GVN.cpp revision ea3eec9f8588a1fe0fe80324d1413ab165b675ca
15ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka//===- GVN.cpp - Eliminate redundant values and loads ---------------------===// 25ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// 35ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// The LLVM Compiler Infrastructure 45ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// 55ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// This file is distributed under the University of Illinois Open Source 65ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// License. See LICENSE.TXT for details. 75ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// 85ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka//===----------------------------------------------------------------------===// 95ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// 105ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// This pass performs global value numbering to eliminate fully redundant 115ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// instructions. It also performs simple dead load elimination. 125ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// 135ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// Note that this pass does the value numbering itself; it does not use the 1436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines// ValueNumbering analysis passes. 155ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// 1646090914b783b632618268f2a5c99aab83732688Reed Kotler//===----------------------------------------------------------------------===// 1736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines 185ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#define DEBUG_TYPE "gvn" 195ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/Transforms/Scalar.h" 205ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/BasicBlock.h" 2136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines#include "llvm/Constants.h" 225ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/DerivedTypes.h" 235ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/GlobalVariable.h" 245ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/Function.h" 25dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines#include "llvm/IntrinsicInst.h" 26dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines#include "llvm/LLVMContext.h" 275ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/Operator.h" 285ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/Value.h" 295ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/ADT/DenseMap.h" 305ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/ADT/DepthFirstIterator.h" 315ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/ADT/PostOrderIterator.h" 325ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/ADT/SmallPtrSet.h" 335ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/ADT/SmallVector.h" 345ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka#include "llvm/ADT/Statistic.h" 3590cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer#include "llvm/Analysis/AliasAnalysis.h" 3690cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer#include "llvm/Analysis/ConstantFolding.h" 3790cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer#include "llvm/Analysis/Dominators.h" 3890cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer#include "llvm/Analysis/MemoryBuiltins.h" 3990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer#include "llvm/Analysis/MemoryDependenceAnalysis.h" 4090cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer#include "llvm/Analysis/PHITransAddr.h" 4190cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer#include "llvm/Support/CFG.h" 4290cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer#include "llvm/Support/CommandLine.h" 43b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Support/Debug.h" 44b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Support/ErrorHandling.h" 45b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Support/GetElementPtrTypeIterator.h" 46b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Support/IRBuilder.h" 47b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Support/raw_ostream.h" 48b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Target/TargetData.h" 49b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Transforms/Utils/BasicBlockUtils.h" 50b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Transforms/Utils/Local.h" 51b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler#include "llvm/Transforms/Utils/SSAUpdater.h" 52b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotlerusing namespace llvm; 53b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler 54b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed KotlerSTATISTIC(NumGVNInstr, "Number of instructions deleted"); 555ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaSTATISTIC(NumGVNLoad, "Number of loads deleted"); 565ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaSTATISTIC(NumGVNPRE, "Number of instructions PRE'd"); 5790cd06e90be1db06bc4812ae9ec96b6638847285Benjamin KramerSTATISTIC(NumGVNBlocks, "Number of blocks merged"); 5890cd06e90be1db06bc4812ae9ec96b6638847285Benjamin KramerSTATISTIC(NumPRELoad, "Number of loads PRE'd"); 5990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer 6090cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramerstatic cl::opt<bool> EnablePRE("enable-pre", 6190cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer cl::init(true), cl::Hidden); 6290cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramerstatic cl::opt<bool> EnableLoadPRE("enable-load-pre", cl::init(true)); 6390cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramerstatic cl::opt<bool> EnableFullLoadPRE("enable-full-load-pre", cl::init(false)); 6490cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer 6590cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer//===----------------------------------------------------------------------===// 6690cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer// ValueTable Class 6790cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer//===----------------------------------------------------------------------===// 6890cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer 6990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer/// This class holds the mapping between values and value numbers. It is used 7090cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer/// as an efficient mechanism to determine the expression-wise equivalence of 7190cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer/// two values. 7290cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramernamespace { 7390cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer struct Expression { 7490cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer enum ExpressionOpcode { 7590cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer ADD = Instruction::Add, 7690cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer FADD = Instruction::FAdd, 7790cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer SUB = Instruction::Sub, 7890cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer FSUB = Instruction::FSub, 7990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer MUL = Instruction::Mul, 8090cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer FMUL = Instruction::FMul, 8190cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer UDIV = Instruction::UDiv, 8290cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer SDIV = Instruction::SDiv, 8390cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer FDIV = Instruction::FDiv, 8490cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer UREM = Instruction::URem, 8590cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer SREM = Instruction::SRem, 8690cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer FREM = Instruction::FRem, 8790cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer SHL = Instruction::Shl, 8890cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer LSHR = Instruction::LShr, 8990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer ASHR = Instruction::AShr, 9090cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer AND = Instruction::And, 9190cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer OR = Instruction::Or, 9290cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer XOR = Instruction::Xor, 9390cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer TRUNC = Instruction::Trunc, 9490cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer ZEXT = Instruction::ZExt, 95b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler SEXT = Instruction::SExt, 961e07de352947aaf2f9137113cc594d8204da2b77Reed Kotler FPTOUI = Instruction::FPToUI, 97b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler FPTOSI = Instruction::FPToSI, 98b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler UITOFP = Instruction::UIToFP, 99b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler SITOFP = Instruction::SIToFP, 100b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler FPTRUNC = Instruction::FPTrunc, 101b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler FPEXT = Instruction::FPExt, 102b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler PTRTOINT = Instruction::PtrToInt, 103b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler INTTOPTR = Instruction::IntToPtr, 104b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler BITCAST = Instruction::BitCast, 105b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler ICMPEQ, ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE, 106b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ, 107b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE, 108b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE, 109b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT, 110b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler SHUFFLE, SELECT, GEP, CALL, CONSTANT, 111b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler INSERTVALUE, EXTRACTVALUE, EMPTY, TOMBSTONE }; 112b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler 113b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler ExpressionOpcode opcode; 114b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler const Type* type; 115b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler SmallVector<uint32_t, 4> varargs; 116b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler Value *function; 117b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler 118b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler Expression() { } 119b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler Expression(ExpressionOpcode o) : opcode(o) { } 120b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler 1215ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool operator==(const Expression &other) const { 1225ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (opcode != other.opcode) 123f8b0a08b6a2e2f4eacdb05eae9a8dd704b692b55Reed Kotler return false; 1245ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka else if (opcode == EMPTY || opcode == TOMBSTONE) 1255ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return true; 1265ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka else if (type != other.type) 12790cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer return false; 1285ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka else if (function != other.function) 12990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer return false; 1305ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka else { 1315ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (varargs.size() != other.varargs.size()) 1325ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return false; 1335ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1345ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (size_t i = 0; i < varargs.size(); ++i) 1355ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (varargs[i] != other.varargs[i]) 1365ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return false; 1375ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1385ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return true; 1395ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 1405ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 1415ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1425ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool operator!=(const Expression &other) const { 1435ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return !(*this == other); 144b359bda93d410623bbbc96dc9968d94447169a79Reed Kotler } 145b359bda93d410623bbbc96dc9968d94447169a79Reed Kotler }; 146b359bda93d410623bbbc96dc9968d94447169a79Reed Kotler 147b359bda93d410623bbbc96dc9968d94447169a79Reed Kotler class ValueTable { 148b359bda93d410623bbbc96dc9968d94447169a79Reed Kotler private: 1495ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka DenseMap<Value*, uint32_t> valueNumbering; 1505ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka DenseMap<Expression, uint32_t> expressionNumbering; 1515ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka AliasAnalysis* AA; 1525ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka MemoryDependenceAnalysis* MD; 1535ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka DominatorTree* DT; 1545ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1555ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t nextValueNumber; 1565ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1575ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression::ExpressionOpcode getOpcode(CmpInst* C); 15836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Expression create_expression(BinaryOperator* BO); 15936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Expression create_expression(CmpInst* C); 16036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Expression create_expression(ShuffleVectorInst* V); 1615ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(ExtractElementInst* C); 1625ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(InsertElementInst* V); 1635ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(SelectInst* V); 1645ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(CastInst* C); 1655ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(GetElementPtrInst* G); 1665ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(CallInst* C); 1675ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(Constant* C); 1685ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(ExtractValueInst* C); 1695ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression create_expression(InsertValueInst* C); 1705ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1715ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t lookup_or_add_call(CallInst* C); 1725ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka public: 