Reassociate.cpp revision 3e8b6631e67e01e4960a7ba4668a50c596607473
14fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner//===- 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 11e96fda3002dd0769d3dd758ac5008ba8cda92349Chris Lattner// to promote better constant propagation, GCSE, LICM, PRE... 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" 250975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner#include "llvm/Constants.h" 26ae74f555522298bef3be8a173163bf778d59adf9Chris Lattner#include "llvm/DerivedTypes.h" 274fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner#include "llvm/Function.h" 28d8e1eea678833cc2b15e4ea69a5a403ba9c3b013Misha Brukman#include "llvm/Instructions.h" 2903afd02ca2486aebb3b29edd2f77920d4e5020fdDale Johannesen#include "llvm/IntrinsicInst.h" 30fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson#include "llvm/LLVMContext.h" 314fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner#include "llvm/Pass.h" 32c9fd097a01383323f166c14c17d3984620cad766Chris Lattner#include "llvm/Assembly/Writer.h" 334fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner#include "llvm/Support/CFG.h" 34551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/Debug.h" 35d3c7b7359d4992b9ab9f8e12ccd0a9b7d2446566Chris Lattner#include "llvm/Support/ValueHandle.h" 36bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner#include "llvm/Support/raw_ostream.h" 37551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/PostOrderIterator.h" 38551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/Statistic.h" 39c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner#include <algorithm> 40c9235d2e855c56e9aa157969f8132a05f9ba89d8Dan Gohman#include <map> 41d7456026629fc1760a45e6e955e9834246493147Chris Lattnerusing namespace llvm; 42d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 430e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumLinear , "Number of insts linearized"); 440e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumChanged, "Number of insts reassociated"); 450e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumAnnihil, "Number of expr tree annihilated"); 460e5f499638c8d277b9dc4a4385712177c53b5681Chris LattnerSTATISTIC(NumFactor , "Number of multiplies factored"); 47a92f696b74a99325026ebbdbffd2a44317e0c10bChris Lattner 480e5f499638c8d277b9dc4a4385712177c53b5681Chris Lattnernamespace { 493e8b6631e67e01e4960a7ba4668a50c596607473Chris Lattner struct ValueEntry { 50c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner unsigned Rank; 51c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner Value *Op; 52c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner ValueEntry(unsigned R, Value *O) : Rank(R), Op(O) {} 53c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner }; 54c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner inline bool operator<(const ValueEntry &LHS, const ValueEntry &RHS) { 55c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner return LHS.Rank > RHS.Rank; // Sort so that highest rank goes to start. 56c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } 57e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 58c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 5950cacb2a520b93530e79220a307c907163b9e370Devang Patel#ifndef NDEBUG 60e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// PrintOps - Print out the expression identified in the Ops list. 61e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// 62e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattnerstatic void PrintOps(Instruction *I, const std::vector<ValueEntry> &Ops) { 63e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Module *M = I->getParent()->getParent()->getParent(); 6479c5d3f9717756dc3ff56cfcaa3ae1a5930c457aChris Lattner errs() << Instruction::getOpcodeName(I->getOpcode()) << " " 657de3b5db26bb3c8dcca5348fb7c0be4f9bd1bcb7Chris Lattner << *Ops[0].Op->getType(); 667de3b5db26bb3c8dcca5348fb7c0be4f9bd1bcb7Chris Lattner for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 6779c5d3f9717756dc3ff56cfcaa3ae1a5930c457aChris Lattner WriteAsOperand(errs() << " ", Ops[i].Op, false, M); 6879c5d3f9717756dc3ff56cfcaa3ae1a5930c457aChris Lattner errs() << "," << Ops[i].Rank; 697de3b5db26bb3c8dcca5348fb7c0be4f9bd1bcb7Chris Lattner } 70e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 7159500c8f9a76b3386329b6f837255c16f4e8b61bDevang Patel#endif 72e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 73844731a7f1909f55935e3514c9e713a62d67662eDan Gohmannamespace { 743e8b6631e67e01e4960a7ba4668a50c596607473Chris Lattner class Reassociate : public FunctionPass { 750c0edf8afc35a42b15a24ebb5fa5f3fc674290aeChris Lattner std::map<BasicBlock*, unsigned> RankMap; 76d3c7b7359d4992b9ab9f8e12ccd0a9b7d2446566Chris Lattner std::map<AssertingVH<>, unsigned> ValueRankMap; 77c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner bool MadeChange; 784fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner public: 79ecd94c804a563f2a86572dcf1d2e81f397e19daaNick Lewycky static char ID; // Pass identification, replacement for typeid 80ae73dc1448d25b02cabc7c64c86c64371453dda8Dan Gohman Reassociate() : FunctionPass(&ID) {} 81794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel 827e70829632f82de15db187845666aaca6e04b792Chris Lattner bool runOnFunction(Function &F); 834fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 844fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner virtual void getAnalysisUsage(AnalysisUsage &AU) const { 85cb2610ea037a17115ef3a01a6bdaab4e3cfdca27Chris Lattner AU.setPreservesCFG(); 864fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner } 874fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner private: 887e70829632f82de15db187845666aaca6e04b792Chris Lattner void BuildRankMap(Function &F); 894fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner unsigned getRank(Value *V); 90895b392269cad07c34d59110d68dc86708c53adbChris Lattner void ReassociateExpression(BinaryOperator *I); 91e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner void RewriteExprTree(BinaryOperator *I, std::vector<ValueEntry> &Ops, 92e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner unsigned Idx = 0); 93e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *OptimizeExpression(BinaryOperator *I, std::vector<ValueEntry> &Ops); 94c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner void LinearizeExprTree(BinaryOperator *I, std::vector<ValueEntry> &Ops); 95c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner void LinearizeExpr(BinaryOperator *I); 96e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *RemoveFactorFromExpression(Value *V, Value *Factor); 97c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner void ReassociateBB(BasicBlock *BB); 98e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 99e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner void RemoveDeadBinaryOp(Value *V); 1004fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner }; 1014fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 1024fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 103844731a7f1909f55935e3514c9e713a62d67662eDan Gohmanchar Reassociate::ID = 0; 104844731a7f1909f55935e3514c9e713a62d67662eDan Gohmanstatic RegisterPass<Reassociate> X("reassociate", "Reassociate expressions"); 105844731a7f1909f55935e3514c9e713a62d67662eDan Gohman 106d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke// Public interface to the Reassociate pass 107d7456026629fc1760a45e6e955e9834246493147Chris LattnerFunctionPass *llvm::createReassociatePass() { return new Reassociate(); } 1084fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 109e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattnervoid Reassociate::RemoveDeadBinaryOp(Value *V) { 110e4d87aa2de6e52952dca73716386db09aad5a8fdReid Spencer Instruction *Op = dyn_cast<Instruction>(V); 111e4d87aa2de6e52952dca73716386db09aad5a8fdReid Spencer if (!Op || !isa<BinaryOperator>(Op) || !isa<CmpInst>(Op) || !Op->use_empty()) 112e4d87aa2de6e52952dca73716386db09aad5a8fdReid Spencer return; 113e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 114e4d87aa2de6e52952dca73716386db09aad5a8fdReid Spencer Value *LHS = Op->getOperand(0), *RHS = Op->getOperand(1); 115e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner RemoveDeadBinaryOp(LHS); 116e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner RemoveDeadBinaryOp(RHS); 117e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 118e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 1199c723199384b16899831937e2800d52f4f953569Chris Lattner 1209c723199384b16899831937e2800d52f4f953569Chris Lattnerstatic bool isUnmovableInstruction(Instruction *I) { 1219c723199384b16899831937e2800d52f4f953569Chris Lattner if (I->getOpcode() == Instruction::PHI || 1229c723199384b16899831937e2800d52f4f953569Chris Lattner I->getOpcode() == Instruction::Alloca || 1239c723199384b16899831937e2800d52f4f953569Chris Lattner I->getOpcode() == Instruction::Load || 1249c723199384b16899831937e2800d52f4f953569Chris Lattner I->getOpcode() == Instruction::Malloc || 1259c723199384b16899831937e2800d52f4f953569Chris Lattner I->getOpcode() == Instruction::Invoke || 12603afd02ca2486aebb3b29edd2f77920d4e5020fdDale Johannesen (I->getOpcode() == Instruction::Call && 12703afd02ca2486aebb3b29edd2f77920d4e5020fdDale Johannesen !isa<DbgInfoIntrinsic>(I)) || 1281628cec4d7fce310d9cde0bcc73997e5a71692c4Reid Spencer I->getOpcode() == Instruction::UDiv || 1291628cec4d7fce310d9cde0bcc73997e5a71692c4Reid Spencer I->getOpcode() == Instruction::SDiv || 1301628cec4d7fce310d9cde0bcc73997e5a71692c4Reid Spencer I->getOpcode() == Instruction::FDiv || 1310a783f783ca05c961234385f5b269d4cf03dbbdbReid Spencer I->getOpcode() == Instruction::URem || 1320a783f783ca05c961234385f5b269d4cf03dbbdbReid Spencer I->getOpcode() == Instruction::SRem || 1330a783f783ca05c961234385f5b269d4cf03dbbdbReid Spencer I->getOpcode() == Instruction::FRem) 1349c723199384b16899831937e2800d52f4f953569Chris Lattner return true; 1359c723199384b16899831937e2800d52f4f953569Chris