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Don't insert nearly as many redundant phi nodes.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40909 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2007-08-07 23:12:31 +00:00
parent 84109cd015
commit a37226af81
1 changed files with 25 additions and 2 deletions
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27
lib/Transforms/Scalar/GVN.cpp
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@ -642,6 +642,10 @@ namespace {
DenseMap<BasicBlock*, ValueNumberedSet> availableOut;
typedef DenseMap<Value*, SmallPtrSet<Instruction*, 4> > PhiMapType;
PhiMapType phiMap;
// This transformation requires dominator postdominator info
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
@ -780,6 +784,7 @@ Value *GVN::GetValueForBlock(BasicBlock *BB, LoadInst* orig,
return first;
}
phiMap[orig->getPointerOperand()].insert(PN);
return PN;
}
@ -791,6 +796,7 @@ bool GVN::processNonLocalLoad(LoadInst* L,
MD.getNonLocalDependency(L, deps);
DenseMap<BasicBlock*, Value*> repl;
for (DenseMap<BasicBlock*, Value*>::iterator I = deps.begin(), E = deps.end();
I != E; ++I)
if (I->second == MemoryDependenceAnalysis::None) {
@ -799,24 +805,40 @@ bool GVN::processNonLocalLoad(LoadInst* L,
continue;
}else if (StoreInst* S = dyn_cast<StoreInst>(I->second)) {
if (S->getPointerOperand() == L->getPointerOperand())
repl.insert(std::make_pair(I->first, S->getOperand(0)));
repl[I->first] = S->getOperand(0);
else
return false;
} else if (LoadInst* LD = dyn_cast<LoadInst>(I->second)) {
if (LD->getPointerOperand() == L->getPointerOperand())
repl.insert(std::make_pair(I->first, LD));
repl[I->first] = LD;
else
return false;
} else {
return false;
}
SmallPtrSet<Instruction*, 4>& p = phiMap[L->getPointerOperand()];
for (SmallPtrSet<Instruction*, 4>::iterator I = p.begin(), E = p.end();
I != E; ++I) {
if ((*I)->getParent() == L->getParent()) {
MD.removeInstruction(L);
L->replaceAllUsesWith(*I);
toErase.push_back(L);
NumGVNLoad++;
return true;
} else {
repl.insert(std::make_pair((*I)->getParent(), *I));
}
}
SmallPtrSet<BasicBlock*, 4> visited;
Value* v = GetValueForBlock(L->getParent(), L, repl, true);
MD.removeInstruction(L);
L->replaceAllUsesWith(v);
toErase.push_back(L);
NumGVNLoad++;
return true;
}
@ -917,6 +939,7 @@ bool GVN::runOnFunction(Function &F) {
// Clean out global sets from any previous functions
VN.clear();
availableOut.clear();
phiMap.clear();
bool changed_function = false;