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Fix PR4882, by making MemCpyOpt not dereference removed stores to get the

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context for the newly created operations.
 
Patch by Jakub Staszak!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81175 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2009-09-08 00:27:14 +00:00
parent b9a4ddbbcd
commit ff1e98c72a
2 changed files with 56 additions and 12 deletions
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23
lib/Transforms/Scalar/MemCpyOptimizer.cpp
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@@ -340,13 +340,15 @@ static RegisterPass<MemCpyOpt> X("memcpyopt",
bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
if (SI->isVolatile()) return false;
LLVMContext &Context = SI->getContext();
// There are two cases that are interesting for this code to handle: memcpy
// and memset. Right now we only handle memset.
// Ensure that the value being stored is something that can be memset'able a
// byte at a time like "0" or "-1" or any width, as well as things like
// 0xA0A0A0A0 and 0.0.
Value *ByteVal = isBytewiseValue(SI->getOperand(0), SI->getContext());
Value *ByteVal = isBytewiseValue(SI->getOperand(0), Context);
if (!ByteVal)
return false;
@@ -387,8 +389,7 @@ bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
if (NextStore->isVolatile()) break;
// Check to see if this stored value is of the same byte-splattable value.
if (ByteVal != isBytewiseValue(NextStore->getOperand(0),
NextStore->getContext()))
if (ByteVal != isBytewiseValue(NextStore->getOperand(0), Context))
break;
// Check to see if this store is to a constant offset from the start ptr.
@@ -408,7 +409,6 @@ bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
// store as well. We try to avoid this unless there is at least something
// interesting as a small compile-time optimization.
Ranges.addStore(0, SI);
Function *MemSetF = 0;
@@ -432,16 +432,15 @@ bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
BasicBlock::iterator InsertPt = BI;
if (MemSetF == 0) {
const Type *Ty = Type::getInt64Ty(SI->getContext());
const Type *Ty = Type::getInt64Ty(Context);
MemSetF = Intrinsic::getDeclaration(M, Intrinsic::memset, &Ty, 1);
}
}
// Get the starting pointer of the block.
StartPtr = Range.StartPtr;
// Cast the start ptr to be i8* as memset requires.
const Type *i8Ptr =
PointerType::getUnqual(Type::getInt8Ty(SI->getContext()));
const Type *i8Ptr = PointerType::getUnqual(Type::getInt8Ty(Context));
if (StartPtr->getType() != i8Ptr)
StartPtr = new BitCastInst(StartPtr, i8Ptr, StartPtr->getName(),
InsertPt);
@@ -449,10 +448,9 @@ bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
Value *Ops[] = {
StartPtr, ByteVal, // Start, value
// size
ConstantInt::get(Type::getInt64Ty(SI->getContext()),
Range.End-Range.Start),
ConstantInt::get(Type::getInt64Ty(Context), Range.End-Range.Start),
// align
ConstantInt::get(Type::getInt32Ty(SI->getContext()), Range.Alignment)
ConstantInt::get(Type::getInt32Ty(Context), Range.Alignment)
};
Value *C = CallInst::Create(MemSetF, Ops, Ops+4, "", InsertPt);
DEBUG(errs() << "Replace stores:\n";
@@ -464,7 +462,8 @@ bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
BBI = BI;
// Zap all the stores.
for (SmallVector<StoreInst*, 16>::const_iterator SI = Range.TheStores.begin(),
for (SmallVector<StoreInst*, 16>::const_iterator
SI = Range.TheStores.begin(),
SE = Range.TheStores.end(); SI != SE; ++SI)
(*SI)->eraseFromParent();
++NumMemSetInfer;