Lattner return false; 1369c723199384b16899831937e2800d52f4f953569Chris Lattner} 1379c723199384b16899831937e2800d52f4f953569Chris Lattner 1387e70829632f82de15db187845666aaca6e04b792Chris Lattnervoid Reassociate::BuildRankMap(Function &F) { 1396007cb6c4d923e2dee4a1133fb6d1bb00a37062dChris Lattner unsigned i = 2; 140fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner 141fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner // Assign distinct ranks to function arguments 142e4d5c441e04bdc00ccf1804744af670655123b07Chris Lattner for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I) 143d3c7b7359d4992b9ab9f8e12ccd0a9b7d2446566Chris Lattner ValueRankMap[&*I] = ++i; 144fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner 1457e70829632f82de15db187845666aaca6e04b792Chris Lattner ReversePostOrderTraversal<Function*> RPOT(&F); 1464fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner for (ReversePostOrderTraversal<Function*>::rpo_iterator I = RPOT.begin(), 1479c723199384b16899831937e2800d52f4f953569Chris Lattner E = RPOT.end(); I != E; ++I) { 1489c723199384b16899831937e2800d52f4f953569Chris Lattner BasicBlock *BB = *I; 1499c723199384b16899831937e2800d52f4f953569Chris Lattner unsigned BBRank = RankMap[BB] = ++i << 16; 1509c723199384b16899831937e2800d52f4f953569Chris Lattner 1519c723199384b16899831937e2800d52f4f953569Chris Lattner // Walk the basic block, adding precomputed ranks for any instructions that 1529c723199384b16899831937e2800d52f4f953569Chris Lattner // we cannot move. This ensures that the ranks for these instructions are 1539c723199384b16899831937e2800d52f4f953569Chris Lattner // all different in the block. 1549c723199384b16899831937e2800d52f4f953569Chris Lattner for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1559c723199384b16899831937e2800d52f4f953569Chris Lattner if (isUnmovableInstruction(I)) 156d3c7b7359d4992b9ab9f8e12ccd0a9b7d2446566Chris Lattner ValueRankMap[&*I] = ++BBRank; 1579c723199384b16899831937e2800d52f4f953569Chris Lattner } 1584fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 1594fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 1604fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattnerunsigned Reassociate::getRank(Value *V) { 161fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner if (isa<Argument>(V)) return ValueRankMap[V]; // Function argument... 162fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner 16308b43921e18f314c4fd38049291d323830934c36Chris Lattner Instruction *I = dyn_cast<Instruction>(V); 16408b43921e18f314c4fd38049291d323830934c36Chris Lattner if (I == 0) return 0; // Otherwise it's a global or constant, rank 0. 1654fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 16608b43921e18f314c4fd38049291d323830934c36Chris Lattner unsigned &CachedRank = ValueRankMap[I]; 16708b43921e18f314c4fd38049291d323830934c36Chris Lattner if (CachedRank) return CachedRank; // Rank already known? 16800b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 16908b43921e18f314c4fd38049291d323830934c36Chris Lattner // If this is an expression, return the 1+MAX(rank(LHS), rank(RHS)) so that 17008b43921e18f314c4fd38049291d323830934c36Chris Lattner // we can reassociate expressions for code motion! Since we do not recurse 17108b43921e18f314c4fd38049291d323830934c36Chris Lattner // for PHI nodes, we cannot have infinite recursion here, because there 17208b43921e18f314c4fd38049291d323830934c36Chris Lattner // cannot be loops in the value graph that do not go through PHI nodes. 17308b43921e18f314c4fd38049291d323830934c36Chris Lattner unsigned Rank = 0, MaxRank = RankMap[I->getParent()]; 17408b43921e18f314c4fd38049291d323830934c36Chris Lattner for (unsigned i = 0, e = I->getNumOperands(); 17508b43921e18f314c4fd38049291d323830934c36Chris Lattner i != e && Rank != MaxRank; ++i) 17608b43921e18f314c4fd38049291d323830934c36Chris Lattner Rank = std::max(Rank, getRank(I->getOperand(i))); 17700b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 178cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner // If this is a not or neg instruction, do not count it for rank. This 179cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner // assures us that X and ~X will have the same rank. 18042a75517250017a52afb03a0ade03cbd49559fe5Chris Lattner if (!I->getType()->isInteger() || 181fa82b6eba4e1584d7dba291c28fe908272e1e002Owen Anderson (!BinaryOperator::isNot(I) && !BinaryOperator::isNeg(I))) 182cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner ++Rank; 183cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner 184bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner //DEBUG(errs() << "Calculated Rank[" << V->getName() << "] = " 185bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner // << Rank << "\n"); 18600b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 187cc8a2b98f28c10d93f45489b8c6f0c8b8205bb3bChris Lattner return CachedRank = Rank; 1884fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 1894fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 190c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner/// isReassociableOp - Return true if V is an instruction of the specified 191c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner/// opcode and if it only has one use. 192c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattnerstatic BinaryOperator *isReassociableOp(Value *V, unsigned Opcode) { 193e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner if ((V->hasOneUse() || V->use_empty()) && isa<Instruction>(V) && 194c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner cast<Instruction>(V)->getOpcode() == Opcode) 195c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner return cast<BinaryOperator>(V); 196c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner return 0; 197c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner} 1984fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 199f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner/// LowerNegateToMultiply - Replace 0-X with X*-1. 200f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner/// 201f4978e2094a08760d4fa8a07052091cb7276eec7Dale Johannesenstatic Instruction *LowerNegateToMultiply(Instruction *Neg, 202fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson std::map<AssertingVH<>, unsigned> &ValueRankMap, 203e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context) { 204a7235ea7245028a0723e8ab7fd011386b3900777Owen Anderson Constant *Cst = Constant::getAllOnesValue(Neg->getType()); 205f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner 2067cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif Instruction *Res = BinaryOperator::CreateMul(Neg->getOperand(1), Cst, "",Neg); 207f4978e2094a08760d4fa8a07052091cb7276eec7Dale Johannesen ValueRankMap.erase(Neg); 2086934a04a8c15e9971cd1ea4d5c8df2d7afdd5be5Chris Lattner Res->takeName(Neg); 209f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner Neg->replaceAllUsesWith(Res); 210f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner Neg->eraseFromParent(); 211f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner return Res; 212f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner} 213f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner 214c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner// Given an expression of the form '(A+B)+(D+C)', turn it into '(((A+B)+C)+D)'. 215c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner// Note that if D is also part of the expression tree that we recurse to 216c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner// linearize it as well. Besides that case, this does not recurse into A,B, or 217c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner// C. 218c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattnervoid Reassociate::LinearizeExpr(BinaryOperator *I) { 219c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner BinaryOperator *LHS = cast<BinaryOperator>(I->getOperand(0)); 220c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner BinaryOperator *RHS = cast<BinaryOperator>(I->getOperand(1)); 22100b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen assert(isReassociableOp(LHS, I->getOpcode()) && 222c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner isReassociableOp(RHS, I->getOpcode()) && 223c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner "Not an expression that needs linearization?"); 224c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 225bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "Linear" << *LHS << '\n' << *RHS << '\n' << *I << '\n'); 226c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 227c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Move the RHS instruction to live immediately before I, avoiding breaking 228c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // dominator properties. 2294bc5f8071a28b6fc4f4c2207dd03a5f747d0d84bChris Lattner RHS->moveBefore(I); 230c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 231c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Move operands around to do the linearization. 232c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner I->setOperand(1, RHS->getOperand(0)); 233c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner RHS->setOperand(0, LHS); 234c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner I->setOperand(0, RHS); 23500b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 236c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner ++NumLinear; 237c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner MadeChange = true; 238bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "Linearized: " << *I << '\n'); 239fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 240c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // If D is part of this expression tree, tail recurse. 