { 19924df2826166f1339eb7ddf5c5c84565fccb794de8Shuxin Yang Instruction *I = RedoInsts.pop_back_val(); 1993841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands if (isInstructionTriviallyDead(I)) 1994841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands EraseInst(I); 1995841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands else 1996841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands OptimizeInst(I); 1997dac5dbadeb840ddded4665d144f31c5f88494d6eDan Gohman } 1998841f42617531ff947b2d957e7b0cb367a290aae4Duncan Sands } 19994fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 20000fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands // We are done with the rank map. 20010fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands RankMap.clear(); 20020fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands ValueRankMap.clear(); 20030fd120b970fe9a036ae664ad1bfbf04e55b3b8a7Duncan Sands 2004c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner return MadeChange; 20054fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 2006