1735ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka ValueTable() : nextValueNumber(1) { } 1745ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t lookup_or_add(Value *V); 1751703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler uint32_t lookup(Value *V) const; 1765ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka void add(Value *V, uint32_t num); 1771703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler void clear(); 1785ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka void erase(Value *v); 1791703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler unsigned size(); 1805ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka void setAliasAnalysis(AliasAnalysis* A) { AA = A; } 1811703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler AliasAnalysis *getAliasAnalysis() const { return AA; } 1825ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka void setMemDep(MemoryDependenceAnalysis* M) { MD = M; } 1831703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler void setDomTree(DominatorTree* D) { DT = D; } 1845ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t getNextUnusedValueNumber() { return nextValueNumber; } 1851703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler void verifyRemoved(const Value *) const; 1865ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka }; 1871703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler} 1885ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1891703a714954f9ef0c32415423e2a1e15b152e711Reed Kotlernamespace llvm { 1905ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakatemplate <> struct DenseMapInfo<Expression> { 1911703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler static inline Expression getEmptyKey() { 1925ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return Expression(Expression::EMPTY); 1931703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler } 1945ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1951703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler static inline Expression getTombstoneKey() { 1965ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return Expression(Expression::TOMBSTONE); 1971703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler } 1985ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 1991703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler static unsigned getHashValue(const Expression e) { 2005ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka unsigned hash = e.opcode; 2011703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler 2025ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka hash = ((unsigned)((uintptr_t)e.type >> 4) ^ 2035ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka (unsigned)((uintptr_t)e.type >> 9)); 2045ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2051703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler for (SmallVector<uint32_t, 4>::const_iterator I = e.varargs.begin(), 2065ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka E = e.varargs.end(); I != E; ++I) 2071703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler hash = *I + hash * 37; 2085ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2091703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler hash = ((unsigned)((uintptr_t)e.function >> 4) ^ 2105ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka (unsigned)((uintptr_t)e.function >> 9)) + 2115ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka hash * 37; 2125ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2131703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler return hash; 2145ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 2151703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler static bool isEqual(const Expression &LHS, const Expression &RHS) { 2165ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return LHS == RHS; 2171703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler } 2185ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka}; 2191703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler 2205ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakatemplate <> 2211703a714954f9ef0c32415423e2a1e15b152e711Reed Kotlerstruct isPodLike<Expression> { static const bool value = true; }; 2225ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2231703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler} 2245ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2251703a714954f9ef0c32415423e2a1e15b152e711Reed Kotler//===----------------------------------------------------------------------===// 2265ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// ValueTable Internal Functions 2275ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka//===----------------------------------------------------------------------===// 2285ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2295ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) { 2305ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (isa<ICmpInst>(C)) { 2315ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka switch (C->getPredicate()) { 2325ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka default: // THIS SHOULD NEVER HAPPEN 2335ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka llvm_unreachable("Comparison with unknown predicate?"); 2345ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_EQ: return Expression::ICMPEQ; 2355ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_NE: return Expression::ICMPNE; 2365ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_UGT: return Expression::ICMPUGT; 2375ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_UGE: return Expression::ICMPUGE; 2385ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_ULT: return Expression::ICMPULT; 2395ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_ULE: return Expression::ICMPULE; 2405ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_SGT: return Expression::ICMPSGT; 2415ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_SGE: return Expression::ICMPSGE; 2425ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_SLT: return Expression::ICMPSLT; 2435ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case ICmpInst::ICMP_SLE: return Expression::ICMPSLE; 2445ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 2455ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } else { 2465ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka switch (C->getPredicate()) { 2475ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka default: // THIS SHOULD NEVER HAPPEN 2485ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka llvm_unreachable("Comparison with unknown predicate?"); 2495ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case FCmpInst::FCMP_OEQ: return Expression::FCMPOEQ; 2505ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case FCmpInst::FCMP_OGT: return Expression::FCMPOGT; 25190cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_OGE: return Expression::FCMPOGE; 25290cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_OLT: return Expression::FCMPOLT; 25390cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_OLE: return Expression::FCMPOLE; 25490cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_ONE: return Expression::FCMPONE; 25590cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_ORD: return Expression::FCMPORD; 25690cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_UNO: return Expression::FCMPUNO; 2575ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case FCmpInst::FCMP_UEQ: return Expression::FCMPUEQ; 25890cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_UGT: return Expression::FCMPUGT; 25990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_UGE: return Expression::FCMPUGE; 26090cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer case FCmpInst::FCMP_ULT: return Expression::FCMPULT; 2615ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case FCmpInst::FCMP_ULE: return Expression::FCMPULE; 2625ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case FCmpInst::FCMP_UNE: return Expression::FCMPUNE; 2635ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 2645ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 2655ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 2665ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2675ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(CallInst* C) { 2685ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 2695ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2705ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = C->getType(); 2715ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = C->getCalledFunction(); 2725ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = Expression::CALL; 2735ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2745ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (CallInst::op_iterator I = C->op_begin()+1, E = C->op_end(); 2755ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka I != E; ++I) 2765ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(*I)); 2775ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2785ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 2795ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 2805ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2815ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(BinaryOperator* BO) { 2825ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 2835ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(BO->getOperand(0))); 2845ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(BO->getOperand(1))); 2855ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 2865ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = BO->getType(); 2875ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = static_cast<Expression::ExpressionOpcode>(BO->getOpcode()); 2885ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2895ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 2905ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 2915ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2925ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(CmpInst* C) { 2935ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 2945ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 2955ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(C->getOperand(0))); 2965ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(C->getOperand(1))); 2975ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 2985ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = C->getType(); 2995ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = getOpcode(C); 3005ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3015ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 3025ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 3035ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3045ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(CastInst* C) { 3055ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 3065ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3075ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(C->getOperand(0))); 3085ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 3095ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = C->getType(); 3105ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = static_cast<Expression::ExpressionOpcode>(C->getOpcode()); 3115ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3125ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 3135ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 3145ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3155ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(ShuffleVectorInst* S) { 3165ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 3175ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3185ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(S->getOperand(0))); 3195ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(S->getOperand(1))); 3205ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(S->getOperand(2))); 3215ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 3225ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = S->getType(); 3235ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = Expression::SHUFFLE; 3245ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3255ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 3265ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 3275ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3285ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(ExtractElementInst* E) { 3295ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 3305ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3315ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(E->getOperand(0))); 3325ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(E->getOperand(1))); 3335ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 3345ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = E->getType(); 3355ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = Expression::EXTRACT; 3365ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3375ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 3385ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 3395ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3405ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(InsertElementInst* I) { 3415ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 3425ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3435ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(I->getOperand(0))); 3445ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(I->getOperand(1))); 3455ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(I->getOperand(2))); 3465ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 3475ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = I->getType(); 3485ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = Expression::INSERT; 3495ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 350dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return e; 3515ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 3525ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3535ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(SelectInst* I) { 3545ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 3555ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3565ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(I->getCondition())); 3575ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(I->getTrueValue())); 3585ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(I->getFalseValue())); 3595ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 3605ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = I->getType(); 3615ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = Expression::SELECT; 3625ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3635ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 3645ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 