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factor memcpy/memmove simplification out to its own SimplifyMemTransfer

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method, no functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45944 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-01-13 23:50:23 +00:00
parent 88b39744ec
commit f497b028b8
1 changed files with 42 additions and 35 deletions
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77
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -366,6 +366,8 @@ namespace {
Instruction *PromoteCastOfAllocation(BitCastInst &CI, AllocationInst &AI);
Instruction *MatchBSwap(BinaryOperator &I);
bool SimplifyStoreAtEndOfBlock(StoreInst &SI);
Instruction *SimplifyMemTransfer(MemIntrinsic *MI);
Value *EvaluateInDifferentType(Value *V, const Type *Ty, bool isSigned);
};
@ -7808,6 +7810,43 @@ static unsigned GetOrEnforceKnownAlignment(Value *V, TargetData *TD,
return 0;
}
Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) {
unsigned DstAlign = GetOrEnforceKnownAlignment(MI->getOperand(1), TD);
unsigned SrcAlign = GetOrEnforceKnownAlignment(MI->getOperand(2), TD);
unsigned MinAlign = std::min(DstAlign, SrcAlign);
unsigned CopyAlign = MI->getAlignment()->getZExtValue();
if (CopyAlign < MinAlign) {
MI->setAlignment(ConstantInt::get(Type::Int32Ty, MinAlign));
return MI;
}
// If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with
// load/store.
ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getOperand(3));
if (MemOpLength == 0) return 0;
// Source and destination pointer types are always "i8*" for intrinsic.
// If Size is 8 then use Int64Ty
// If Size is 4 then use Int32Ty
// If Size is 2 then use Int16Ty
// If Size is 1 then use Int8Ty
unsigned Size = MemOpLength->getZExtValue();
if (Size == 0 || Size > 8 || (Size&(Size-1)))
return 0; // If not 1/2/4/8, exit.
Type *NewPtrTy = PointerType::getUnqual(IntegerType::get(Size<<3));
// If the memcpy/memmove provides better alignment info than we can
// infer, use it.
SrcAlign = std::max(SrcAlign, CopyAlign);
DstAlign = std::max(DstAlign, CopyAlign);
Value *Src = InsertBitCastBefore(MI->getOperand(2), NewPtrTy, *MI);
Value *Dest = InsertBitCastBefore(MI->getOperand(1), NewPtrTy, *MI);
Value *L = new LoadInst(Src, "tmp", false, SrcAlign, MI);
new StoreInst(L, Dest, false, DstAlign, MI);
return EraseInstFromFunction(*MI);
}
/// visitCallInst - CallInst simplification. This mostly only handles folding
/// of intrinsic instructions. For normal calls, it allows visitCallSite to do
@ -7837,7 +7876,7 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
// If we have a memmove and the source operation is a constant global,
// then the source and dest pointers can't alias, so we can change this
// into a call to memcpy.
if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(II)) {
if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) {
if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource()))
if (GVSrc->isConstant()) {
Module *M = CI.getParent()->getParent()->getParent();
@ -7854,40 +7893,8 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
// If we can determine a pointer alignment that is bigger than currently
// set, update the alignment.
if (isa<MemCpyInst>(MI) || isa<MemMoveInst>(MI)) {
unsigned DstAlign = GetOrEnforceKnownAlignment(MI->getOperand(1), TD);
unsigned SrcAlign = GetOrEnforceKnownAlignment(MI->getOperand(2), TD);
unsigned MinAlign = std::min(DstAlign, SrcAlign);
unsigned CopyAlign = MI->getAlignment()->getZExtValue();
if (CopyAlign < MinAlign) {
MI->setAlignment(ConstantInt::get(Type::Int32Ty, MinAlign));
Changed = true;
}
// If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with
// load/store.
if (ConstantInt *MemOpLength = dyn_cast<ConstantInt>(CI.getOperand(3))) {
// Source and destination pointer types are always "i8*" for intrinsic.
// If Size is 8 then use Int64Ty
// If Size is 4 then use Int32Ty
// If Size is 2 then use Int16Ty
// If Size is 1 then use Int8Ty
unsigned Size = MemOpLength->getZExtValue();
if (Size && Size <= 8 && !(Size&(Size-1))) {
Type *NewPtrTy = PointerType::getUnqual(IntegerType::get(Size<<3));
// If the memcpy/memmove provides better alignment info than we can
// infer, use it.
SrcAlign = std::max(SrcAlign, CopyAlign);
DstAlign = std::max(DstAlign, CopyAlign);
Value *Src = InsertBitCastBefore(CI.getOperand(2), NewPtrTy, CI);
Value *Dest = InsertBitCastBefore(CI.getOperand(1), NewPtrTy, CI);
Value *L = new LoadInst(Src, "tmp", false, SrcAlign, &CI);
Value *NS = new StoreInst(L, Dest, false, DstAlign, &CI);
CI.replaceAllUsesWith(NS);
Changed = true;
return EraseInstFromFunction(CI);
}
}
if (Instruction *I = SimplifyMemTransfer(MI))
return I;
} else if (isa<MemSetInst>(MI)) {
unsigned Alignment = GetOrEnforceKnownAlignment(MI->getDest(), TD);
if (MI->getAlignment()->getZExtValue() < Alignment) {