241c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner if (isReassociableOp(I->getOperand(1), I->getOpcode())) 242c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner LinearizeExpr(I); 243c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner} 2444fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 245e4b730441dab4aff9a69aeddbdea98990e7703c4Chris Lattner 246c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner/// LinearizeExprTree - Given an associative binary expression tree, traverse 247c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner/// all of the uses putting it into canonical form. This forces a left-linear 248c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner/// form of the the expression (((a+b)+c)+d), and collects information about the 249c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner/// rank of the non-tree operands. 250c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner/// 251e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// NOTE: These intentionally destroys the expression tree operands (turning 252e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// them into undef values) to reduce #uses of the values. This means that the 253e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// caller MUST use something like RewriteExprTree to put the values back in. 254e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// 255c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattnervoid Reassociate::LinearizeExprTree(BinaryOperator *I, 256c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner std::vector<ValueEntry> &Ops) { 257c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner Value *LHS = I->getOperand(0), *RHS = I->getOperand(1); 258c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner unsigned Opcode = I->getOpcode(); 259e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context = I->getContext(); 260c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 261c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // First step, linearize the expression if it is in ((A+B)+(C+D)) form. 262c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner BinaryOperator *LHSBO = isReassociableOp(LHS, Opcode); 263c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner BinaryOperator *RHSBO = isReassociableOp(RHS, Opcode); 264c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 265f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner // If this is a multiply expression tree and it contains internal negations, 266f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner // transform them into multiplies by -1 so they can be reassociated. 267f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner if (I->getOpcode() == Instruction::Mul) { 268fa82b6eba4e1584d7dba291c28fe908272e1e002Owen Anderson if (!LHSBO && LHS->hasOneUse() && BinaryOperator::isNeg(LHS)) { 269fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson LHS = LowerNegateToMultiply(cast<Instruction>(LHS), 270fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson ValueRankMap, Context); 271f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner LHSBO = isReassociableOp(LHS, Opcode); 272f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner } 273fa82b6eba4e1584d7dba291c28fe908272e1e002Owen Anderson if (!RHSBO && RHS->hasOneUse() && BinaryOperator::isNeg(RHS)) { 274fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson RHS = LowerNegateToMultiply(cast<Instruction>(RHS), 275fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson ValueRankMap, Context); 276f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner RHSBO = isReassociableOp(RHS, Opcode); 277f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner } 278f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner } 279f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner 280c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner if (!LHSBO) { 281c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner if (!RHSBO) { 282c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Neither the LHS or RHS as part of the tree, thus this is a leaf. As 283c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // such, just remember these operands and their rank. 284c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner Ops.push_back(ValueEntry(getRank(LHS), LHS)); 285c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner Ops.push_back(ValueEntry(getRank(RHS), RHS)); 286e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner 287e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // Clear the leaves out. 2889e9a0d5fc26878e51a58a8b57900fcbf952c2691Owen Anderson I->setOperand(0, UndefValue::get(I->getType())); 2899e9a0d5fc26878e51a58a8b57900fcbf952c2691Owen Anderson I->setOperand(1, UndefValue::get(I->getType())); 290c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner return; 291c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } else { 292c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Turn X+(Y+Z) -> (Y+Z)+X 293c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner std::swap(LHSBO, RHSBO); 294c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner std::swap(LHS, RHS); 295c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner bool Success = !I->swapOperands(); 296c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner assert(Success && "swapOperands failed"); 29759500c8f9a76b3386329b6f837255c16f4e8b61bDevang Patel Success = false; 298c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner MadeChange = true; 299c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } 300c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } else if (RHSBO) { 301c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Turn (A+B)+(C+D) -> (((A+B)+C)+D). This guarantees the the RHS is not 302c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // part of the expression tree. 303c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner LinearizeExpr(I); 304c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner LHS = LHSBO = cast<BinaryOperator>(I->getOperand(0)); 305c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner RHS = I->getOperand(1); 306c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner RHSBO = 0; 3074fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner } 308fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman 309c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Okay, now we know that the LHS is a nested expression and that the RHS is 310c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // not. Perform reassociation. 311c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner assert(!isReassociableOp(RHS, Opcode) && "LinearizeExpr failed!"); 3124fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 313c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Move LHS right before I to make sure that the tree expression dominates all 314c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // values. 3154bc5f8071a28b6fc4f4c2207dd03a5f747d0d84bChris Lattner LHSBO->moveBefore(I); 316c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 317c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Linearize the expression tree on the LHS. 318c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner LinearizeExprTree(LHSBO, Ops); 319c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 320c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // Remember the RHS operand and its rank. 321c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner Ops.push_back(ValueEntry(getRank(RHS), RHS)); 322e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner 323e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // Clear the RHS leaf out. 3249e9a0d5fc26878e51a58a8b57900fcbf952c2691Owen Anderson I->setOperand(1, UndefValue::get(I->getType())); 325c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner} 326c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 327c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner// RewriteExprTree - Now that the operands for this expression tree are 328c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner// linearized and optimized, emit them in-order. This function is written to be 329c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner// tail recursive. 330e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattnervoid Reassociate::RewriteExprTree(BinaryOperator *I, 331e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner std::vector<ValueEntry> &Ops, 332e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner unsigned i) { 333c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner if (i+2 == Ops.size()) { 334c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner if (I->getOperand(0) != Ops[i].Op || 335c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner I->getOperand(1) != Ops[i+1].Op) { 336e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *OldLHS = I->getOperand(0); 337bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "RA: " << *I << '\n'); 338c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner I->setOperand(0, Ops[i].Op); 339c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner I->setOperand(1, Ops[i+1].Op); 340bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "TO: " << *I << '\n'); 341c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner MadeChange = true; 342c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner ++NumChanged; 343e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 344e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // If we reassociated a tree to fewer operands (e.g. (1+a+2) -> (a+3) 345e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // delete the extra, now dead, nodes. 