3655ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3665ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(GetElementPtrInst* G) { 3675ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 3685ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3695ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(G->getPointerOperand())); 3705ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 3715ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = G->getType(); 3725ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = Expression::GEP; 3735ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3745ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (GetElementPtrInst::op_iterator I = G->idx_begin(), E = G->idx_end(); 3755ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka I != E; ++I) 3765ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(*I)); 3775ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3785ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 3795ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 3805ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3815ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(ExtractValueInst* E) { 3825ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 3835ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3845ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(E->getAggregateOperand())); 3855ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (ExtractValueInst::idx_iterator II = E->idx_begin(), IE = E->idx_end(); 3865ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka II != IE; ++II) 3875ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(*II); 3885ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 3895ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = E->getType(); 3905ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = Expression::EXTRACTVALUE; 3915ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3925ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 3935ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 3945ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3955ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaExpression ValueTable::create_expression(InsertValueInst* E) { 3965ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression e; 3975ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 3985ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(E->getAggregateOperand())); 3995ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(lookup_or_add(E->getInsertedValueOperand())); 4005ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (InsertValueInst::idx_iterator II = E->idx_begin(), IE = E->idx_end(); 4015ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka II != IE; ++II) 4025ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.varargs.push_back(*II); 4035ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.function = 0; 4045ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.type = E->getType(); 4055ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e.opcode = Expression::INSERTVALUE; 4065ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 4075ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 4085ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 4095ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 4105ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka//===----------------------------------------------------------------------===// 4115ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// ValueTable External Functions 4125ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka//===----------------------------------------------------------------------===// 4135ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 4145ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// add - Insert a value into the table with a specified value number. 4155ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakavoid ValueTable::add(Value *V, uint32_t num) { 4165ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering.insert(std::make_pair(V, num)); 4175ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 4185ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 4195ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakauint32_t ValueTable::lookup_or_add_call(CallInst* C) { 4205ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (AA->doesNotAccessMemory(C)) { 4215ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression exp = create_expression(C); 4225ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t& e = expressionNumbering[exp]; 4235ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!e) e = nextValueNumber++; 4245ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[C] = e; 4256ff59a16a05d43fdda587ce600b5b42a63cf3d33Akira Hatanaka return e; 4266ff59a16a05d43fdda587ce600b5b42a63cf3d33Akira Hatanaka } else if (AA->onlyReadsMemory(C)) { 427dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines Expression exp = create_expression(C); 4285ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t& e = expressionNumbering[exp]; 4295ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!e) { 43036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines e = nextValueNumber++; 4315ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[C] = e; 4325ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 4335ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 4345ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!MD) { 4355ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka e = nextValueNumber++; 4365ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[C] = e; 4375ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 43890cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer } 43990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer 440dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines MemDepResult local_dep = MD->getDependency(C); 441dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines 4425ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!local_dep.isDef() && !local_dep.isNonLocal()) { 443b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler valueNumbering[C] = nextValueNumber; 44436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines return nextValueNumber++; 44536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines } 44636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines 44736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (local_dep.isDef()) { 44836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines CallInst* local_cdep = cast<CallInst>(local_dep.getInst()); 44936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines 45036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (local_cdep->getNumOperands() != C->getNumOperands()) { 45136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines valueNumbering[C] = nextValueNumber; 45236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines return nextValueNumber++; 45336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines } 45436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines 45536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines for (unsigned i = 1; i < C->getNumOperands(); ++i) { 45636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines uint32_t c_vn = lookup_or_add(C->getOperand(i)); 45736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines uint32_t cd_vn = lookup_or_add(local_cdep->getOperand(i)); 45836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (c_vn != cd_vn) { 45936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines valueNumbering[C] = nextValueNumber; 46036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines return nextValueNumber++; 46136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines } 46236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines } 46336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines 46436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines uint32_t v = lookup_or_add(local_cdep); 46536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines valueNumbering[C] = v; 46636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines return v; 467b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler } 468dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines 469dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines // Non-local case. 470dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines const MemoryDependenceAnalysis::NonLocalDepInfo &deps = 471dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines MD->getNonLocalCallDependency(CallSite(C)); 472dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines // FIXME: call/call dependencies for readonly calls should return def, not 473dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines // clobber! Move the checking logic to MemDep! 474b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler CallInst* cdep = 0; 475b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler 476b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler // Check to see if we have a single dominating call instruction that is 477b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler // identical to C. 478b1fa7d4d26533bdd021c3269d14c30eb6096fb7aReed Kotler for (unsigned i = 0, e = deps.size(); i != e; ++i) { 47990cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer const NonLocalDepEntry *I = &deps[i]; 48090cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer // Ignore non-local dependencies. 48190cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer if (I->getResult().isNonLocal()) 48290cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer continue; 48390cd06e90be1db06bc4812ae9ec96b6638847285Benjamin Kramer 484dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines // We don't handle non-depedencies. If we already have a call, reject 485dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines // instruction dependencies. 486bf00bf9ad2f07c5c06986930842ace28b8fb2518Reed Kotler if (I->getResult().isClobber() || cdep != 0) { 487bf00bf9ad2f07c5c06986930842ace28b8fb2518Reed Kotler cdep = 0; 488dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines break; 489dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines } 490dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines 4915ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka CallInst *NonLocalDepCall = dyn_cast<CallInst>(I->getResult().getInst()); 4925ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // FIXME: All duplicated with non-local case. 4935ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (NonLocalDepCall && DT->properlyDominates(I->getBB(), C->getParent())){ 4945ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka cdep = NonLocalDepCall; 4955ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka continue; 4965ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 4975ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 4985ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka cdep = 0; 4995ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 5005ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 5015ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 5026ff59a16a05d43fdda587ce600b5b42a63cf3d33Akira Hatanaka if (!cdep) { 5036ff59a16a05d43fdda587ce600b5b42a63cf3d33Akira Hatanaka valueNumbering[C] = nextValueNumber; 5046ff59a16a05d43fdda587ce600b5b42a63cf3d33Akira Hatanaka return nextValueNumber++; 5056ff59a16a05d43fdda587ce600b5b42a63cf3d33Akira Hatanaka } 5065ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 5075ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (cdep->getNumOperands() != C->getNumOperands()) { 5085ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[C] = nextValueNumber; 5095ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return nextValueNumber++; 5105ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 5115ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (unsigned i = 1; i < C->getNumOperands(); ++i) { 5125ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t c_vn = lookup_or_add(C->getOperand(i)); 5135ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t cd_vn = lookup_or_add(cdep->getOperand(i)); 5145ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (c_vn != cd_vn) { 5155ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[C] = nextValueNumber; 5165ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return nextValueNumber++; 5175ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 5185ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 5195ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 5205ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t v = lookup_or_add(cdep); 5215ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[C] = v; 5225ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return v; 5235ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 5245ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } else { 5255ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[C] = nextValueNumber; 5265ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return nextValueNumber++; 5275ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 5285ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 5295ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 5305ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// lookup_or_add - Returns the value number for the specified value, assigning 5315ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// it a new number if it did not have one before. 