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https://github.com/c64scene-ar/llvm-6502.git
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Allow GVN to eliminate redundant calls to functions without side effects.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43147 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson
parent
c5ccbdbe32
commit
b388ca9544
@ -21,13 +21,14 @@
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#include "llvm/Function.h"
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#include "llvm/Instructions.h"
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#include "llvm/Value.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/ADT/BitVector.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Analysis/MemoryDependenceAnalysis.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/Support/Compiler.h"
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@ -51,7 +52,7 @@ namespace {
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FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT,
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SHUFFLE, SELECT, TRUNC, ZEXT, SEXT, FPTOUI,
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FPTOSI, UITOFP, SITOFP, FPTRUNC, FPEXT,
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PTRTOINT, INTTOPTR, BITCAST, GEP, EMPTY,
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PTRTOINT, INTTOPTR, BITCAST, GEP, CALL, EMPTY,
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TOMBSTONE };
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ExpressionOpcode opcode;
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@ -60,6 +61,7 @@ namespace {
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uint32_t secondVN;
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uint32_t thirdVN;
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SmallVector<uint32_t, 4> varargs;
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Value* function;
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Expression() { }
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Expression(ExpressionOpcode o) : opcode(o) { }
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@ -71,6 +73,8 @@ namespace {
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return true;
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else if (type != other.type)
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return false;
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else if (function != other.function)
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return false;
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else if (firstVN != other.firstVN)
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return false;
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else if (secondVN != other.secondVN)
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@ -96,6 +100,8 @@ namespace {
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return false;
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else if (type != other.type)
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return true;
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else if (function != other.function)
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return true;
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else if (firstVN != other.firstVN)
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return true;
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else if (secondVN != other.secondVN)
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@ -119,6 +125,7 @@ namespace {
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private:
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DenseMap<Value*, uint32_t> valueNumbering;
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DenseMap<Expression, uint32_t> expressionNumbering;
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AliasAnalysis* AA;
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uint32_t nextValueNumber;
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@ -133,14 +140,16 @@ namespace {
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Expression create_expression(SelectInst* V);
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Expression create_expression(CastInst* C);
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Expression create_expression(GetElementPtrInst* G);
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Expression create_expression(CallInst* C);
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public:
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ValueTable() { nextValueNumber = 1; }
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ValueTable() : nextValueNumber(1) { }
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uint32_t lookup_or_add(Value* V);
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uint32_t lookup(Value* V) const;
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void add(Value* V, uint32_t num);
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void clear();
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void erase(Value* v);
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unsigned size();
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void setAliasAnalysis(AliasAnalysis* A) { AA = A; }
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};
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}
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@ -169,6 +178,10 @@ template <> struct DenseMapInfo<Expression> {
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E = e.varargs.end(); I != E; ++I)
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hash = *I + hash * 37;
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hash = (unsigned)((uintptr_t)e.function >> 4) ^
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(unsigned)((uintptr_t)e.function >> 9) +
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hash * 37;
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return hash;
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}
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static bool isEqual(const Expression &LHS, const Expression &RHS) {
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@ -325,12 +338,30 @@ Expression::ExpressionOpcode
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}
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}
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Expression ValueTable::create_expression(CallInst* C) {
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Expression e;
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e.type = C->getType();
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e.firstVN = 0;
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e.secondVN = 0;
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e.thirdVN = 0;
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e.function = C->getCalledFunction();
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e.opcode = Expression::CALL;
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for (CallInst::op_iterator I = C->op_begin()+1, E = C->op_end();
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I != E; ++I)
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e.varargs.push_back(lookup_or_add(*I));
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return e;
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}
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Expression ValueTable::create_expression(BinaryOperator* BO) {
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Expression e;
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e.firstVN = lookup_or_add(BO->getOperand(0));
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e.secondVN = lookup_or_add(BO->getOperand(1));
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e.thirdVN = 0;
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e.function = 0;
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e.type = BO->getType();