346e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner RemoveDeadBinaryOp(OldLHS); 347c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } 348c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner return; 349c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } 350c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner assert(i+2 < Ops.size() && "Ops index out of range!"); 351c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 352c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner if (I->getOperand(1) != Ops[i].Op) { 353bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "RA: " << *I << '\n'); 354c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner I->setOperand(1, Ops[i].Op); 355bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "TO: " << *I << '\n'); 356c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner MadeChange = true; 357c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner ++NumChanged; 358c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner } 359e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 360e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner BinaryOperator *LHS = cast<BinaryOperator>(I->getOperand(0)); 361e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner assert(LHS->getOpcode() == I->getOpcode() && 362e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner "Improper expression tree!"); 363e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 364e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // Compactify the tree instructions together with each other to guarantee 365e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // that the expression tree is dominated by all of Ops. 366e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner LHS->moveBefore(I); 367e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner RewriteExprTree(LHS, Ops, i+1); 3684fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 3694fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 3704fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 371c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 372a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner// NegateValue - Insert instructions before the instruction pointed to by BI, 373a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner// that computes the negative version of the value specified. The negative 374a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner// version of the value is returned, and BI is left pointing at the instruction 375a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner// that should be processed next by the reassociation pass. 376a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner// 377e922c0201916e0b980ab3cfe91e1413e68d55647Owen Andersonstatic Value *NegateValue(LLVMContext &Context, Value *V, Instruction *BI) { 378a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // We are trying to expose opportunity for reassociation. One of the things 379a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // that we want to do to achieve this is to push a negation as deep into an 380a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // expression chain as possible, to expose the add instructions. In practice, 381a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // this means that we turn this: 382a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // X = -(A+12+C+D) into X = -A + -12 + -C + -D = -12 + -A + -C + -D 383a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // so that later, a: Y = 12+X could get reassociated with the -12 to eliminate 384a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // the constants. We assume that instcombine will clean up the mess later if 3855560c9d49ccae132cabf1155f18aa0480dce3edaMisha Brukman // we introduce tons of unnecessary negation instructions... 386a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // 387a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner if (Instruction *I = dyn_cast<Instruction>(V)) 388fd05924946ebfcfb3409b21996cfd0836e4ddb31Chris Lattner if (I->getOpcode() == Instruction::Add && I->hasOneUse()) { 3892cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner // Push the negates through the add. 3900a5372ed3e8cda10d724feda3c1a1c998db05ca0Owen Anderson I->setOperand(0, NegateValue(Context, I->getOperand(0), BI)); 3910a5372ed3e8cda10d724feda3c1a1c998db05ca0Owen Anderson I->setOperand(1, NegateValue(Context, I->getOperand(1), BI)); 3922cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner 3932cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner // We must move the add instruction here, because the neg instructions do 3942cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner // not dominate the old add instruction in general. By moving it, we are 3952cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner // assured that the neg instructions we just inserted dominate the 3962cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner // instruction we are about to insert after them. 397a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // 3982cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner I->moveBefore(BI); 3992cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner I->setName(I->getName()+".neg"); 4002cd85da3ed8e703729fb5adfe8cc2f9b1dd2f6a8Chris Lattner return I; 401a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner } 402a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner 403a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // Insert a 'neg' instruction that subtracts the value from zero to get the 404a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // negation. 405a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner // 4064ae5126d041768ab9665cf2f11c024becd76c41fDan Gohman return BinaryOperator::CreateNeg(V, V->getName() + ".neg", BI); 407a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner} 408a36e6c8cd58c2876decd2d0402064ac349bbec71Chris Lattner 4099bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner/// ShouldBreakUpSubtract - Return true if we should break up this subtract of 4109bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner/// X-Y into (X + -Y). 411e922c0201916e0b980ab3cfe91e1413e68d55647Owen Andersonstatic bool ShouldBreakUpSubtract(LLVMContext &Context, Instruction *Sub) { 4129bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner // If this is a negation, we can't split it up! 413fa82b6eba4e1584d7dba291c28fe908272e1e002Owen Anderson if (BinaryOperator::isNeg(Sub)) 4149bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return false; 4159bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner 4169bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner // Don't bother to break this up unless either the LHS is an associable add or 4170b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner // subtract or if this is only used by one. 4180b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner if (isReassociableOp(Sub->getOperand(0), Instruction::Add) || 4190b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner isReassociableOp(Sub->getOperand(0), Instruction::Sub)) 4209bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return true; 4210b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner if (isReassociableOp(Sub->getOperand(1), Instruction::Add) || 4225329bb22e9b6374d62919981c1ef8775b42945ebChris Lattner isReassociableOp(Sub->getOperand(1), Instruction::Sub)) 4239bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return true; 4240b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner if (Sub->hasOneUse() && 4250b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner (isReassociableOp(Sub->use_back(), Instruction::Add) || 4260b0803ae1508ff514dd7b471a2a3bcd1e83cb0efChris Lattner isReassociableOp(Sub->use_back(), Instruction::Sub))) 4279bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return true; 4289bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner 4299bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner return false; 4309bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner} 4319bc5ed78c860694ccb4ea63c96c2c9212a8b245bChris Lattner 43208b43921e18f314c4fd38049291d323830934c36Chris Lattner/// BreakUpSubtract - If we have (X-Y), and if either X is an add, or if this is 43308b43921e18f314c4fd38049291d323830934c36Chris Lattner/// only used by an add, transform this into (X+(0-Y)) to promote better 43408b43921e18f314c4fd38049291d323830934c36Chris Lattner/// reassociation. 435e922c0201916e0b980ab3cfe91e1413e68d55647Owen Andersonstatic Instruction *BreakUpSubtract(LLVMContext &Context, Instruction *Sub, 436d3c7b7359d4992b9ab9f8e12ccd0a9b7d2446566Chris Lattner std::map<AssertingVH<>, unsigned> &ValueRankMap) { 43708b43921e18f314c4fd38049291d323830934c36Chris Lattner // Convert a subtract into an add and a neg instruction... so that sub 43808b43921e18f314c4fd38049291d323830934c36Chris Lattner // instructions can be commuted with other add instructions... 43908b43921e18f314c4fd38049291d323830934c36Chris Lattner // 44008b43921e18f314c4fd38049291d323830934c36Chris Lattner // Calculate the negative value of Operand 1 of the sub instruction... 44108b43921e18f314c4fd38049291d323830934c36Chris Lattner // and set it as the RHS of the add instruction we just made... 44208b43921e18f314c4fd38049291d323830934c36Chris Lattner // 4430a5372ed3e8cda10d724feda3c1a1c998db05ca0Owen Anderson Value *NegVal = NegateValue(Context, Sub->getOperand(1), Sub); 44408b43921e18f314c4fd38049291d323830934c36Chris Lattner Instruction *New = 4457cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif BinaryOperator::CreateAdd(Sub->getOperand(0), NegVal, "", Sub); 4466934a04a8c15e9971cd1ea4d5c8df2d7afdd5be5Chris Lattner New->takeName(Sub); 44708b43921e18f314c4fd38049291d323830934c36Chris Lattner 44808b43921e18f314c4fd38049291d323830934c36Chris Lattner // Everyone now refers to the add instruction. 449f4978e2094a08760d4fa8a07052091cb7276eec7Dale Johannesen ValueRankMap.erase(Sub); 45008b43921e18f314c4fd38049291d323830934c36Chris Lattner Sub->replaceAllUsesWith(New); 45108b43921e18f314c4fd38049291d323830934c36Chris Lattner Sub->eraseFromParent(); 45200b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 453bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "Negated: " << *New << '\n'); 45408b43921e18f314c4fd38049291d323830934c36Chris Lattner return New; 45508b43921e18f314c4fd38049291d323830934c36Chris Lattner} 45608b43921e18f314c4fd38049291d323830934c36Chris Lattner 4570975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner/// ConvertShiftToMul - If this is a shift of a reassociable multiply or is used 4580975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner/// by one, change this into a multiply by a constant to assist with further 4590975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner/// reassociation. 