5325ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakauint32_t ValueTable::lookup_or_add(Value *V) { 5335ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V); 5345ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (VI != valueNumbering.end()) 5355ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return VI->second; 5365ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 5375ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!isa<Instruction>(V)) { 5385ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[V] = nextValueNumber; 5395ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return nextValueNumber++; 5405ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 5415ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 5425ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Instruction* I = cast<Instruction>(V); 5435ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Expression exp; 5445ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka switch (I->getOpcode()) { 54536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines case Instruction::Call: 5465ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return lookup_or_add_call(cast<CallInst>(I)); 5475ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::Add: 5485ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FAdd: 5495ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::Sub: 5505ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FSub: 5515ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::Mul: 5525ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FMul: 5535ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::UDiv: 5545ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::SDiv: 5555ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FDiv: 5565ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::URem: 5575ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::SRem: 5585ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FRem: 5595ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::Shl: 5605ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::LShr: 5615ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::AShr: 5625ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::And: 5635ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::Or : 5645ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::Xor: 5655ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<BinaryOperator>(I)); 5665ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 5675ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::ICmp: 5685ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FCmp: 5695ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<CmpInst>(I)); 5705ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 5715ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::Trunc: 5725ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::ZExt: 5735ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::SExt: 5745ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FPToUI: 5755ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FPToSI: 5765ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::UIToFP: 5775ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::SIToFP: 5785ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FPTrunc: 5795ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::FPExt: 5805ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::PtrToInt: 5815ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::IntToPtr: 5825ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::BitCast: 5835ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<CastInst>(I)); 5845ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 5855ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::Select: 5865ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<SelectInst>(I)); 5875ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 5885ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::ExtractElement: 5895ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<ExtractElementInst>(I)); 5905ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 5915ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::InsertElement: 5925ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<InsertElementInst>(I)); 5935ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 5945ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::ShuffleVector: 5955ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<ShuffleVectorInst>(I)); 5965ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 5975ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::ExtractValue: 5985ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<ExtractValueInst>(I)); 5995ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 6005ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::InsertValue: 6015ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<InsertValueInst>(I)); 6025ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 6035ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka case Instruction::GetElementPtr: 6045ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka exp = create_expression(cast<GetElementPtrInst>(I)); 6055ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka break; 6065ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka default: 60736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines valueNumbering[V] = nextValueNumber; 6085ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return nextValueNumber++; 6095ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 6105ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6115ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka uint32_t& e = expressionNumbering[exp]; 6125ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!e) e = nextValueNumber++; 6135ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering[V] = e; 6145ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return e; 6155ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 6165ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6175ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// lookup - Returns the value number of the specified value. Fails if 6185ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// the value has not yet been numbered. 6195ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakauint32_t ValueTable::lookup(Value *V) const { 6205ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka DenseMap<Value*, uint32_t>::const_iterator VI = valueNumbering.find(V); 6215ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka assert(VI != valueNumbering.end() && "Value not numbered?"); 6225ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return VI->second; 6235ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 6245ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6255ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// clear - Remove all entries from the ValueTable 6265ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakavoid ValueTable::clear() { 6275ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering.clear(); 6285ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka expressionNumbering.clear(); 6295ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka nextValueNumber = 1; 6305ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 6315ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6325ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// erase - Remove a value from the value numbering 6335ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakavoid ValueTable::erase(Value *V) { 6345ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka valueNumbering.erase(V); 6355ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 6365ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6375ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// verifyRemoved - Verify that the value is removed from all internal data 6385ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// structures. 6395ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakavoid ValueTable::verifyRemoved(const Value *V) const { 6405ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (DenseMap<Value*, uint32_t>::const_iterator 6415ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka I = valueNumbering.begin(), E = valueNumbering.end(); I != E; ++I) { 6425ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka assert(I->first != V && "Inst still occurs in value numbering map!"); 6435ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 6445ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 6455ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6465ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka//===----------------------------------------------------------------------===// 6475ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// GVN Pass 6485ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka//===----------------------------------------------------------------------===// 6495ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6505ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakanamespace { 6515ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka struct ValueNumberScope { 6525ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka ValueNumberScope* parent; 6535ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka DenseMap<uint32_t, Value*> table; 6545ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6555ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka ValueNumberScope(ValueNumberScope* p) : parent(p) { } 6565ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka }; 6575ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 6585ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6595ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakanamespace { 6605ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6615ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka class GVN : public FunctionPass { 6625ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool runOnFunction(Function &F); 6635ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka public: 6645ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka static char ID; // Pass identification, replacement for typeid 6655ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka explicit GVN(bool noloads = false) 6665ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka : FunctionPass(&ID), NoLoads(noloads), MD(0) { } 6675ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6685ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka private: 6695ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool NoLoads; 6705ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka MemoryDependenceAnalysis *MD; 67136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines DominatorTree *DT; 6725ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6735ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka ValueTable VN; 6745ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka DenseMap<BasicBlock*, ValueNumberScope*> localAvail; 6755ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6765ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // List of critical edges to be split between iterations. 6775ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka SmallVector<std::pair<TerminatorInst*, unsigned>, 4> toSplit; 6785ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6795ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // This transformation requires dominator postdominator info 6805ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka virtual void getAnalysisUsage(AnalysisUsage &AU) const { 6815ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka AU.addRequired<DominatorTree>(); 6825ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!NoLoads) 6835ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka AU.addRequired<MemoryDependenceAnalysis>(); 6845ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka AU.addRequired<AliasAnalysis>(); 6855ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6865ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka AU.addPreserved<DominatorTree>(); 6875ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka AU.addPreserved<AliasAnalysis>(); 6885ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 6895ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 6905ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // Helper fuctions 6915ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // FIXME: eliminate or document these better 6925ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool processLoad(LoadInst* L, 6935ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka SmallVectorImpl<Instruction*> &toErase); 6945ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool processInstruction(Instruction *I, 6955ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka SmallVectorImpl<Instruction*> &toErase); 6965ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool processNonLocalLoad(LoadInst* L, 6975ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka SmallVectorImpl<Instruction*> &toErase); 6985ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool processBlock(BasicBlock *BB); 6995ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka void dump(DenseMap<uint32_t, Value*>& d); 7005ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool iterateOnFunction(Function &F); 7015ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Value *CollapsePhi(PHINode* p); 7025ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool performPRE(Function& F); 7035ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Value *lookupNumber(BasicBlock *BB, uint32_t num); 7045ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka void cleanupGlobalSets(); 7055ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka void verifyRemoved(const Instruction *I) const; 7065ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka bool splitCriticalEdges(); 7075ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka }; 7085ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7095ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka char GVN::ID = 0; 7105ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 7115ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7125ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka// createGVNPass - The public interface to this file... 7135ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaFunctionPass *llvm::createGVNPass(bool NoLoads) { 7145ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return new GVN(NoLoads); 715b109ea8245e2948ea6d06a6e6cbab7c6788da211Akira Hatanaka} 716b109ea8245e2948ea6d06a6e6cbab7c6788da211Akira Hatanaka 7175ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakastatic RegisterPass<GVN> X("gvn", 7185ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka "Global Value Numbering"); 7195ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7205ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakavoid GVN::dump(DenseMap<uint32_t, Value*>& d) { 7215ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka errs() << "{\n"; 7225ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (DenseMap<uint32_t, Value*>::iterator I = d.begin(), 723b0ee97a366a07c05b2c8ab314e29f5e72a9b7bfbReed Kotler E = d.end(); I != E; ++I) { 7245ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka errs() << I->first << "\n"; 7255ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka I->second->dump(); 7265ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 7275ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka errs() << "}\n"; 7285ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 7295ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7305ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakastatic bool isSafeReplacement(PHINode* p, Instruction *inst) { 7315ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!isa<PHINode>(inst)) 7325ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return true; 7335ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 734b0ee97a366a07c05b2c8ab314e29f5e72a9b7bfbReed Kotler for (Instruction::use_iterator UI = p->use_begin(), E = p->use_end(); 735b0ee97a366a07c05b2c8ab314e29f5e72a9b7bfbReed Kotler UI != E; ++UI) 7365ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (PHINode* use_phi = dyn_cast<PHINode>(UI)) 7375ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (use_phi->getParent() == inst->getParent()) 7385ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return false; 739b109ea8245e2948ea6d06a6e6cbab7c6788da211Akira Hatanaka 740b109ea8245e2948ea6d06a6e6cbab7c6788da211Akira Hatanaka return true; 7415ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 7425ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7435ac065a79767cc112eba63136183b7103765d0d3Akira HatanakaValue *GVN::CollapsePhi(PHINode *PN) { 7445ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Value *ConstVal = PN->hasConstantValue(DT); 7455ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!ConstVal) return 0; 7465ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7475ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka Instruction *Inst = dyn_cast<Instruction>(ConstVal); 7485ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!Inst) 7495ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return ConstVal; 7505ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7515ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (DT->dominates(Inst, PN)) 7525ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (isSafeReplacement(PN, Inst)) 7535ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return Inst; 7545ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return 0; 7555ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka} 7565ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7575ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// IsValueFullyAvailableInBlock - Return true if we can prove that the value 7585ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// we're analyzing is fully available in the specified block. As we go, keep 7595ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// track of which blocks we know are fully alive in FullyAvailableBlocks. This 7605ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// map is actually a tri-state map with the following values: 7615ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// 0) we know the block *is not* fully available. 