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e.opcode = getOpcode(BO);
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@ -343,6 +374,7 @@ Expression ValueTable::create_expression(CmpInst* C) {
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e.firstVN = lookup_or_add(C->getOperand(0));
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e.secondVN = lookup_or_add(C->getOperand(1));
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e.thirdVN = 0;
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e.function = 0;
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e.type = C->getType();
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e.opcode = getOpcode(C);
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@ -355,6 +387,7 @@ Expression ValueTable::create_expression(CastInst* C) {
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e.firstVN = lookup_or_add(C->getOperand(0));
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e.secondVN = 0;
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e.thirdVN = 0;
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e.function = 0;
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e.type = C->getType();
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e.opcode = getOpcode(C);
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@ -367,6 +400,7 @@ Expression ValueTable::create_expression(ShuffleVectorInst* S) {
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e.firstVN = lookup_or_add(S->getOperand(0));
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e.secondVN = lookup_or_add(S->getOperand(1));
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e.thirdVN = lookup_or_add(S->getOperand(2));
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e.function = 0;
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e.type = S->getType();
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e.opcode = Expression::SHUFFLE;
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@ -379,6 +413,7 @@ Expression ValueTable::create_expression(ExtractElementInst* E) {
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e.firstVN = lookup_or_add(E->getOperand(0));
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e.secondVN = lookup_or_add(E->getOperand(1));
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e.thirdVN = 0;
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e.function = 0;
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e.type = E->getType();
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e.opcode = Expression::EXTRACT;
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@ -391,6 +426,7 @@ Expression ValueTable::create_expression(InsertElementInst* I) {
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e.firstVN = lookup_or_add(I->getOperand(0));
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e.secondVN = lookup_or_add(I->getOperand(1));
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e.thirdVN = lookup_or_add(I->getOperand(2));
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e.function = 0;
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e.type = I->getType();
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e.opcode = Expression::INSERT;
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@ -403,6 +439,7 @@ Expression ValueTable::create_expression(SelectInst* I) {
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e.firstVN = lookup_or_add(I->getCondition());
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e.secondVN = lookup_or_add(I->getTrueValue());
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e.thirdVN = lookup_or_add(I->getFalseValue());
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e.function = 0;
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e.type = I->getType();
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e.opcode = Expression::SELECT;
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@ -415,6 +452,7 @@ Expression ValueTable::create_expression(GetElementPtrInst* G) {
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e.firstVN = lookup_or_add(G->getPointerOperand());
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e.secondVN = 0;
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e.thirdVN = 0;
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e.function = 0;
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e.type = G->getType();
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e.opcode = Expression::GEP;
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@ -436,8 +474,26 @@ uint32_t ValueTable::lookup_or_add(Value* V) {
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if (VI != valueNumbering.end())
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return VI->second;
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if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
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if (CallInst* C = dyn_cast<CallInst>(V)) {
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if (C->getCalledFunction() &&
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AA->doesNotAccessMemory(C->getCalledFunction())) {
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Expression e = create_expression(C);
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DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
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if (EI != expressionNumbering.end()) {
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valueNumbering.insert(std::make_pair(V, EI->second));
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return EI->second;
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} else {
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expressionNumbering.insert(std::make_pair(e, nextValueNumber));
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valueNumbering.insert(std::make_pair(V, nextValueNumber));
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return nextValueNumber++;
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}
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} else {
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valueNumbering.insert(std::make_pair(V, nextValueNumber));
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return nextValueNumber++;
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}
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} else if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
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Expression e = create_expression(BO);
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DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
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@ -654,6 +710,8 @@ namespace {
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AU.setPreservesCFG();
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AU.addRequired<DominatorTree>();
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AU.addRequired<MemoryDependenceAnalysis>();
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AU.addRequired<AliasAnalysis>();
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AU.addPreserved<AliasAnalysis>();
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AU.addPreserved<MemoryDependenceAnalysis>();
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}
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@ -996,6 +1054,8 @@ bool GVN::processInstruction(Instruction* I,
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// function.
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//
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bool GVN::runOnFunction(Function& F) {
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VN.setAliasAnalysis(&getAnalysis<AliasAnalysis>());
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bool changed = false;
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bool shouldContinue = true;
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