460f4978e2094a08760d4fa8a07052091cb7276eec7Dale Johannesenstatic Instruction *ConvertShiftToMul(Instruction *Shl, 461fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson std::map<AssertingVH<>, unsigned> &ValueRankMap, 462e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context) { 46322a66c41f3ab42c15437033851395b0b8288681bChris Lattner // If an operand of this shift is a reassociable multiply, or if the shift 46422a66c41f3ab42c15437033851395b0b8288681bChris Lattner // is used by a reassociable multiply or add, turn into a multiply. 46522a66c41f3ab42c15437033851395b0b8288681bChris Lattner if (isReassociableOp(Shl->getOperand(0), Instruction::Mul) || 46622a66c41f3ab42c15437033851395b0b8288681bChris Lattner (Shl->hasOneUse() && 46722a66c41f3ab42c15437033851395b0b8288681bChris Lattner (isReassociableOp(Shl->use_back(), Instruction::Mul) || 46822a66c41f3ab42c15437033851395b0b8288681bChris Lattner isReassociableOp(Shl->use_back(), Instruction::Add)))) { 469eed707b1e6097aac2bb6b3d47271f6300ace7f2eOwen Anderson Constant *MulCst = ConstantInt::get(Shl->getType(), 1); 470fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson MulCst = 471baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson ConstantExpr::getShl(MulCst, cast<Constant>(Shl->getOperand(1))); 47222a66c41f3ab42c15437033851395b0b8288681bChris Lattner 4737cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif Instruction *Mul = BinaryOperator::CreateMul(Shl->getOperand(0), MulCst, 4746934a04a8c15e9971cd1ea4d5c8df2d7afdd5be5Chris Lattner "", Shl); 475f4978e2094a08760d4fa8a07052091cb7276eec7Dale Johannesen ValueRankMap.erase(Shl); 4766934a04a8c15e9971cd1ea4d5c8df2d7afdd5be5Chris Lattner Mul->takeName(Shl); 47722a66c41f3ab42c15437033851395b0b8288681bChris Lattner Shl->replaceAllUsesWith(Mul); 47822a66c41f3ab42c15437033851395b0b8288681bChris Lattner Shl->eraseFromParent(); 47922a66c41f3ab42c15437033851395b0b8288681bChris Lattner return Mul; 48022a66c41f3ab42c15437033851395b0b8288681bChris Lattner } 48122a66c41f3ab42c15437033851395b0b8288681bChris Lattner return 0; 4820975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner} 4830975ed5f4ef7264b45995241717055f8a116bb27Chris Lattner 484109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner// Scan backwards and forwards among values with the same rank as element i to 485109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner// see if X exists. If X does not exist, return i. 486109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattnerstatic unsigned FindInOperandList(std::vector<ValueEntry> &Ops, unsigned i, 487109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner Value *X) { 488109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner unsigned XRank = Ops[i].Rank; 489109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner unsigned e = Ops.size(); 490109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner for (unsigned j = i+1; j != e && Ops[j].Rank == XRank; ++j) 491109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (Ops[j].Op == X) 492109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner return j; 493109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // Scan backwards 494109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner for (unsigned j = i-1; j != ~0U && Ops[j].Rank == XRank; --j) 495109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (Ops[j].Op == X) 496109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner return j; 497109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner return i; 498109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner} 499109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner 500e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// EmitAddTreeOfValues - Emit a tree of add instructions, summing Ops together 501e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// and returning the result. Insert the tree before I. 502e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattnerstatic Value *EmitAddTreeOfValues(Instruction *I, std::vector<Value*> &Ops) { 503e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (Ops.size() == 1) return Ops.back(); 504e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 505e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *V1 = Ops.back(); 506e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Ops.pop_back(); 507e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *V2 = EmitAddTreeOfValues(I, Ops); 5087cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif return BinaryOperator::CreateAdd(V2, V1, "tmp", I); 509e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 510e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 511e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// RemoveFactorFromExpression - If V is an expression tree that is a 512e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// multiplication sequence, and if this sequence contains a multiply by Factor, 513e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner/// remove Factor from the tree and return the new tree. 514e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris LattnerValue *Reassociate::RemoveFactorFromExpression(Value *V, Value *Factor) { 515e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner BinaryOperator *BO = isReassociableOp(V, Instruction::Mul); 516e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (!BO) return 0; 517e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 518e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner std::vector<ValueEntry> Factors; 519e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner LinearizeExprTree(BO, Factors); 520e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 521e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner bool FoundFactor = false; 522e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner for (unsigned i = 0, e = Factors.size(); i != e; ++i) 523e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (Factors[i].Op == Factor) { 524e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner FoundFactor = true; 525e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Factors.erase(Factors.begin()+i); 526e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner break; 527e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 528e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner if (!FoundFactor) { 529e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // Make sure to restore the operands to the expression tree. 530e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner RewriteExprTree(BO, Factors); 531e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner return 0; 532e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner } 533e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 534e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (Factors.size() == 1) return Factors[0].Op; 535e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 536e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner RewriteExprTree(BO, Factors); 537e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return BO; 538e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner} 539e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 540e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// FindSingleUseMultiplyFactors - If V is a single-use multiply, recursively 541e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner/// add its operands as factors, otherwise add V to the list of factors. 542e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattnerstatic void FindSingleUseMultiplyFactors(Value *V, 543e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner std::vector<Value*> &Factors) { 544e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner BinaryOperator *BO; 545e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner if ((!V->hasOneUse() && !V->use_empty()) || 546e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner !(BO = dyn_cast<BinaryOperator>(V)) || 547e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner BO->getOpcode() != Instruction::Mul) { 548e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner Factors.push_back(V); 549e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner return; 550e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner } 551e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner 552e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // Otherwise, add the LHS and RHS to the list of factors. 553e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner FindSingleUseMultiplyFactors(BO->getOperand(1), Factors); 554e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner FindSingleUseMultiplyFactors(BO->getOperand(0), Factors); 555e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner} 556e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner 557e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner 558e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 559e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris LattnerValue *Reassociate::OptimizeExpression(BinaryOperator *I, 560e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner std::vector<ValueEntry> &Ops) { 561469001000620df176decd093a300db84a06cc78bChris Lattner // Now that we have the linearized expression tree, try to optimize it. 562469001000620df176decd093a300db84a06cc78bChris Lattner // Start by folding any constants that we found. 