7625ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// 1) we know the block *is* fully available. 7635ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// 2) we do not know whether the block is fully available or not, but we are 7645ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka/// currently speculating that it will be. 76536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 3) we are speculating for this block and have used that to speculate for 76636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// other blocks. 7675ac065a79767cc112eba63136183b7103765d0d3Akira Hatanakastatic bool IsValueFullyAvailableInBlock(BasicBlock *BB, 7685ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka DenseMap<BasicBlock*, char> &FullyAvailableBlocks) { 7695ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // Optimistically assume that the block is fully available and check to see 7705ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // if we already know about this block in one lookup. 7715ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka std::pair<DenseMap<BasicBlock*, char>::iterator, char> IV = 7725ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka FullyAvailableBlocks.insert(std::make_pair(BB, 2)); 7735ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7745ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // If the entry already existed for this block, return the precomputed value. 7755ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (!IV.second) { 7765ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // If this is a speculative "available" value, mark it as being used for 7775ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // speculation of other blocks. 7785ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (IV.first->second == 2) 7795ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka IV.first->second = 3; 7805ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka return IV.first->second != 0; 7815ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka } 7825ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7835ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // Otherwise, see if it is fully available in all predecessors. 7845ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka pred_iterator PI = pred_begin(BB), PE = pred_end(BB); 7855ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7865ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka // If this block has no predecessors, it isn't live-in here. 7875ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka if (PI == PE) 7885ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka goto SpeculationFailure; 7895ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka 7905ac065a79767cc112eba63136183b7103765d0d3Akira Hatanaka for (; PI != PE; ++PI) 791 // If the value isn't fully available in one of our predecessors, then it 792 // isn't fully available in this block either. Undo our previous 793 // optimistic assumption and bail out. 794 if (!IsValueFullyAvailableInBlock(*PI, FullyAvailableBlocks)) 795 goto SpeculationFailure; 796 797 return true; 798 799// SpeculationFailure - If we get here, we found out that this is not, after 800// all, a fully-available block. We have a problem if we speculated on this and 801// used the speculation to mark other blocks as available. 802SpeculationFailure: 803 char &BBVal = FullyAvailableBlocks[BB]; 804 805 // If we didn't speculate on this, just return with it set to false. 806 if (BBVal == 2) { 807 BBVal = 0; 808 return false; 809 } 810 811 // If we did speculate on this value, we could have blocks set to 1 that are 812 // incorrect. Walk the (transitive) successors of this block and mark them as 813 // 0 if set to one. 814 SmallVector<BasicBlock*, 32> BBWorklist; 815 BBWorklist.push_back(BB); 816 817 do { 818 BasicBlock *Entry = BBWorklist.pop_back_val(); 819 // Note that this sets blocks to 0 (unavailable) if they happen to not 820 // already be in FullyAvailableBlocks. This is safe. 821 char &EntryVal = FullyAvailableBlocks[Entry]; 822 if (EntryVal == 0) continue; // Already unavailable. 823 824 // Mark as unavailable. 825 EntryVal = 0; 826 827 for (succ_iterator I = succ_begin(Entry), E = succ_end(Entry); I != E; ++I) 828 BBWorklist.push_back(*I); 829 } while (!BBWorklist.empty()); 830 831 return false; 832} 833 834 835/// CanCoerceMustAliasedValueToLoad - Return true if 836/// CoerceAvailableValueToLoadType will succeed. 837static bool CanCoerceMustAliasedValueToLoad(Value *StoredVal, 838 const Type *LoadTy, 839 const TargetData &TD) { 840 // If the loaded or stored value is an first class array or struct, don't try 841 // to transform them. We need to be able to bitcast to integer. 842 if (LoadTy->isStructTy() || LoadTy->isArrayTy() || 843 StoredVal->getType()->isStructTy() || 844 StoredVal->getType()->isArrayTy()) 845 return false; 846 847 // The store has to be at least as big as the load. 848 if (TD.getTypeSizeInBits(StoredVal->getType()) < 849 TD.getTypeSizeInBits(LoadTy)) 850 return false; 851 852 return true; 853} 854 855 856/// CoerceAvailableValueToLoadType - If we saw a store of a value to memory, and 857/// then a load from a must-aliased pointer of a different type, try to coerce 858/// the stored value. LoadedTy is the type of the load we want to replace and 859/// InsertPt is the place to insert new instructions. 860/// 861/// If we can't do it, return null. 862static Value *CoerceAvailableValueToLoadType(Value *StoredVal, 863 const Type *LoadedTy, 864 Instruction *InsertPt, 865 const TargetData &TD) { 866 if (!CanCoerceMustAliasedValueToLoad(StoredVal, LoadedTy, TD)) 867 return 0; 868 869 const Type *StoredValTy = StoredVal->getType(); 870 871 uint64_t StoreSize = TD.getTypeSizeInBits(StoredValTy); 872 uint64_t LoadSize = TD.getTypeSizeInBits(LoadedTy); 873 874 // If the store and reload are the same size, we can always reuse it. 875 if (StoreSize == LoadSize) { 876 if (StoredValTy->isPointerTy() && LoadedTy->isPointerTy()) { 877 // Pointer to Pointer -> use bitcast. 878 return new BitCastInst(StoredVal, LoadedTy, "", InsertPt); 879 } 880 881 // Convert source pointers to integers, which can be bitcast. 882 if (StoredValTy->isPointerTy()) { 883 StoredValTy = TD.getIntPtrType(StoredValTy->getContext()); 884 StoredVal = new PtrToIntInst(StoredVal, StoredValTy, "", InsertPt); 885 } 886 887 const Type *TypeToCastTo = LoadedTy; 888 if (TypeToCastTo->isPointerTy()) 889 TypeToCastTo = TD.getIntPtrType(StoredValTy->getContext()); 890 891 if (StoredValTy != TypeToCastTo) 892 StoredVal = new BitCastInst(StoredVal, TypeToCastTo, "", InsertPt); 893 894 // Cast to pointer if the load needs a pointer type. 895 if (LoadedTy->isPointerTy()) 896 StoredVal = new IntToPtrInst(StoredVal, LoadedTy, "", InsertPt); 897 898 return StoredVal; 899 } 900 901 // If the loaded value is smaller than the available value, then we can 902 // extract out a piece from it. If the available value is too small, then we 903 // can't do anything. 904 assert(StoreSize >= LoadSize && "CanCoerceMustAliasedValueToLoad fail"); 905 906 // Convert source pointers to integers, which can be manipulated. 907 if (StoredValTy->isPointerTy()) { 908 StoredValTy = TD.getIntPtrType(StoredValTy->getContext()); 909 StoredVal = new PtrToIntInst(StoredVal, StoredValTy, "", InsertPt); 910 } 911 912 // Convert vectors and fp to integer, which can be manipulated. 913 if (!StoredValTy->isIntegerTy()) { 914 StoredValTy = IntegerType::get(StoredValTy->getContext(), StoreSize); 915 StoredVal = new BitCastInst(StoredVal, StoredValTy, "", InsertPt); 916 } 917 918 // If this is a big-endian system, we need to shift the value down to the low 919 // bits so that a truncate will work. 920 if (TD.isBigEndian()) { 921 Constant *Val = ConstantInt::get(StoredVal->getType(), StoreSize-LoadSize); 922 StoredVal = BinaryOperator::CreateLShr(StoredVal, Val, "tmp", InsertPt); 923 } 924 925 // Truncate the integer to the right size now. 926 const Type *NewIntTy = IntegerType::get(StoredValTy->getContext(), LoadSize); 927 StoredVal = new TruncInst(StoredVal, NewIntTy, "trunc", InsertPt); 928 929 if (LoadedTy == NewIntTy) 930 return StoredVal; 931 932 // If the result is a pointer, inttoptr. 933 if (LoadedTy->isPointerTy()) 934 return new IntToPtrInst(StoredVal, LoadedTy, "inttoptr", InsertPt); 935 936 // Otherwise, bitcast. 937 return new BitCastInst(StoredVal, LoadedTy, "bitcast", InsertPt); 938} 939 940/// GetBaseWithConstantOffset - Analyze the specified pointer to see if it can 941/// be expressed as a base pointer plus a constant offset. Return the base and 942/// offset to the caller. 943static Value *GetBaseWithConstantOffset(Value *Ptr, int64_t &Offset, 944 const TargetData &TD) { 945 Operator *PtrOp = dyn_cast<Operator>(Ptr); 946 if (PtrOp == 0) return Ptr; 947 948 // Just look through bitcasts. 949 if (PtrOp->getOpcode() == Instruction::BitCast) 950 return GetBaseWithConstantOffset(PtrOp->getOperand(0), Offset, TD); 951 952 // If this is a GEP with constant indices, we can look through it. 953 GEPOperator *GEP = dyn_cast<GEPOperator>(PtrOp); 954 if (GEP == 0 || !GEP->hasAllConstantIndices()) return Ptr; 955 956 gep_type_iterator GTI = gep_type_begin(GEP); 957 for (User::op_iterator I = GEP->idx_begin(), E = GEP->idx_end(); I != E; 958 ++I, ++GTI) { 959 ConstantInt *OpC = cast<ConstantInt>(*I); 960 if (OpC->isZero()) continue; 961 962 // Handle a struct and array indices which add their offset to the pointer. 963 if (const StructType *STy = dyn_cast<StructType>(*GTI)) { 964 Offset += TD.getStructLayout(STy)->getElementOffset(OpC->getZExtValue()); 965 } else { 966 uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType()); 967 Offset += OpC->getSExtValue()*Size; 968 } 969 } 970 971 // Re-sign extend from the pointer size if needed to get overflow edge cases 972 // right. 973 unsigned PtrSize = TD.getPointerSizeInBits(); 974 if (PtrSize < 64) 975 Offset = (Offset << (64-PtrSize)) >> (64-PtrSize); 976 977 return GetBaseWithConstantOffset(GEP->getPointerOperand(), Offset, TD); 978} 979 980 981/// AnalyzeLoadFromClobberingWrite - This function is called when we have a 982/// memdep query of a load that ends up being a clobbering memory write (store, 983/// memset, memcpy, memmove). This means that the write *may* provide bits used 984/// by the load but we can't be sure because the pointers don't mustalias. 985/// 986/// Check this case to see if there is anything more we can do before we give 987/// up. This returns -1 if we have to give up, or a byte number in the stored 988/// value of the piece that feeds the load. 989static int AnalyzeLoadFromClobberingWrite(const Type *LoadTy, Value *LoadPtr, 990 Value *WritePtr, 991 uint64_t WriteSizeInBits, 992 const TargetData &TD) { 993 // If the loaded or stored value is an first class array or struct, don't try 994 // to transform them. We need to be able to bitcast to integer. 995 if (LoadTy->isStructTy() || LoadTy->isArrayTy()) 996 return -1; 997 998 int64_t StoreOffset = 0, LoadOffset = 0; 999 Value *StoreBase = GetBaseWithConstantOffset(WritePtr, StoreOffset, TD); 1000 Value *LoadBase = 1001 GetBaseWithConstantOffset(LoadPtr, LoadOffset, TD); 1002 if (StoreBase != LoadBase) 1003 return -1; 1004 1005 // If the load and store are to the exact same address, they should have been 1006 // a must alias. AA must have gotten confused. 1007 // FIXME: Study to see if/when this happens. One case is forwarding a memset 1008 // to a load from the base of the memset. 1009#if 0 1010 if (LoadOffset == StoreOffset) { 1011 dbgs() << "STORE/LOAD DEP WITH COMMON POINTER MISSED:\n" 1012 << "Base = " << *StoreBase << "\n" 1013 << "Store Ptr = " << *WritePtr << "\n" 1014 << "Store Offs = " << StoreOffset << "\n" 1015 << "Load Ptr = " << *LoadPtr << "\n"; 1016 abort(); 1017 } 1018#endif 1019 1020 // If the load and store don't overlap at all, the store doesn't provide 1021 // anything to the load. In this case, they really don't alias at all, AA 1022 // must have gotten confused. 1023 // FIXME: Investigate cases where this bails out, e.g. rdar://7238614. Then 1024 // remove this check, as it is duplicated with what we have below. 1025 uint64_t LoadSize = TD.getTypeSizeInBits(LoadTy); 1026 1027 if ((WriteSizeInBits & 7) | (LoadSize & 7)) 1028 return -1; 1029 uint64_t StoreSize = WriteSizeInBits >> 3; // Convert to bytes. 1030 LoadSize >>= 3; 1031 1032 1033 bool isAAFailure = false; 1034 if (StoreOffset < LoadOffset) 1035 isAAFailure = StoreOffset+int64_t(StoreSize) <= LoadOffset; 1036 else 1037 isAAFailure = LoadOffset+int64_t(LoadSize) <= StoreOffset; 1038 1039 if (isAAFailure) { 1040#if 0 1041 dbgs() << "STORE LOAD DEP WITH COMMON BASE:\n" 1042 << "Base = " << *StoreBase << "\n" 1043 << "Store Ptr = " << *WritePtr << "\n" 1044 << "Store Offs = " << StoreOffset << "\n" 1045 << "Load Ptr = " << *LoadPtr << "\n"; 1046 abort(); 1047#endif 1048 return -1; 1049 } 1050 1051 // If the Load isn't completely contained within the stored bits, we don't 1052 // have all the bits to feed it. We could do something crazy in the future 1053 // (issue a smaller load then merge the bits in) but this seems unlikely to be 1054 // valuable. 