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Generalize LoadAndStorePromoter a bit and switch LICM

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to use it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123501 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2011-01-15 00:12:35 +00:00
parent ca3f06963c
commit deaf55f698
4 changed files with 131 additions and 193 deletions
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41
lib/Transforms/Utils/SSAUpdater.cpp
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@ -348,23 +348,25 @@ Value *SSAUpdater::GetValueAtEndOfBlockInternal(BasicBlock *BB) {
// LoadAndStorePromoter Implementation
//===----------------------------------------------------------------------===//
void LoadAndStorePromoter::run(StringRef BaseName,
const SmallVectorImpl<Instruction*> &Insts,
SSAUpdater *SSA) {
LoadAndStorePromoter::
LoadAndStorePromoter(const SmallVectorImpl<Instruction*> &Insts,
SSAUpdater &S, StringRef BaseName) : SSA(S) {
if (Insts.empty()) return;
// If no SSAUpdater was provided, use a default one. This allows the client
// to capture inserted PHI nodes etc if they want.
SSAUpdater DefaultSSA;
if (SSA == 0) SSA = &DefaultSSA;
const Type *ValTy;
Value *SomeVal;
if (LoadInst *LI = dyn_cast<LoadInst>(Insts[0]))
ValTy = LI->getType();
SomeVal = LI;
else
ValTy = cast<StoreInst>(Insts[0])->getOperand(0)->getType();
SSA->Initialize(ValTy, BaseName);
SomeVal = cast<StoreInst>(Insts[0])->getOperand(0);
if (BaseName.empty())
BaseName = SomeVal->getName();
SSA.Initialize(SomeVal->getType(), BaseName);
}
void LoadAndStorePromoter::
run(const SmallVectorImpl<Instruction*> &Insts) const {
// First step: bucket up uses of the alloca by the block they occur in.
// This is important because we have to handle multiple defs/uses in a block
@ -396,7 +398,7 @@ void LoadAndStorePromoter::run(StringRef BaseName,
if (BlockUses.size() == 1) {
// If it is a store, it is a trivial def of the value in the block.
if (StoreInst *SI = dyn_cast<StoreInst>(User))
SSA->AddAvailableValue(BB, SI->getOperand(0));
SSA.AddAvailableValue(BB, SI->getOperand(0));
else
// Otherwise it is a load, queue it to rewrite as a live-in load.
LiveInLoads.push_back(cast<LoadInst>(User));
@ -437,6 +439,7 @@ void LoadAndStorePromoter::run(StringRef BaseName,
// If we haven't seen a store yet, this is a live in use, otherwise
// use the stored value.
if (StoredValue) {
replaceLoadWithValue(L, StoredValue);
L->replaceAllUsesWith(StoredValue);
ReplacedLoads[L] = StoredValue;
} else {
@ -456,7 +459,7 @@ void LoadAndStorePromoter::run(StringRef BaseName,
// The last stored value that happened is the live-out for the block.
assert(StoredValue && "Already checked that there is a store in block");
SSA->AddAvailableValue(BB, StoredValue);
SSA.AddAvailableValue(BB, StoredValue);
BlockUses.clear();
}
@ -464,11 +467,15 @@ void LoadAndStorePromoter::run(StringRef BaseName,
// inserting PHI nodes as necessary.
for (unsigned i = 0, e = LiveInLoads.size(); i != e; ++i) {
LoadInst *ALoad = LiveInLoads[i];
Value *NewVal = SSA->GetValueInMiddleOfBlock(ALoad->getParent());
Value *NewVal = SSA.GetValueInMiddleOfBlock(ALoad->getParent());
replaceLoadWithValue(ALoad, NewVal);
ALoad->replaceAllUsesWith(NewVal);
ReplacedLoads[ALoad] = NewVal;
}
// Allow the client to do stuff before we start nuking things.
doExtraRewritesBeforeFinalDeletion();
// Now that everything is rewritten, delete the old instructions from the
// function. They should all be dead now.
for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
@ -491,9 +498,11 @@ void LoadAndStorePromoter::run(StringRef BaseName,
RLI = ReplacedLoads.find(NewVal);
}
replaceLoadWithValue(cast<LoadInst>(User), NewVal);
User->replaceAllUsesWith(NewVal);
}
instructionDeleted(User);
User->eraseFromParent();
}
}