563109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner bool IterateOptimization = false; 564e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (Ops.size() == 1) return Ops[0].Op; 565469001000620df176decd093a300db84a06cc78bChris Lattner 566e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner unsigned Opcode = I->getOpcode(); 567e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 568469001000620df176decd093a300db84a06cc78bChris Lattner if (Constant *V1 = dyn_cast<Constant>(Ops[Ops.size()-2].Op)) 569469001000620df176decd093a300db84a06cc78bChris Lattner if (Constant *V2 = dyn_cast<Constant>(Ops.back().Op)) { 570469001000620df176decd093a300db84a06cc78bChris Lattner Ops.pop_back(); 571baf3c404409d5e47b13984a7f95bfbd6d1f2e79eOwen Anderson Ops.back().Op = ConstantExpr::get(Opcode, V1, V2); 572e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return OptimizeExpression(I, Ops); 573469001000620df176decd093a300db84a06cc78bChris Lattner } 574469001000620df176decd093a300db84a06cc78bChris Lattner 575469001000620df176decd093a300db84a06cc78bChris Lattner // Check for destructive annihilation due to a constant being used. 5766b6b6ef1677fa71b1072c2911b4c1f9524a558c9Zhou Sheng if (ConstantInt *CstVal = dyn_cast<ConstantInt>(Ops.back().Op)) 577469001000620df176decd093a300db84a06cc78bChris Lattner switch (Opcode) { 578469001000620df176decd093a300db84a06cc78bChris Lattner default: break; 579469001000620df176decd093a300db84a06cc78bChris Lattner case Instruction::And: 580cae5754619433aed7be74abbf1c0551a82d369cbReid Spencer if (CstVal->isZero()) { // ... & 0 -> 0 581109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 582e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return CstVal; 583469001000620df176decd093a300db84a06cc78bChris Lattner } else if (CstVal->isAllOnesValue()) { // ... & -1 -> ... 584469001000620df176decd093a300db84a06cc78bChris Lattner Ops.pop_back(); 585469001000620df176decd093a300db84a06cc78bChris Lattner } 586469001000620df176decd093a300db84a06cc78bChris Lattner break; 587469001000620df176decd093a300db84a06cc78bChris Lattner case Instruction::Mul: 588cae5754619433aed7be74abbf1c0551a82d369cbReid Spencer if (CstVal->isZero()) { // ... * 0 -> 0 589109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 590e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return CstVal; 591cae5754619433aed7be74abbf1c0551a82d369cbReid Spencer } else if (cast<ConstantInt>(CstVal)->isOne()) { 592469001000620df176decd093a300db84a06cc78bChris Lattner Ops.pop_back(); // ... * 1 -> ... 593469001000620df176decd093a300db84a06cc78bChris Lattner } 594469001000620df176decd093a300db84a06cc78bChris Lattner break; 595469001000620df176decd093a300db84a06cc78bChris Lattner case Instruction::Or: 596469001000620df176decd093a300db84a06cc78bChris Lattner if (CstVal->isAllOnesValue()) { // ... | -1 -> -1 597109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 598e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return CstVal; 599469001000620df176decd093a300db84a06cc78bChris Lattner } 600469001000620df176decd093a300db84a06cc78bChris Lattner // FALLTHROUGH! 601469001000620df176decd093a300db84a06cc78bChris Lattner case Instruction::Add: 602469001000620df176decd093a300db84a06cc78bChris Lattner case Instruction::Xor: 603cae5754619433aed7be74abbf1c0551a82d369cbReid Spencer if (CstVal->isZero()) // ... [|^+] 0 -> ... 604469001000620df176decd093a300db84a06cc78bChris Lattner Ops.pop_back(); 605469001000620df176decd093a300db84a06cc78bChris Lattner break; 606469001000620df176decd093a300db84a06cc78bChris Lattner } 607e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (Ops.size() == 1) return Ops[0].Op; 608469001000620df176decd093a300db84a06cc78bChris Lattner 609469001000620df176decd093a300db84a06cc78bChris Lattner // Handle destructive annihilation do to identities between elements in the 610469001000620df176decd093a300db84a06cc78bChris Lattner // argument list here. 611109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner switch (Opcode) { 612109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner default: break; 613109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner case Instruction::And: 614109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner case Instruction::Or: 615109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner case Instruction::Xor: 616109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // Scan the operand lists looking for X and ~X pairs, along with X,X pairs. 617109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // If we find any, we can simplify the expression. X&~X == 0, X|~X == -1. 618109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 619109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // First, check for X and ~X in the operand list. 620368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner assert(i < Ops.size()); 621109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (BinaryOperator::isNot(Ops[i].Op)) { // Cannot occur for ^. 622109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner Value *X = BinaryOperator::getNotArgument(Ops[i].Op); 623109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner unsigned FoundX = FindInOperandList(Ops, i, X); 624109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (FoundX != i) { 625109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (Opcode == Instruction::And) { // ...&X&~X = 0 626109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 627a7235ea7245028a0723e8ab7fd011386b3900777Owen Anderson return Constant::getNullValue(X->getType()); 628109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } else if (Opcode == Instruction::Or) { // ...|X|~X = -1 629109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 630a7235ea7245028a0723e8ab7fd011386b3900777Owen Anderson return Constant::getAllOnesValue(X->getType()); 631109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 632109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 633109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 634109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner 635109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // Next, check for duplicate pairs of values, which we assume are next to 636109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // each other, due to our sorting criteria. 637368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner assert(i < Ops.size()); 638109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (i+1 != Ops.size() && Ops[i+1].Op == Ops[i].Op) { 639109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (Opcode == Instruction::And || Opcode == Instruction::Or) { 640109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // Drop duplicate values. 641109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner Ops.erase(Ops.begin()+i); 642109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner --i; --e; 643109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner IterateOptimization = true; 644109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 645109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } else { 646109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner assert(Opcode == Instruction::Xor); 647ac83b0301ea5ce0e1092fad8f294fe7f046832ffChris Lattner if (e == 2) { 648ac83b0301ea5ce0e1092fad8f294fe7f046832ffChris Lattner ++NumAnnihil; 649a7235ea7245028a0723e8ab7fd011386b3900777Owen Anderson return Constant::getNullValue(Ops[0].Op->getType()); 650ac83b0301ea5ce0e1092fad8f294fe7f046832ffChris Lattner } 651109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // ... X^X -> ... 652109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner Ops.erase(Ops.begin()+i, Ops.begin()+i+2); 653ac83b0301ea5ce0e1092fad8f294fe7f046832ffChris Lattner i -= 1; e -= 2; 654109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner IterateOptimization = true; 655109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 656109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 657109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 658109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 659109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner break; 660109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner 661109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner case Instruction::Add: 662109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // Scan the operand lists looking for X and -X pairs. If we find any, we 663e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // can simplify the expression. X+-X == 0. 664109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 665368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner assert(i < Ops.size()); 666109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // Check for X and -X in the operand list. 667fa82b6eba4e1584d7dba291c28fe908272e1e002Owen Anderson if (BinaryOperator::isNeg(Ops[i].Op)) { 668109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner Value *X = BinaryOperator::getNegArgument(Ops[i].Op); 669109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner unsigned FoundX = FindInOperandList(Ops, i, X); 670109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (FoundX != i) { 671109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner // Remove X and -X from the operand list. 672109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner if (Ops.size() == 2) { 673109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 674a7235ea7245028a0723e8ab7fd011386b3900777Owen Anderson return Constant::getNullValue(X->getType()); 675109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } else { 676109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner Ops.erase(Ops.begin()+i); 677368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner if (i < FoundX) 678368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner --FoundX; 679368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner else 680368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner --i; // Need to back up an extra one. 681109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner Ops.erase(Ops.begin()+FoundX); 682109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner IterateOptimization = true; 683109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner ++NumAnnihil; 684368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner --i; // Revisit element. 