1055 if (StoreOffset > LoadOffset || 1056 StoreOffset+StoreSize < LoadOffset+LoadSize) 1057 return -1; 1058 1059 // Okay, we can do this transformation. Return the number of bytes into the 1060 // store that the load is. 1061 return LoadOffset-StoreOffset; 1062} 1063 1064/// AnalyzeLoadFromClobberingStore - This function is called when we have a 1065/// memdep query of a load that ends up being a clobbering store. 1066static int AnalyzeLoadFromClobberingStore(const Type *LoadTy, Value *LoadPtr, 1067 StoreInst *DepSI, 1068 const TargetData &TD) { 1069 // Cannot handle reading from store of first-class aggregate yet. 1070 if (DepSI->getOperand(0)->getType()->isStructTy() || 1071 DepSI->getOperand(0)->getType()->isArrayTy()) 1072 return -1; 1073 1074 Value *StorePtr = DepSI->getPointerOperand(); 1075 uint64_t StoreSize = TD.getTypeSizeInBits(DepSI->getOperand(0)->getType()); 1076 return AnalyzeLoadFromClobberingWrite(LoadTy, LoadPtr, 1077 StorePtr, StoreSize, TD); 1078} 1079 1080static int AnalyzeLoadFromClobberingMemInst(const Type *LoadTy, Value *LoadPtr, 1081 MemIntrinsic *MI, 1082 const TargetData &TD) { 1083 // If the mem operation is a non-constant size, we can't handle it. 1084 ConstantInt *SizeCst = dyn_cast<ConstantInt>(MI->getLength()); 1085 if (SizeCst == 0) return -1; 1086 uint64_t MemSizeInBits = SizeCst->getZExtValue()*8; 1087 1088 // If this is memset, we just need to see if the offset is valid in the size 1089 // of the memset.. 1090 if (MI->getIntrinsicID() == Intrinsic::memset) 1091 return AnalyzeLoadFromClobberingWrite(LoadTy, LoadPtr, MI->getDest(), 1092 MemSizeInBits, TD); 1093 1094 // If we have a memcpy/memmove, the only case we can handle is if this is a 1095 // copy from constant memory. In that case, we can read directly from the 1096 // constant memory. 1097 MemTransferInst *MTI = cast<MemTransferInst>(MI); 1098 1099 Constant *Src = dyn_cast<Constant>(MTI->getSource()); 1100 if (Src == 0) return -1; 1101 1102 GlobalVariable *GV = dyn_cast<GlobalVariable>(Src->getUnderlyingObject()); 1103 if (GV == 0 || !GV->isConstant()) return -1; 1104 1105 // See if the access is within the bounds of the transfer. 1106 int Offset = AnalyzeLoadFromClobberingWrite(LoadTy, LoadPtr, 1107 MI->getDest(), MemSizeInBits, TD); 1108 if (Offset == -1) 1109 return Offset; 1110 1111 // Otherwise, see if we can constant fold a load from the constant with the 1112 // offset applied as appropriate. 1113 Src = ConstantExpr::getBitCast(Src, 1114 llvm::Type::getInt8PtrTy(Src->getContext())); 1115 Constant *OffsetCst = 1116 ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset); 1117 Src = ConstantExpr::getGetElementPtr(Src, &OffsetCst, 1); 1118 Src = ConstantExpr::getBitCast(Src, PointerType::getUnqual(LoadTy)); 1119 if (ConstantFoldLoadFromConstPtr(Src, &TD)) 1120 return Offset; 1121 return -1; 1122} 1123 1124 1125/// GetStoreValueForLoad - This function is called when we have a 1126/// memdep query of a load that ends up being a clobbering store. This means 1127/// that the store *may* provide bits used by the load but we can't be sure 1128/// because the pointers don't mustalias. Check this case to see if there is 1129/// anything more we can do before we give up. 1130static Value *GetStoreValueForLoad(Value *SrcVal, unsigned Offset, 1131 const Type *LoadTy, 1132 Instruction *InsertPt, const TargetData &TD){ 1133 LLVMContext &Ctx = SrcVal->getType()->getContext(); 1134 1135 uint64_t StoreSize = TD.getTypeSizeInBits(SrcVal->getType())/8; 1136 uint64_t LoadSize = TD.getTypeSizeInBits(LoadTy)/8; 1137 1138 IRBuilder<> Builder(InsertPt->getParent(), InsertPt); 1139 1140 // Compute which bits of the stored value are being used by the load. Convert 1141 // to an integer type to start with. 1142 if (SrcVal->getType()->isPointerTy()) 1143 SrcVal = Builder.CreatePtrToInt(SrcVal, TD.getIntPtrType(Ctx), "tmp"); 1144 if (!SrcVal->getType()->isIntegerTy()) 1145 SrcVal = Builder.CreateBitCast(SrcVal, IntegerType::get(Ctx, StoreSize*8), 1146 "tmp"); 1147 1148 // Shift the bits to the least significant depending on endianness. 1149 unsigned ShiftAmt; 1150 if (TD.isLittleEndian()) 1151 ShiftAmt = Offset*8; 1152 else 1153 ShiftAmt = (StoreSize-LoadSize-Offset)*8; 1154 1155 if (ShiftAmt) 1156 SrcVal = Builder.CreateLShr(SrcVal, ShiftAmt, "tmp"); 1157 1158 if (LoadSize != StoreSize) 1159 SrcVal = Builder.CreateTrunc(SrcVal, IntegerType::get(Ctx, LoadSize*8), 1160 "tmp"); 1161 1162 return CoerceAvailableValueToLoadType(SrcVal, LoadTy, InsertPt, TD); 1163} 1164 1165/// GetMemInstValueForLoad - This function is called when we have a 1166/// memdep query of a load that ends up being a clobbering mem intrinsic. 1167static Value *GetMemInstValueForLoad(MemIntrinsic *SrcInst, unsigned Offset, 1168 const Type *LoadTy, Instruction *InsertPt, 1169 const TargetData &TD){ 1170 LLVMContext &Ctx = LoadTy->getContext(); 1171 uint64_t LoadSize = TD.getTypeSizeInBits(LoadTy)/8; 1172 1173 IRBuilder<> Builder(InsertPt->getParent(), InsertPt); 1174 1175 // We know that this method is only called when the mem transfer fully 1176 // provides the bits for the load. 1177 if (MemSetInst *MSI = dyn_cast<MemSetInst>(SrcInst)) { 1178 // memset(P, 'x', 1234) -> splat('x'), even if x is a variable, and 1179 // independently of what the offset is. 1180 Value *Val = MSI->getValue(); 1181 if (LoadSize != 1) 1182 Val = Builder.CreateZExt(Val, IntegerType::get(Ctx, LoadSize*8)); 1183 1184 Value *OneElt = Val; 1185 1186 // Splat the value out to the right number of bits. 1187 for (unsigned NumBytesSet = 1; NumBytesSet != LoadSize; ) { 1188 // If we can double the number of bytes set, do it. 1189 if (NumBytesSet*2 <= LoadSize) { 1190 Value *ShVal = Builder.CreateShl(Val, NumBytesSet*8); 1191 Val = Builder.CreateOr(Val, ShVal); 1192 NumBytesSet <<= 1; 1193 continue; 1194 } 1195 1196 // Otherwise insert one byte at a time. 1197 Value *ShVal = Builder.CreateShl(Val, 1*8); 1198 Val = Builder.CreateOr(OneElt, ShVal); 1199 ++NumBytesSet; 1200 } 1201 1202 return CoerceAvailableValueToLoadType(Val, LoadTy, InsertPt, TD); 1203 } 1204 1205 // Otherwise, this is a memcpy/memmove from a constant global. 1206 MemTransferInst *MTI = cast<MemTransferInst>(SrcInst); 1207 Constant *Src = cast<Constant>(MTI->getSource()); 1208 1209 // Otherwise, see if we can constant fold a load from the constant with the 1210 // offset applied as appropriate. 1211 Src = ConstantExpr::getBitCast(Src, 1212 llvm::Type::getInt8PtrTy(Src->getContext())); 1213 Constant *OffsetCst = 1214 ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset); 1215 Src = ConstantExpr::getGetElementPtr(Src, &OffsetCst, 1); 1216 Src = ConstantExpr::getBitCast(Src, PointerType::getUnqual(LoadTy)); 1217 return ConstantFoldLoadFromConstPtr(Src, &TD); 1218} 1219 1220 1221 1222struct AvailableValueInBlock { 1223 /// BB - The basic block in question. 1224 BasicBlock *BB; 1225 enum ValType { 1226 SimpleVal, // A simple offsetted value that is accessed. 1227 MemIntrin // A memory intrinsic which is loaded from. 1228 }; 1229 1230 /// V - The value that is live out of the block. 1231 PointerIntPair<Value *, 1, ValType> Val; 1232 1233 /// Offset - The byte offset in Val that is interesting for the load query. 1234 unsigned Offset; 1235 1236 static AvailableValueInBlock get(BasicBlock *BB, Value *V, 1237 unsigned Offset = 0) { 1238 AvailableValueInBlock Res; 1239 Res.BB = BB; 1240 Res.Val.setPointer(V); 1241 Res.Val.setInt(SimpleVal); 1242 Res.Offset = Offset; 1243 return Res; 1244 } 1245 1246 static AvailableValueInBlock getMI(BasicBlock *BB, MemIntrinsic *MI, 1247 unsigned Offset = 0) { 1248 AvailableValueInBlock Res; 1249 Res.BB = BB; 1250 Res.Val.setPointer(MI); 1251 Res.Val.setInt(MemIntrin); 1252 Res.Offset = Offset; 1253 return Res; 1254 } 1255 1256 bool isSimpleValue() const { return Val.getInt() == SimpleVal; } 1257 Value *getSimpleValue() const { 1258 assert(isSimpleValue() && "Wrong accessor"); 1259 return Val.getPointer(); 1260 } 1261 1262 MemIntrinsic *getMemIntrinValue() const { 1263 assert(!isSimpleValue() && "Wrong accessor"); 1264 return cast<MemIntrinsic>(Val.getPointer()); 1265 } 1266 1267 /// MaterializeAdjustedValue - Emit code into this block to adjust the value 1268 /// defined here to the specified type. This handles various coercion cases. 1269 Value *MaterializeAdjustedValue(const Type *LoadTy, 1270 const TargetData *TD) const { 1271 Value *Res; 1272 if (isSimpleValue()) { 1273 Res = getSimpleValue(); 1274 if (Res->getType() != LoadTy) { 1275 assert(TD && "Need target data to handle type mismatch case"); 1276 Res = GetStoreValueForLoad(Res, Offset, LoadTy, BB->getTerminator(), 1277 *TD); 1278 1279 DEBUG(errs() << "GVN COERCED NONLOCAL VAL:\nOffset: " << Offset << " " 1280 << *getSimpleValue() << '\n' 1281 << *Res << '\n' << "\n\n\n"); 1282 } 1283 } else { 1284 Res = GetMemInstValueForLoad(getMemIntrinValue(), Offset, 1285 LoadTy, BB->getTerminator(), *TD); 1286 DEBUG(errs() << "GVN COERCED NONLOCAL MEM INTRIN:\nOffset: " << Offset 1287 << " " << *getMemIntrinValue() << '\n' 1288 << *Res << '\n' << "\n\n\n"); 1289 } 1290 return Res; 1291 } 1292}; 1293 1294/// ConstructSSAForLoadSet - Given a set of loads specified by ValuesPerBlock, 1295/// construct SSA form, allowing us to eliminate LI. This returns the value 1296/// that should be used at LI's definition site. 1297static Value *ConstructSSAForLoadSet(LoadInst *LI, 1298 SmallVectorImpl<AvailableValueInBlock> &ValuesPerBlock, 1299 const TargetData *TD, 1300 const DominatorTree &DT, 1301 AliasAnalysis *AA) { 1302 // Check for the fully redundant, dominating load case. In this case, we can 1303 // just use the dominating value directly. 1304 if (ValuesPerBlock.size() == 1 && 1305 DT.properlyDominates(ValuesPerBlock[0].BB, LI->getParent())) 1306 return ValuesPerBlock[0].MaterializeAdjustedValue(LI->getType(), TD); 1307 1308 // Otherwise, we have to construct SSA form. 1309 SmallVector<PHINode*, 8> NewPHIs; 1310 SSAUpdater SSAUpdate(&NewPHIs); 1311 SSAUpdate.Initialize(LI); 1312 1313 const Type *LoadTy = LI->getType(); 1314 1315 for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i) { 1316 const AvailableValueInBlock &AV = ValuesPerBlock[i]; 1317 BasicBlock *BB = AV.BB; 1318 1319 if (SSAUpdate.HasValueForBlock(BB)) 1320 continue; 1321 1322 SSAUpdate.AddAvailableValue(BB, AV.MaterializeAdjustedValue(LoadTy, TD)); 1323 } 1324 1325 // Perform PHI construction. 1326 Value *V = SSAUpdate.GetValueInMiddleOfBlock(LI->getParent()); 1327 1328 // If new PHI nodes were created, notify alias analysis. 1329 if (V->getType()->isPointerTy()) 1330 for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i) 1331 AA->copyValue(LI, NewPHIs[i]); 1332 1333 return V; 1334} 1335 1336static bool isLifetimeStart(const Instruction *Inst) { 1337 if (const IntrinsicInst* II = dyn_cast<IntrinsicInst>(Inst)) 1338 return II->getIntrinsicID() == Intrinsic::lifetime_start; 1339 return false; 1340} 1341 1342/// processNonLocalLoad - Attempt to eliminate a load whose dependencies are 1343/// non-local by performing PHI construction. 1344bool GVN::processNonLocalLoad(LoadInst *LI, 1345 SmallVectorImpl<Instruction*> &toErase) { 1346 // Find the non-local dependencies of the load. 1347 SmallVector<NonLocalDepResult, 64> Deps; 1348 MD->getNonLocalPointerDependency(LI->getOperand(0), true, LI->getParent(), 1349 Deps); 1350 //DEBUG(dbgs() << "INVESTIGATING NONLOCAL LOAD: " 1351 // << Deps.size() << *LI << '\n'); 1352 1353 // If we had to process more than one hundred blocks to find the 1354 // dependencies, this load isn't worth worrying about. Optimizing 1355 // it will be too expensive. 1356 if (Deps.size() > 100) 1357 return false; 1358 1359 // If we had a phi translation failure, we'll have a single entry which is a 1360 // clobber in the current block. Reject this early. 1361 if (Deps.size() == 1 && Deps[0].getResult().isClobber()) { 1362 DEBUG( 1363 dbgs() << "GVN: non-local load "; 1364 WriteAsOperand(dbgs(), LI); 1365 dbgs() << " is clobbered by " << *Deps[0].getResult().getInst() << '\n'; 1366 ); 1367 return false; 1368 } 1369 1370 // Filter out useless results (non-locals, etc). Keep track of the blocks 1371 // where we have a value available in repl, also keep track of whether we see 1372 // dependencies that produce an unknown value for the load (such as a call 1373 // that could potentially clobber the load). 1374 SmallVector<AvailableValueInBlock, 16> ValuesPerBlock; 1375 SmallVector<BasicBlock*, 16> UnavailableBlocks; 1376 1377 const TargetData *TD = 0; 1378 1379 for (unsigned i = 0, e = Deps.size(); i != e; ++i) { 1380 BasicBlock *DepBB = Deps[i].getBB(); 1381 MemDepResult DepInfo = Deps[i].getResult(); 1382 1383 if (DepInfo.isClobber()) { 1384 // The address being loaded in this non-local block may not be the same as 1385 // the pointer operand of the load if PHI translation occurs. Make sure 1386 // to consider the right address. 1387 Value *Address = Deps[i].getAddress(); 1388 1389 // If the dependence is to a store that writes to a superset of the bits 1390 // read by the load, we can extract the bits we need for the load from the 1391 // stored value. 1392 if (StoreInst *DepSI = dyn_cast<StoreInst>(DepInfo.getInst())) { 1393 if (TD == 0) 1394 TD = getAnalysisIfAvailable<TargetData>(); 1395 if (TD && Address) { 1396 int Offset = AnalyzeLoadFromClobberingStore(LI->getType(), Address, 1397 DepSI, *TD); 1398 if (Offset != -1) { 1399 ValuesPerBlock.push_back(AvailableValueInBlock::get(DepBB, 1400 DepSI->getOperand(0), 1401 Offset)); 1402 continue; 1403 } 1404 } 1405 } 1406 1407 // If the clobbering value is a memset/memcpy/memmove, see if we can 1408 // forward a value on from it. 1409 if (MemIntrinsic *DepMI = dyn_cast<MemIntrinsic>(DepInfo.getInst())) { 1410 if (TD == 0) 1411 TD = getAnalysisIfAvailable<TargetData>(); 1412 if (TD && Address) { 1413 int Offset = AnalyzeLoadFromClobberingMemInst(LI->getType(), Address, 1414 DepMI, *TD); 1415 if (Offset != -1) { 1416 ValuesPerBlock.push_back(AvailableValueInBlock::getMI(DepBB, DepMI, 1417 Offset)); 1418 continue; 1419 } 1420 } 1421 } 1422 1423 UnavailableBlocks.push_back(DepBB); 1424 continue; 1425 } 1426 1427 Instruction *DepInst = DepInfo.getInst(); 1428 1429 // Loading the allocation -> undef. 1430 if (isa<AllocaInst>(DepInst) || isMalloc(DepInst) || 1431 // Loading immediately after lifetime begin -> undef. 