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Implement test/Regression/Transforms/GCSE/undefined_load.ll 

llvm-svn: 12641
This commit is contained in:
Chris Lattner 2004-04-03 00:45:16 +00:00
parent db033fa425
commit 8ed3c8aa13
1 changed files with 14 additions and 0 deletions
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14
llvm/lib/Analysis/LoadValueNumbering.cpp
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@ -22,6 +22,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/LoadValueNumbering.h"
#include "llvm/Constant.h"
#include "llvm/Function.h"
#include "llvm/iMemory.h"
#include "llvm/iOther.h"
@ -283,10 +284,14 @@ void LoadVN::getEqualNumberNodes(Value *V,
//
std::map<BasicBlock*, std::vector<LoadInst*> > CandidateLoads;
std::map<BasicBlock*, std::vector<StoreInst*> > CandidateStores;
std::set<AllocationInst*> Allocations;
while (!PointerSources.empty()) {
Value *Source = PointerSources.back();
PointerSources.pop_back(); // Get a source pointer...
if (AllocationInst *AI = dyn_cast<AllocationInst>(Source))
Allocations.insert(AI);
for (Value::use_iterator UI = Source->use_begin(), UE = Source->use_end();
UI != UE; ++UI)
@ -329,6 +334,15 @@ void LoadVN::getEqualNumberNodes(Value *V,
if (isa<LoadInst>(I) && Instrs.count(I)) {
RetVals.push_back(I);
Instrs.erase(I);
} else if (AllocationInst *AI = dyn_cast<AllocationInst>(I)) {
// If we run into an allocation of the value being loaded, then the
// contenxt are not initialized. We can return any value, so we will
// return a zero.
if (Allocations.count(AI)) {
LoadInvalidatedInBBBefore = true;
RetVals.push_back(Constant::getNullValue(LI->getType()));
break;
}
}
if (AA.getModRefInfo(I, LoadPtr, LoadSize) & AliasAnalysis::Mod) {