685368a3aabb2b48ad6e39d23d1c6cbdfe0c5857483Chris Lattner e -= 2; // Removed two elements. 686109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 687109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 688109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 689109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 690e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 691e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 692e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // Scan the operand list, checking to see if there are any common factors 693e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // between operands. Consider something like A*A+A*B*C+D. We would like to 694e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // reassociate this to A*(A+B*C)+D, which reduces the number of multiplies. 695e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // To efficiently find this, we count the number of times a factor occurs 696e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // for any ADD operands that are MULs. 697e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner std::map<Value*, unsigned> FactorOccurrences; 698e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner unsigned MaxOcc = 0; 699e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *MaxOccVal = 0; 70024d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 70124d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(Ops[i].Op)) { 70224d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer if (BOp->getOpcode() == Instruction::Mul && BOp->use_empty()) { 70324d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer // Compute all of the factors of this added value. 70424d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer std::vector<Value*> Factors; 70524d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer FindSingleUseMultiplyFactors(BOp, Factors); 70624d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer assert(Factors.size() > 1 && "Bad linearize!"); 70724d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer 70824d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer // Add one to FactorOccurrences for each unique factor in this op. 70924d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer if (Factors.size() == 2) { 71024d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer unsigned Occ = ++FactorOccurrences[Factors[0]]; 71124d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer if (Occ > MaxOcc) { MaxOcc = Occ; MaxOccVal = Factors[0]; } 71224d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer if (Factors[0] != Factors[1]) { // Don't double count A*A. 71324d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer Occ = ++FactorOccurrences[Factors[1]]; 71424d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer if (Occ > MaxOcc) { MaxOcc = Occ; MaxOccVal = Factors[1]; } 71524d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer } 71624d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer } else { 71724d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer std::set<Value*> Duplicates; 71824d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer for (unsigned i = 0, e = Factors.size(); i != e; ++i) { 71924d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer if (Duplicates.insert(Factors[i]).second) { 72024d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer unsigned Occ = ++FactorOccurrences[Factors[i]]; 72124d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer if (Occ > MaxOcc) { MaxOcc = Occ; MaxOccVal = Factors[i]; } 722e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 723e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 724e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 72524d6da5fedcf39891f7d8c5b031c01324b3db545Reid Spencer } 726e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 727e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 728e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 729e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // If any factor occurred more than one time, we can pull it out. 730e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (MaxOcc > 1) { 731bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "\nFACTORING [" << MaxOcc << "]: " << *MaxOccVal << "\n"); 732e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 733e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // Create a new instruction that uses the MaxOccVal twice. If we don't do 734e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // this, we could otherwise run into situations where removing a factor 735e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // from an expression will drop a use of maxocc, and this can cause 736e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // RemoveFactorFromExpression on successive values to behave differently. 7377cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif Instruction *DummyInst = BinaryOperator::CreateAdd(MaxOccVal, MaxOccVal); 738e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner std::vector<Value*> NewMulOps; 739e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner for (unsigned i = 0, e = Ops.size(); i != e; ++i) { 740e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner if (Value *V = RemoveFactorFromExpression(Ops[i].Op, MaxOccVal)) { 741e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner NewMulOps.push_back(V); 742e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Ops.erase(Ops.begin()+i); 743e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner --i; --e; 744e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 745e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 746e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 747e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // No need for extra uses anymore. 748e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner delete DummyInst; 749e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 750e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner unsigned NumAddedValues = NewMulOps.size(); 751e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Value *V = EmitAddTreeOfValues(I, NewMulOps); 7527cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif Value *V2 = BinaryOperator::CreateMul(V, MaxOccVal, "tmp", I); 753e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 754e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // Now that we have inserted V and its sole use, optimize it. This allows 755e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // us to handle cases that require multiple factoring steps, such as this: 756e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner // A*A*B + A*A*C --> A*(A*B+A*C) --> A*(A*(B+C)) 757e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner if (NumAddedValues > 1) 758e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner ReassociateExpression(cast<BinaryOperator>(V)); 759e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner 760e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner ++NumFactor; 761e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 762303595942502f17c087fa28874c2b89117148c45Dan Gohman if (Ops.empty()) 763e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner return V2; 764e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 765e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // Add the new value to the list of things being added. 766e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner Ops.insert(Ops.begin(), ValueEntry(getRank(V2), V2)); 767e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner 768e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner // Rewrite the tree so that there is now a use of V. 769e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner RewriteExprTree(I, Ops); 770e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return OptimizeExpression(I, Ops); 771e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner } 772109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner break; 773109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner //case Instruction::Mul: 774109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner } 775109d34d6ff51a0fdd39d7b3b373a83fcca6c67a3Chris Lattner 77600b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen if (IterateOptimization) 777e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return OptimizeExpression(I, Ops); 778e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner return 0; 779469001000620df176decd093a300db84a06cc78bChris Lattner} 780469001000620df176decd093a300db84a06cc78bChris Lattner 78108b43921e18f314c4fd38049291d323830934c36Chris Lattner 78208b43921e18f314c4fd38049291d323830934c36Chris Lattner/// ReassociateBB - Inspect all of the instructions in this basic block, 78308b43921e18f314c4fd38049291d323830934c36Chris Lattner/// reassociating them as we go. 784c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattnervoid Reassociate::ReassociateBB(BasicBlock *BB) { 785e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &Context = BB->getContext(); 786e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson 787e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner for (BasicBlock::iterator BBI = BB->begin(); BBI != BB->end(); ) { 788e5022fe4cd83eef91f5c3a21c943ca9b65507ab8Chris Lattner Instruction *BI = BBI++; 789641f02f10f08c9a9add651c6f0169f5441eaeb49Chris Lattner if (BI->getOpcode() == Instruction::Shl && 790641f02f10f08c9a9add651c6f0169f5441eaeb49Chris Lattner isa<ConstantInt>(BI->getOperand(1))) 791fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson if (Instruction *NI = ConvertShiftToMul(BI, ValueRankMap, Context)) { 792641f02f10f08c9a9add651c6f0169f5441eaeb49Chris Lattner MadeChange = true; 793641f02f10f08c9a9add651c6f0169f5441eaeb49Chris Lattner BI = NI; 794641f02f10f08c9a9add651c6f0169f5441eaeb49Chris Lattner } 795641f02f10f08c9a9add651c6f0169f5441eaeb49Chris Lattner 7966f156856ca23394122f39d92fe74eec40a1f7c27Chris Lattner // Reject cases where it is pointless to do this. 797e4d87aa2de6e52952dca73716386db09aad5a8fdReid Spencer if (!isa<BinaryOperator>(BI) || BI->getType()->isFloatingPoint() || 7989d6565a5b1fbc4286d6ee638d8f47a3171a9ed7eReid Spencer isa<VectorType>(BI->getType())) 7996f156856ca23394122f39d92fe74eec40a1f7c27Chris Lattner continue; // Floating point ops are not associative. 