1432 isLifetimeStart(DepInst)) { 1433 ValuesPerBlock.push_back(AvailableValueInBlock::get(DepBB, 1434 UndefValue::get(LI->getType()))); 1435 continue; 1436 } 1437 1438 if (StoreInst *S = dyn_cast<StoreInst>(DepInst)) { 1439 // Reject loads and stores that are to the same address but are of 1440 // different types if we have to. 1441 if (S->getOperand(0)->getType() != LI->getType()) { 1442 if (TD == 0) 1443 TD = getAnalysisIfAvailable<TargetData>(); 1444 1445 // If the stored value is larger or equal to the loaded value, we can 1446 // reuse it. 1447 if (TD == 0 || !CanCoerceMustAliasedValueToLoad(S->getOperand(0), 1448 LI->getType(), *TD)) { 1449 UnavailableBlocks.push_back(DepBB); 1450 continue; 1451 } 1452 } 1453 1454 ValuesPerBlock.push_back(AvailableValueInBlock::get(DepBB, 1455 S->getOperand(0))); 1456 continue; 1457 } 1458 1459 if (LoadInst *LD = dyn_cast<LoadInst>(DepInst)) { 1460 // If the types mismatch and we can't handle it, reject reuse of the load. 1461 if (LD->getType() != LI->getType()) { 1462 if (TD == 0) 1463 TD = getAnalysisIfAvailable<TargetData>(); 1464 1465 // If the stored value is larger or equal to the loaded value, we can 1466 // reuse it. 1467 if (TD == 0 || !CanCoerceMustAliasedValueToLoad(LD, LI->getType(),*TD)){ 1468 UnavailableBlocks.push_back(DepBB); 1469 continue; 1470 } 1471 } 1472 ValuesPerBlock.push_back(AvailableValueInBlock::get(DepBB, LD)); 1473 continue; 1474 } 1475 1476 UnavailableBlocks.push_back(DepBB); 1477 continue; 1478 } 1479 1480 // If we have no predecessors that produce a known value for this load, exit 1481 // early. 1482 if (ValuesPerBlock.empty()) return false; 1483 1484 // If all of the instructions we depend on produce a known value for this 1485 // load, then it is fully redundant and we can use PHI insertion to compute 1486 // its value. Insert PHIs and remove the fully redundant value now. 1487 if (UnavailableBlocks.empty()) { 1488 DEBUG(dbgs() << "GVN REMOVING NONLOCAL LOAD: " << *LI << '\n'); 1489 1490 // Perform PHI construction. 1491 Value *V = ConstructSSAForLoadSet(LI, ValuesPerBlock, TD, *DT, 1492 VN.getAliasAnalysis()); 1493 LI->replaceAllUsesWith(V); 1494 1495 if (isa<PHINode>(V)) 1496 V->takeName(LI); 1497 if (V->getType()->isPointerTy()) 1498 MD->invalidateCachedPointerInfo(V); 1499 VN.erase(LI); 1500 toErase.push_back(LI); 1501 NumGVNLoad++; 1502 return true; 1503 } 1504 1505 if (!EnablePRE || !EnableLoadPRE) 1506 return false; 1507 1508 // Okay, we have *some* definitions of the value. This means that the value 1509 // is available in some of our (transitive) predecessors. Lets think about 1510 // doing PRE of this load. This will involve inserting a new load into the 1511 // predecessor when it's not available. We could do this in general, but 1512 // prefer to not increase code size. As such, we only do this when we know 1513 // that we only have to insert *one* load (which means we're basically moving 1514 // the load, not inserting a new one). 1515 1516 SmallPtrSet<BasicBlock *, 4> Blockers; 1517 for (unsigned i = 0, e = UnavailableBlocks.size(); i != e; ++i) 1518 Blockers.insert(UnavailableBlocks[i]); 1519 1520 // Lets find first basic block with more than one predecessor. Walk backwards 1521 // through predecessors if needed. 1522 BasicBlock *LoadBB = LI->getParent(); 1523 BasicBlock *TmpBB = LoadBB; 1524 1525 bool isSinglePred = false; 1526 bool allSingleSucc = true; 1527 while (TmpBB->getSinglePredecessor()) { 1528 isSinglePred = true; 1529 TmpBB = TmpBB->getSinglePredecessor(); 1530 if (TmpBB == LoadBB) // Infinite (unreachable) loop. 1531 return false; 1532 if (Blockers.count(TmpBB)) 1533 return false; 1534 if (TmpBB->getTerminator()->getNumSuccessors() != 1) 1535 allSingleSucc = false; 1536 } 1537 1538 assert(TmpBB); 1539 LoadBB = TmpBB; 1540 1541 // If we have a repl set with LI itself in it, this means we have a loop where 1542 // at least one of the values is LI. Since this means that we won't be able 1543 // to eliminate LI even if we insert uses in the other predecessors, we will 1544 // end up increasing code size. Reject this by scanning for LI. 1545 for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i) { 1546 if (ValuesPerBlock[i].isSimpleValue() && 1547 ValuesPerBlock[i].getSimpleValue() == LI) { 1548 // Skip cases where LI is the only definition, even for EnableFullLoadPRE. 1549 if (!EnableFullLoadPRE || e == 1) 1550 return false; 1551 } 1552 } 1553 1554 // FIXME: It is extremely unclear what this loop is doing, other than 1555 // artificially restricting loadpre. 1556 if (isSinglePred) { 1557 bool isHot = false; 1558 for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i) { 1559 const AvailableValueInBlock &AV = ValuesPerBlock[i]; 1560 if (AV.isSimpleValue()) 1561 // "Hot" Instruction is in some loop (because it dominates its dep. 1562 // instruction). 1563 if (Instruction *I = dyn_cast<Instruction>(AV.getSimpleValue())) 1564 if (DT->dominates(LI, I)) { 1565 isHot = true; 1566 break; 1567 } 1568 } 1569 1570 // We are interested only in "hot" instructions. We don't want to do any 1571 // mis-optimizations here. 1572 if (!isHot) 1573 return false; 1574 } 1575 1576 // Check to see how many predecessors have the loaded value fully 1577 // available. 1578 DenseMap<BasicBlock*, Value*> PredLoads; 1579 DenseMap<BasicBlock*, char> FullyAvailableBlocks; 1580 for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i) 1581 FullyAvailableBlocks[ValuesPerBlock[i].BB] = true; 1582 for (unsigned i = 0, e = UnavailableBlocks.size(); i != e; ++i) 1583 FullyAvailableBlocks[UnavailableBlocks[i]] = false; 1584 1585 bool NeedToSplitEdges = false; 1586 for (pred_iterator PI = pred_begin(LoadBB), E = pred_end(LoadBB); 1587 PI != E; ++PI) { 1588 BasicBlock *Pred = *PI; 1589 if (IsValueFullyAvailableInBlock(Pred, FullyAvailableBlocks)) { 1590 continue; 1591 } 1592 PredLoads[Pred] = 0; 1593 1594 if (Pred->getTerminator()->getNumSuccessors() != 1) { 1595 if (isa<IndirectBrInst>(Pred->getTerminator())) { 1596 DEBUG(dbgs() << "COULD NOT PRE LOAD BECAUSE OF INDBR CRITICAL EDGE '" 1597 << Pred->getName() << "': " << *LI << '\n'); 1598 return false; 1599 } 1600 unsigned SuccNum = GetSuccessorNumber(Pred, LoadBB); 1601 toSplit.push_back(std::make_pair(Pred->getTerminator(), SuccNum)); 1602 NeedToSplitEdges = true; 1603 } 1604 } 1605 if (NeedToSplitEdges) 1606 return false; 1607 1608 // Decide whether PRE is profitable for this load. 1609 unsigned NumUnavailablePreds = PredLoads.size(); 1610 assert(NumUnavailablePreds != 0 && 1611 "Fully available value should be eliminated above!"); 1612 if (!EnableFullLoadPRE) { 1613 // If this load is unavailable in multiple predecessors, reject it. 1614 // FIXME: If we could restructure the CFG, we could make a common pred with 1615 // all the preds that don't have an available LI and insert a new load into 1616 // that one block. 1617 if (NumUnavailablePreds != 1) 1618 return false; 1619 } 1620 1621 // Check if the load can safely be moved to all the unavailable predecessors. 1622 bool CanDoPRE = true; 1623 SmallVector<Instruction*, 8> NewInsts; 1624 for (DenseMap<BasicBlock*, Value*>::iterator I = PredLoads.begin(), 1625 E = PredLoads.end(); I != E; ++I) { 1626 BasicBlock *UnavailablePred = I->first; 1627 1628 // Do PHI translation to get its value in the predecessor if necessary. The 1629 // returned pointer (if non-null) is guaranteed to dominate UnavailablePred. 1630 1631 // If all preds have a single successor, then we know it is safe to insert 1632 // the load on the pred (?!?), so we can insert code to materialize the 1633 // pointer if it is not available. 1634 PHITransAddr Address(LI->getOperand(0), TD); 1635 Value *LoadPtr = 0; 1636 if (allSingleSucc) { 1637 LoadPtr = Address.PHITranslateWithInsertion(LoadBB, UnavailablePred, 1638 *DT, NewInsts); 1639 } else { 1640 Address.PHITranslateValue(LoadBB, UnavailablePred, DT); 1641 LoadPtr = Address.getAddr(); 1642 } 1643 1644 // If we couldn't find or insert a computation of this phi translated value, 1645 // we fail PRE. 1646 if (LoadPtr == 0) { 1647 DEBUG(dbgs() << "COULDN'T INSERT PHI TRANSLATED VALUE OF: " 1648 << *LI->getOperand(0) << "\n"); 1649 CanDoPRE = false; 1650 break; 1651 } 1652 1653 // Make sure it is valid to move this load here. We have to watch out for: 1654 // @1 = getelementptr (i8* p, ... 1655 // test p and branch if == 0 1656 // load @1 1657 // It is valid to have the getelementptr before the test, even if p can be 0, 1658 // as getelementptr only does address arithmetic. 1659 // If we are not pushing the value through any multiple-successor blocks 1660 // we do not have this case. Otherwise, check that the load is safe to 1661 // put anywhere; this can be improved, but should be conservatively safe. 1662 if (!allSingleSucc && 1663 // FIXME: REEVALUTE THIS. 1664 !isSafeToLoadUnconditionally(LoadPtr, 1665 UnavailablePred->getTerminator(), 1666 LI->getAlignment(), TD)) { 1667 CanDoPRE = false; 1668 break; 1669 } 1670 1671 I->second = LoadPtr; 1672 } 1673 1674 if (!CanDoPRE) { 1675 while (!NewInsts.empty()) 1676 NewInsts.pop_back_val()->eraseFromParent(); 1677 return false; 1678 } 1679 1680 // Okay, we can eliminate this load by inserting a reload in the predecessor 1681 // and using PHI construction to get the value in the other predecessors, do 1682 // it. 1683 DEBUG(dbgs() << "GVN REMOVING PRE LOAD: " << *LI << '\n'); 1684 DEBUG(if (!NewInsts.empty()) 1685 dbgs() << "INSERTED " << NewInsts.size() << " INSTS: " 1686 << *NewInsts.back() << '\n'); 1687 1688 // Assign value numbers to the new instructions. 1689 for (unsigned i = 0, e = NewInsts.size(); i != e; ++i) { 1690 // FIXME: We really _ought_ to insert these value numbers into their 1691 // parent's availability map. However, in doing so, we risk getting into 1692 // ordering issues. If a block hasn't been processed yet, we would be 1693 // marking a value as AVAIL-IN, which isn't what we intend. 1694 VN.lookup_or_add(NewInsts[i]); 1695 } 1696 1697 for (DenseMap<BasicBlock*, Value*>::iterator I = PredLoads.begin(), 1698 E = PredLoads.end(); I != E; ++I) { 1699 BasicBlock *UnavailablePred = I->first; 1700 Value *LoadPtr = I->second; 1701 1702 Value *NewLoad = new LoadInst(LoadPtr, LI->getName()+".pre", false, 1703 LI->getAlignment(), 1704 UnavailablePred->getTerminator()); 1705 1706 // Add the newly created load. 1707 ValuesPerBlock.push_back(AvailableValueInBlock::get(UnavailablePred, 1708 NewLoad)); 1709 MD->invalidateCachedPointerInfo(LoadPtr); 1710 DEBUG(dbgs() << "GVN INSERTED " << *NewLoad << '\n'); 1711 } 1712 1713 // Perform PHI construction. 1714 Value *V = ConstructSSAForLoadSet(LI, ValuesPerBlock, TD, *DT, 1715 VN.getAliasAnalysis()); 1716 LI->replaceAllUsesWith(V); 1717 if (isa<PHINode>(V)) 1718 V->takeName(LI); 1719 if (V->getType()->isPointerTy()) 1720 MD->invalidateCachedPointerInfo(V); 1721 VN.erase(LI); 1722 toErase.push_back(LI); 1723 NumPRELoad++; 1724 return true; 1725} 1726 1727/// processLoad - Attempt to eliminate a load, first by eliminating it 1728/// locally, and then attempting non-local elimination if that fails. 1729bool GVN::processLoad(LoadInst *L, SmallVectorImpl<Instruction*> &toErase) { 1730 if (!MD) 1731 return false; 1732 1733 if (L->isVolatile()) 1734 return false; 1735 1736 // ... to a pointer that has been loaded from before... 1737 MemDepResult Dep = MD->getDependency(L); 1738 1739 // If the value isn't available, don't do anything! 1740 if (Dep.isClobber()) { 1741 // Check to see if we have something like this: 1742 // store i32 123, i32* %P 1743 // %A = bitcast i32* %P to i8* 1744 // %B = gep i8* %A, i32 1 1745 // %C = load i8* %B 1746 // 1747 // We could do that by recognizing if the clobber instructions are obviously 1748 // a common base + constant offset, and if the previous store (or memset) 1749 // completely covers this load. This sort of thing can happen in bitfield 1750 // access code. 1751 Value *AvailVal = 0; 1752 if (StoreInst *DepSI = dyn_cast<StoreInst>(Dep.getInst())) 1753 if (const TargetData *TD = getAnalysisIfAvailable<TargetData>()) { 1754 int Offset = AnalyzeLoadFromClobberingStore(L->getType(), 1755 L->getPointerOperand(), 1756 DepSI, *TD); 1757 if (Offset != -1) 1758 AvailVal = GetStoreValueForLoad(DepSI->getOperand(0), Offset, 1759 L->getType(), L, *TD); 1760 } 1761 1762 // If the clobbering value is a memset/memcpy/memmove, see if we can forward 1763 // a value on from it. 1764 if (MemIntrinsic *DepMI = dyn_cast<MemIntrinsic>(Dep.getInst())) { 1765 if (const TargetData *TD = getAnalysisIfAvailable<TargetData>()) { 1766 int Offset = AnalyzeLoadFromClobberingMemInst(L->getType(), 1767 L->getPointerOperand(), 1768 DepMI, *TD); 1769 if (Offset != -1) 1770 AvailVal = GetMemInstValueForLoad(DepMI, Offset, L->getType(), L,*TD); 1771 } 1772 } 1773 1774 if (AvailVal) { 1775 DEBUG(dbgs() << "GVN COERCED INST:\n" << *Dep.getInst() << '\n' 1776 << *AvailVal << '\n' << *L << "\n\n\n"); 1777 1778 // Replace the load! 1779 L->replaceAllUsesWith(AvailVal); 1780 if (AvailVal->getType()->isPointerTy()) 1781 MD->invalidateCachedPointerInfo(AvailVal); 1782 VN.erase(L); 1783 toErase.push_back(L); 1784 NumGVNLoad++; 1785 return true; 1786 } 1787 1788 DEBUG( 1789 // fast print dep, using operator<< on instruction would be too slow 1790 dbgs() << "GVN: load "; 1791 WriteAsOperand(dbgs(), L); 1792 Instruction *I = Dep.getInst(); 1793 dbgs() << " is clobbered by " << *I << '\n'; 1794 ); 1795 return false; 1796 } 1797 1798 // If it is defined in another block, try harder. 1799 if (Dep.isNonLocal()) 1800 return processNonLocalLoad(L, toErase); 1801 1802 Instruction *DepInst = Dep.getInst(); 1803 if (StoreInst *DepSI = dyn_cast<StoreInst>(DepInst)) { 1804 Value *StoredVal = DepSI->getOperand(0); 1805 1806 // The store and load are to a must-aliased pointer, but they may not 1807 // actually have the same type. See if we know how to reuse the stored 1808 // value (depending on its type). 1809 const TargetData *TD = 0; 1810 if (StoredVal->getType() != L->getType()) { 1811 if ((TD = getAnalysisIfAvailable<TargetData>())) { 1812 StoredVal = CoerceAvailableValueToLoadType(StoredVal, L->getType(), 1813 L, *TD); 1814 if (StoredVal == 0) 1815 return false; 1816 1817 DEBUG(dbgs() << "GVN COERCED STORE:\n" << *DepSI << '\n' << *StoredVal 1818 << '\n' << *L << "\n\n\n"); 1819 } 1820 else 1821 return false; 1822 } 1823 1824 // Remove it! 1825 L->replaceAllUsesWith(StoredVal); 1826 if (StoredVal->getType()->isPointerTy()) 1827 MD->invalidateCachedPointerInfo(StoredVal); 1828 VN.erase(L); 1829 toErase.push_back(L); 1830 NumGVNLoad++; 1831 return true; 1832 } 1833 1834 if (LoadInst *DepLI = dyn_cast<LoadInst>(DepInst)) { 1835 Value *AvailableVal = DepLI; 1836 1837 // The loads are of a must-aliased pointer, but they may not actually have 1838 // the same type. See if we know how to reuse the previously loaded value 1839 // (depending on its type). 1840 const TargetData *TD = 0; 1841 if (DepLI->getType() != L->getType()) { 1842 if ((TD = getAnalysisIfAvailable<TargetData>())) { 1843 AvailableVal = CoerceAvailableValueToLoadType(DepLI, L->getType(), L,*TD); 1844 if (AvailableVal == 0) 1845 return false; 1846 1847 DEBUG(dbgs() << "GVN COERCED LOAD:\n" << *DepLI << "\n" << *AvailableVal 1848 << "\n" << *L << "\n\n\n"); 1849 } 1850 else 1851 return false; 1852 } 1853 1854 // Remove it! 1855 L->replaceAllUsesWith(AvailableVal); 1856 if (DepLI->getType()->isPointerTy()) 1857 MD->invalidateCachedPointerInfo(DepLI); 1858 VN.erase(L); 1859 toErase.push_back(L); 1860 NumGVNLoad++; 1861 return true; 1862 } 1863 1864 // If this load really doesn't depend on anything, then we must be loading an 1865 // undef value. This can happen when loading for a fresh allocation with no 1866 // intervening stores, for example. 1867 if (isa<AllocaInst>(DepInst) || isMalloc(DepInst)) { 1868 L->replaceAllUsesWith(UndefValue::get(L->getType())); 1869 VN.erase(L); 1870 toErase.push_back(L); 1871 NumGVNLoad++; 1872 return true; 1873 } 1874 1875 // If this load occurs either right after a lifetime begin, 1876 // then the loaded value is undefined. 1877 if (IntrinsicInst* II = dyn_cast<IntrinsicInst>(DepInst)) { 1878 if (II->getIntrinsicID() == Intrinsic::lifetime_start) { 1879 L->replaceAllUsesWith(UndefValue::get(L->getType())); 1880 VN.erase(L); 1881 toErase.push_back(L); 1882 NumGVNLoad++; 1883 return true; 1884 } 1885 } 1886 1887 return false; 1888} 1889 1890Value *GVN::lookupNumber(BasicBlock *BB, uint32_t num) { 1891 DenseMap<BasicBlock*, ValueNumberScope*>::iterator I = localAvail.find(BB); 1892 if (I == localAvail.end()) 1893 return 0; 1894 1895 ValueNumberScope *Locals = I->second; 1896 while (Locals) { 1897 DenseMap<uint32_t, Value*>::iterator I = Locals->table.find(num); 1898 if (I != Locals->table.end()) 1899 return I->second; 1900 Locals = Locals->parent; 1901 } 1902 1903 return 0; 1904} 1905 1906 1907/// processInstruction - When calculating availability, handle an instruction 1908/// by inserting it into the appropriate sets 1909bool GVN::processInstruction(Instruction *I, 1910 SmallVectorImpl<Instruction*> &toErase) { 1911 // Ignore dbg info intrinsics. 1912 if (isa<DbgInfoIntrinsic>(I)) 1913 return false; 1914 1915 if (LoadInst *LI = dyn_cast<LoadInst>(I)) { 1916 bool Changed = processLoad(LI, toErase); 1917 1918 if (!Changed) { 1919 unsigned Num = VN.lookup_or_add(LI); 1920 localAvail[I->getParent()]->table.insert(std::make_pair(Num, LI)); 1921 } 1922 1923 return Changed; 1924 } 1925 1926 uint32_t NextNum = VN.getNextUnusedValueNumber(); 1927 unsigned Num = VN.lookup_or_add(I); 1928 1929 if (BranchInst *BI = dyn_cast<BranchInst>(I)) { 1930 localAvail[I->getParent()]->table.insert(std::make_pair(Num, I)); 1931 1932 if (!BI->isConditional() || isa<Constant>(BI->getCondition())) 1933 return false; 1934 1935 Value *BranchCond = BI->getCondition(); 1936 uint32_t CondVN = VN.lookup_or_add(BranchCond); 1937 1938 BasicBlock *TrueSucc = BI->getSuccessor(0); 1939 BasicBlock *FalseSucc = BI->getSuccessor(1); 1940 1941 if (TrueSucc->getSinglePredecessor()) 1942 localAvail[TrueSucc]->table[CondVN] = 1943 ConstantInt::getTrue(TrueSucc->getContext()); 1944 if (FalseSucc->getSinglePredecessor()) 1945 localAvail[FalseSucc]->table[CondVN] = 1946 ConstantInt::getFalse(TrueSucc->getContext()); 1947 1948 return false; 1949 1950 // Allocations are always uniquely numbered, so we can save time and memory 1951 // by fast failing them. 1952 } else if (isa<AllocaInst>(I) || isa<TerminatorInst>(I)) { 1953 localAvail[I->getParent()]->table.insert(std::make_pair(Num, I)); 1954 return false; 1955 } 1956 1957 // Collapse PHI nodes 1958 if (PHINode* p = dyn_cast<PHINode>(I)) { 1959 Value *constVal = CollapsePhi(p); 1960 1961 if (constVal) { 1962 p->replaceAllUsesWith(constVal); 1963 if (MD && constVal->getType()->isPointerTy()) 1964 MD->invalidateCachedPointerInfo(constVal); 1965 VN.erase(p); 1966 1967 toErase.push_back(p); 1968 } else { 1969 localAvail[I->getParent()]->table.insert(std::make_pair(Num, I)); 1970 } 1971 1972 // If the number we were assigned was a brand new VN, then we don't 1973 // need to do a lookup to see if the number already exists 1974 // somewhere in the domtree: it can't! 1975 } else if (Num == NextNum) { 1976 localAvail[I->getParent()]->table.insert(std::make_pair(Num, I)); 1977 1978 // Perform fast-path value-number based elimination of values inherited from 1979 // dominators. 1980 } else if (Value *repl = lookupNumber(I->getParent(), Num)) { 1981 // Remove it! 1982 VN.erase(I); 1983 I->replaceAllUsesWith(repl); 1984 if (MD && repl->getType()->isPointerTy()) 1985 MD->invalidateCachedPointerInfo(repl); 1986 toErase.push_back(I); 1987 return true; 1988 1989 } else { 1990 localAvail[I->getParent()]->table.insert(std::make_pair(Num, I)); 1991 } 1992 1993 return false; 1994} 1995 1996/// runOnFunction - This is the main transformation entry point for a function. 1997bool GVN::runOnFunction(Function& F) { 1998 if (!NoLoads) 1999 MD = &getAnalysis<MemoryDependenceAnalysis>(); 2000 DT = &getAnalysis<DominatorTree>(); 2001 VN.setAliasAnalysis(&getAnalysis<AliasAnalysis>()); 2002 VN.setMemDep(MD); 2003 VN.setDomTree(DT); 2004 2005 bool Changed = false; 2006 bool ShouldContinue = true; 2007 2008 // Merge unconditional branches, allowing PRE to catch more 2009 // optimization opportunities. 2010 for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ) { 2011 BasicBlock *BB = FI; 2012 ++FI; 2013 bool removedBlock = MergeBlockIntoPredecessor(BB, this); 2014 if (removedBlock) NumGVNBlocks++; 2015 2016 Changed |= removedBlock; 2017 } 2018 2019 unsigned Iteration = 0; 2020 2021 while (ShouldContinue) { 2022 DEBUG(dbgs() << "GVN iteration: " << Iteration << "\n"); 2023 ShouldContinue = iterateOnFunction(F); 2024 if (splitCriticalEdges()) 2025 ShouldContinue = true; 2026 Changed |= ShouldContinue; 2027 ++Iteration; 2028 } 2029 2030 if (EnablePRE) { 2031 bool PREChanged = true; 2032 while (PREChanged) { 2033 PREChanged = performPRE(F); 2034 Changed |= PREChanged; 2035 } 2036 } 2037 // FIXME: Should perform GVN again after PRE does something. PRE can move 2038 // computations into blocks where they become fully redundant. Note that 2039 // we can't do this until PRE's critical edge splitting updates memdep. 2040 // Actually, when this happens, we should just fully integrate PRE into GVN. 2041 2042 cleanupGlobalSets(); 2043 2044 return Changed; 2045} 2046 2047 2048bool GVN::processBlock(BasicBlock *BB) { 2049 // FIXME: Kill off toErase by doing erasing eagerly in a helper function (and 2050 // incrementing BI before processing an instruction). 2051 SmallVector<Instruction*, 8> toErase; 2052 bool ChangedFunction = false; 2053 2054 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); 2055 BI != BE;) { 2056 ChangedFunction |= processInstruction(BI, toErase); 2057 if (toErase.empty()) { 2058 ++BI; 2059 continue; 2060 } 2061 2062 // If we need some instructions deleted, do it now. 2063 NumGVNInstr += toErase.size(); 2064 2065 // Avoid iterator invalidation. 2066 bool AtStart = BI == BB->begin(); 2067 if (!AtStart) 2068 --BI; 2069 2070 for (SmallVector<Instruction*, 4>::iterator I = toErase.begin(), 2071 E = toErase.end(); I != E; ++I) { 2072 DEBUG(dbgs() << "GVN removed: " << **I << '\n'); 2073 if (MD) MD->removeInstruction(*I); 2074 (*I)->eraseFromParent(); 2075 DEBUG(verifyRemoved(*I)); 2076 } 2077 toErase.clear(); 2078 2079 if (AtStart) 2080 BI = BB->begin(); 2081 else 2082 ++BI; 2083 } 2084 2085 return ChangedFunction; 2086} 2087 2088/// performPRE - Perform a purely local form of PRE that looks for diamond 2089/// control flow patterns and attempts to perform simple PRE at the join point. 2090bool GVN::performPRE(Function &F) { 2091 bool Changed = false; 2092 DenseMap<BasicBlock*, Value*> predMap; 2093 for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()), 2094 DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) { 2095 BasicBlock *CurrentBlock = *DI; 2096 2097 // Nothing to PRE in the entry block. 2098 if (CurrentBlock == &F.getEntryBlock()) continue; 2099 2100 for (BasicBlock::iterator BI = CurrentBlock->begin(), 2101 BE = CurrentBlock->end(); BI != BE; ) { 2102 Instruction *CurInst = BI++; 2103 2104 if (isa<AllocaInst>(CurInst) || 2105 isa<TerminatorInst>(CurInst) || isa<PHINode>(CurInst) || 2106 CurInst->getType()->isVoidTy() || 2107 CurInst->mayReadFromMemory() || CurInst->mayHaveSideEffects() || 2108 isa<DbgInfoIntrinsic>(CurInst)) 2109 continue; 2110 2111 uint32_t ValNo = VN.lookup(CurInst); 2112 2113 // Look for the predecessors for PRE opportunities. We're 2114 // only trying to solve the basic diamond case, where 2115 // a value is computed in the successor and one predecessor, 2116 // but not the other. We also explicitly disallow cases 2117 // where the successor is its own predecessor, because they're 2118 // more complicated to get right. 2119 unsigned NumWith = 0; 2120 unsigned NumWithout = 0; 2121 BasicBlock *PREPred = 0; 2122 predMap.clear(); 2123 2124 for (pred_iterator PI = pred_begin(CurrentBlock), 2125 PE = pred_end(CurrentBlock); PI != PE; ++PI) { 2126 // We're not interested in PRE where the block is its 2127 // own predecessor, or in blocks with predecessors 2128 // that are not reachable. 2129 if (*PI == CurrentBlock) { 2130 NumWithout = 2; 2131 break; 2132 } else if (!localAvail.count(*PI)) { 2133 NumWithout = 2; 2134 break; 2135 } 2136 2137 DenseMap<uint32_t, Value*>::iterator predV = 2138 localAvail[*PI]->table.find(ValNo); 2139 if (predV == localAvail[*PI]->table.end()) { 2140 PREPred = *PI; 2141 NumWithout++; 2142 } else if (predV->second == CurInst) { 2143 NumWithout = 2; 2144 } else { 2145 predMap[*PI] = predV->second; 2146 NumWith++; 2147 } 2148 } 2149 2150 // Don't do PRE when it might increase code size, i.e. when 2151 // we would need to insert instructions in more than one pred. 2152 if (NumWithout != 1 || NumWith == 0) 2153 continue; 2154 2155 // Don't do PRE across indirect branch. 2156 if (isa<IndirectBrInst>(PREPred->getTerminator())) 2157 continue; 2158 2159 // We can't do PRE safely on a critical edge, so instead we schedule 2160 // the edge to be split and perform the PRE the next time we iterate 2161 // on the function. 2162 unsigned SuccNum = GetSuccessorNumber(PREPred, CurrentBlock); 2163 if (isCriticalEdge(PREPred->getTerminator(), SuccNum)) { 2164 toSplit.push_back(std::make_pair(PREPred->getTerminator(), SuccNum)); 2165 continue; 2166 } 2167 2168 // Instantiate the expression in the predecessor that lacked it. 2169 // Because we are going top-down through the block, all value numbers 2170 // will be available in the predecessor by the time we need them. Any 2171 // that weren't originally present will have been instantiated earlier 2172 // in this loop. 2173 Instruction *PREInstr = CurInst->clone(); 2174 bool success = true; 2175 for (unsigned i = 0, e = CurInst->getNumOperands(); i != e; ++i) { 2176 Value *Op = PREInstr->getOperand(i); 2177 if (isa<Argument>(Op) || isa<Constant>(Op) || isa<GlobalValue>(Op)) 2178 continue; 2179 2180 if (Value *V = lookupNumber(PREPred, VN.lookup(Op))) { 2181 PREInstr->setOperand(i, V); 2182 } else { 2183 success = false; 2184 break; 2185 } 2186 } 2187 2188 // Fail out if we encounter an operand that is not available in 2189 // the PRE predecessor. This is typically because of loads which 2190 // are not value numbered precisely. 2191 if (!success) { 2192 delete PREInstr; 2193 DEBUG(verifyRemoved(PREInstr)); 2194 continue; 2195 } 2196 2197 PREInstr->insertBefore(PREPred->getTerminator()); 2198 PREInstr->setName(CurInst->getName() + ".pre"); 2199 predMap[PREPred] = PREInstr; 2200 VN.add(PREInstr, ValNo); 2201 NumGVNPRE++; 2202 2203 // Update the availability map to include the new instruction. 2204 localAvail[PREPred]->table.insert(std::make_pair(ValNo, PREInstr)); 2205 2206 // Create a PHI to make the value available in this block. 2207 PHINode* Phi = PHINode::Create(CurInst->getType(), 2208 CurInst->getName() + ".pre-phi", 2209 CurrentBlock->begin()); 2210 for (pred_iterator PI = pred_begin(CurrentBlock), 2211 PE = pred_end(CurrentBlock); PI != PE; ++PI) 2212 Phi->addIncoming(predMap[*PI], *PI); 2213 2214 VN.add(Phi, ValNo); 2215 localAvail[CurrentBlock]->table[ValNo] = Phi; 2216 2217 CurInst->replaceAllUsesWith(Phi); 2218 if (MD && Phi->getType()->isPointerTy()) 2219 MD->invalidateCachedPointerInfo(Phi); 2220 VN.erase(CurInst); 2221 2222 DEBUG(dbgs() << "GVN PRE removed: " << *CurInst << '\n'); 2223 if (MD) MD->removeInstruction(CurInst); 2224 CurInst->eraseFromParent(); 2225 DEBUG(verifyRemoved(CurInst)); 2226 Changed = true; 2227 } 2228 } 2229 2230 if (splitCriticalEdges()) 2231 Changed = true; 2232 2233 return Changed; 2234} 2235 2236/// splitCriticalEdges - Split critical edges found during the previous 2237/// iteration that may enable further optimization. 2238bool GVN::splitCriticalEdges() { 2239 if (toSplit.empty()) 2240 return false; 2241 do { 2242 std::pair<TerminatorInst*, unsigned> Edge = toSplit.pop_back_val(); 2243 SplitCriticalEdge(Edge.first, Edge.second, this); 2244 } while (!toSplit.empty()); 2245 if (MD) MD->invalidateCachedPredecessors(); 2246 return true; 2247} 2248 2249/// iterateOnFunction - Executes one iteration of GVN 2250bool GVN::iterateOnFunction(Function &F) { 2251 cleanupGlobalSets(); 2252 2253 for (df_iterator<DomTreeNode*> DI = df_begin(DT->getRootNode()), 2254 DE = df_end(DT->getRootNode()); DI != DE; ++DI) { 2255 if (DI->getIDom()) 2256 localAvail[DI->getBlock()] = 2257 new ValueNumberScope(localAvail[DI->getIDom()->getBlock()]); 2258 else 2259 localAvail[DI->getBlock()] = new ValueNumberScope(0); 2260 } 2261 2262 // Top-down walk of the dominator tree 2263 bool Changed = false; 2264#if 0 2265 // Needed for value numbering with phi construction to work. 2266 ReversePostOrderTraversal<Function*> RPOT(&F); 2267 for (ReversePostOrderTraversal<Function*>::rpo_iterator RI = RPOT.begin(), 2268 RE = RPOT.end(); RI != RE; ++RI) 2269 Changed |= processBlock(*RI); 2270#else 2271 for (df_iterator<DomTreeNode*> DI = df_begin(DT->getRootNode()), 2272 DE = df_end(DT->getRootNode()); DI != DE; ++DI) 2273 Changed |= processBlock(DI->getBlock()); 2274#endif 2275 2276 return Changed; 2277} 2278 2279void GVN::cleanupGlobalSets() { 2280 VN.clear(); 2281 2282 for (DenseMap<BasicBlock*, ValueNumberScope*>::iterator 2283 I = localAvail.begin(), E = localAvail.end(); I != E; ++I) 2284 delete I->second; 2285 localAvail.clear(); 2286} 2287 2288/// verifyRemoved - Verify that the specified instruction does not occur in our 2289/// internal data structures. 2290void GVN::verifyRemoved(const Instruction *Inst) const { 2291 VN.verifyRemoved(Inst); 2292 2293 // Walk through the value number scope to make sure the instruction isn't 2294 // ferreted away in it. 2295 for (DenseMap<BasicBlock*, ValueNumberScope*>::const_iterator 2296 I = localAvail.begin(), E = localAvail.end(); I != E; ++I) { 2297 const ValueNumberScope *VNS = I->second; 2298 2299 while (VNS) { 2300 for (DenseMap<uint32_t, Value*>::const_iterator 2301 II = VNS->table.begin(), IE = VNS->table.end(); II != IE; ++II) { 2302 assert(II->second != Inst && "Inst still in value numbering scope!"); 2303 } 2304 2305 VNS = VNS->parent; 2306 } 2307 } 2308} 2309