8006f156856ca23394122f39d92fe74eec40a1f7c27Chris Lattner 80108b43921e18f314c4fd38049291d323830934c36Chris Lattner // If this is a subtract instruction which is not already in negate form, 80208b43921e18f314c4fd38049291d323830934c36Chris Lattner // see if we can convert it to X+-Y. 803f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner if (BI->getOpcode() == Instruction::Sub) { 8040a5372ed3e8cda10d724feda3c1a1c998db05ca0Owen Anderson if (ShouldBreakUpSubtract(Context, BI)) { 8050a5372ed3e8cda10d724feda3c1a1c998db05ca0Owen Anderson BI = BreakUpSubtract(Context, BI, ValueRankMap); 806d5b8d92b9f4dfb216e4f2a52b4e801d7559574baChris Lattner MadeChange = true; 807fa82b6eba4e1584d7dba291c28fe908272e1e002Owen Anderson } else if (BinaryOperator::isNeg(BI)) { 808f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner // Otherwise, this is a negation. See if the operand is a multiply tree 809f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner // and if this is not an inner node of a multiply tree. 810f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner if (isReassociableOp(BI->getOperand(1), Instruction::Mul) && 811f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner (!BI->hasOneUse() || 812f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner !isReassociableOp(BI->use_back(), Instruction::Mul))) { 813fa5cbd6d0fbda23fd669c8718e07b19001b2d21aOwen Anderson BI = LowerNegateToMultiply(BI, ValueRankMap, Context); 814f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner MadeChange = true; 815f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner } 81608b43921e18f314c4fd38049291d323830934c36Chris Lattner } 817f33151aff008c40eec6435ddb7a5c9017b6acef9Chris Lattner } 818e4b730441dab4aff9a69aeddbdea98990e7703c4Chris Lattner 819c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // If this instruction is a commutative binary operator, process it. 820c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner if (!BI->isAssociative()) continue; 821c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner BinaryOperator *I = cast<BinaryOperator>(BI); 82200b16889ab461b7ecef1c91ade101186b7f1fce2Jeff Cohen 823c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // If this is an interior node of a reassociable tree, ignore it until we 824c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner // get to the root of the tree, to avoid N^2 analysis. 825c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner if (I->hasOneUse() && isReassociableOp(I->use_back(), I->getOpcode())) 826c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner continue; 827c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner 8287b4ad94282b94e1827be29b4db73fdf6e241f748Chris Lattner // If this is an add tree that is used by a sub instruction, ignore it 8297b4ad94282b94e1827be29b4db73fdf6e241f748Chris Lattner // until we process the subtract. 8307b4ad94282b94e1827be29b4db73fdf6e241f748Chris Lattner if (I->hasOneUse() && I->getOpcode() == Instruction::Add && 8317b4ad94282b94e1827be29b4db73fdf6e241f748Chris Lattner cast<Instruction>(I->use_back())->getOpcode() == Instruction::Sub) 8327b4ad94282b94e1827be29b4db73fdf6e241f748Chris Lattner continue; 8337b4ad94282b94e1827be29b4db73fdf6e241f748Chris Lattner 834895b392269cad07c34d59110d68dc86708c53adbChris Lattner ReassociateExpression(I); 835895b392269cad07c34d59110d68dc86708c53adbChris Lattner } 836895b392269cad07c34d59110d68dc86708c53adbChris Lattner} 837c9fd097a01383323f166c14c17d3984620cad766Chris Lattner 838895b392269cad07c34d59110d68dc86708c53adbChris Lattnervoid Reassociate::ReassociateExpression(BinaryOperator *I) { 839895b392269cad07c34d59110d68dc86708c53adbChris Lattner 840895b392269cad07c34d59110d68dc86708c53adbChris Lattner // First, walk the expression tree, linearizing the tree, collecting 841895b392269cad07c34d59110d68dc86708c53adbChris Lattner std::vector<ValueEntry> Ops; 842895b392269cad07c34d59110d68dc86708c53adbChris Lattner LinearizeExprTree(I, Ops); 843895b392269cad07c34d59110d68dc86708c53adbChris Lattner 844bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "RAIn:\t"; PrintOps(I, Ops); errs() << "\n"); 845895b392269cad07c34d59110d68dc86708c53adbChris Lattner 846895b392269cad07c34d59110d68dc86708c53adbChris Lattner // Now that we have linearized the tree to a list and have gathered all of 847895b392269cad07c34d59110d68dc86708c53adbChris Lattner // the operands and their ranks, sort the operands by their rank. Use a 848895b392269cad07c34d59110d68dc86708c53adbChris Lattner // stable_sort so that values with equal ranks will have their relative 849895b392269cad07c34d59110d68dc86708c53adbChris Lattner // positions maintained (and so the compiler is deterministic). Note that 850895b392269cad07c34d59110d68dc86708c53adbChris Lattner // this sorts so that the highest ranking values end up at the beginning of 851895b392269cad07c34d59110d68dc86708c53adbChris Lattner // the vector. 852895b392269cad07c34d59110d68dc86708c53adbChris Lattner std::stable_sort(Ops.begin(), Ops.end()); 853895b392269cad07c34d59110d68dc86708c53adbChris Lattner 854895b392269cad07c34d59110d68dc86708c53adbChris Lattner // OptimizeExpression - Now that we have the expression tree in a convenient 855895b392269cad07c34d59110d68dc86708c53adbChris Lattner // sorted form, optimize it globally if possible. 856895b392269cad07c34d59110d68dc86708c53adbChris Lattner if (Value *V = OptimizeExpression(I, Ops)) { 857895b392269cad07c34d59110d68dc86708c53adbChris Lattner // This expression tree simplified to something that isn't a tree, 858895b392269cad07c34d59110d68dc86708c53adbChris Lattner // eliminate it. 859bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "Reassoc to scalar: " << *V << "\n"); 860895b392269cad07c34d59110d68dc86708c53adbChris Lattner I->replaceAllUsesWith(V); 861895b392269cad07c34d59110d68dc86708c53adbChris Lattner RemoveDeadBinaryOp(I); 862895b392269cad07c34d59110d68dc86708c53adbChris Lattner return; 863895b392269cad07c34d59110d68dc86708c53adbChris Lattner } 864895b392269cad07c34d59110d68dc86708c53adbChris Lattner 865895b392269cad07c34d59110d68dc86708c53adbChris Lattner // We want to sink immediates as deeply as possible except in the case where 866895b392269cad07c34d59110d68dc86708c53adbChris Lattner // this is a multiply tree used only by an add, and the immediate is a -1. 867895b392269cad07c34d59110d68dc86708c53adbChris Lattner // In this case we reassociate to put the negation on the outside so that we 868895b392269cad07c34d59110d68dc86708c53adbChris Lattner // can fold the negation into the add: (-X)*Y + Z -> Z-X*Y 869895b392269cad07c34d59110d68dc86708c53adbChris Lattner if (I->getOpcode() == Instruction::Mul && I->hasOneUse() && 870895b392269cad07c34d59110d68dc86708c53adbChris Lattner cast<Instruction>(I->use_back())->getOpcode() == Instruction::Add && 871895b392269cad07c34d59110d68dc86708c53adbChris Lattner isa<ConstantInt>(Ops.back().Op) && 872895b392269cad07c34d59110d68dc86708c53adbChris Lattner cast<ConstantInt>(Ops.back().Op)->isAllOnesValue()) { 873895b392269cad07c34d59110d68dc86708c53adbChris Lattner Ops.insert(Ops.begin(), Ops.back()); 874895b392269cad07c34d59110d68dc86708c53adbChris Lattner Ops.pop_back(); 875895b392269cad07c34d59110d68dc86708c53adbChris Lattner } 876895b392269cad07c34d59110d68dc86708c53adbChris Lattner 877bdff548e4dd577a72094d57b282de4e765643b96Chris Lattner DEBUG(errs() << "RAOut:\t"; PrintOps(I, Ops); errs() << "\n"); 878895b392269cad07c34d59110d68dc86708c53adbChris Lattner 879895b392269cad07c34d59110d68dc86708c53adbChris Lattner if (Ops.size() == 1) { 880895b392269cad07c34d59110d68dc86708c53adbChris Lattner // This expression tree simplified to something that isn't a tree, 881895b392269cad07c34d59110d68dc86708c53adbChris Lattner // eliminate it. 882895b392269cad07c34d59110d68dc86708c53adbChris Lattner I->replaceAllUsesWith(Ops[0].Op); 883895b392269cad07c34d59110d68dc86708c53adbChris Lattner RemoveDeadBinaryOp(I); 884895b392269cad07c34d59110d68dc86708c53adbChris Lattner } else { 885895b392269cad07c34d59110d68dc86708c53adbChris Lattner // Now that we ordered and optimized the expressions, splat them back into 886895b392269cad07c34d59110d68dc86708c53adbChris Lattner // the expression tree, removing any unneeded nodes. 887e9efecbf470100696355f32ea8b6ab942183ac6cChris Lattner RewriteExprTree(I, Ops); 8884fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner } 8894fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 8904fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 8914fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 8927e70829632f82de15db187845666aaca6e04b792Chris Lattnerbool Reassociate::runOnFunction(Function &F) { 8934fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner // Recalculate the rank map for F 8944fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner BuildRankMap(F); 8954fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 896c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner MadeChange = false; 8977e70829632f82de15db187845666aaca6e04b792Chris Lattner for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) 898c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner ReassociateBB(FI); 8994fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner 9004fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner // We are done with the rank map... 9014fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner RankMap.clear(); 902fb5be090f59997deb7a2e89c92bac19528ba6755Chris Lattner ValueRankMap.clear(); 903c0649ac931d22b7118c1db292b887cd4eb52cd32Chris Lattner return MadeChange; 9044fd56003ab29e3662c909bb10e47daa97ceb55abChris Lattner} 905d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 906