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Allwo bitcast + struct GEP transform to work with addrspacecast

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llvm-svn: 215467
This commit is contained in:
Matt Arsenault
2014-08-12 19:46:13 +00:00
parent 9744c4af16
commit 4815f09bbe
3 changed files with 48 additions and 3 deletions
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23
llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
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@@ -1667,6 +1667,18 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
if (!DL)
return nullptr;
// addrspacecast between types is canonicalized as a bitcast, then an
// addrspacecast. To take advantage of the below bitcast + struct GEP, look
// through the addrspacecast.
if (AddrSpaceCastInst *ASC = dyn_cast<AddrSpaceCastInst>(PtrOp)) {
// X = bitcast A addrspace(1)* to B addrspace(1)*
// Y = addrspacecast A addrspace(1)* to B addrspace(2)*
// Z = gep Y, <...constant indices...>
// Into an addrspacecasted GEP of the struct.
if (BitCastInst *BC = dyn_cast<BitCastInst>(ASC->getOperand(0)))
PtrOp = BC;
}
/// See if we can simplify:
/// X = bitcast A* to B*
/// Y = gep X, <...constant indices...>
@@ -1675,11 +1687,10 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) {
Value *Operand = BCI->getOperand(0);
PointerType *OpType = cast<PointerType>(Operand->getType());
unsigned OffsetBits = DL->getPointerTypeSizeInBits(OpType);
unsigned OffsetBits = DL->getPointerTypeSizeInBits(GEP.getType());
APInt Offset(OffsetBits, 0);
if (!isa<BitCastInst>(Operand) &&
GEP.accumulateConstantOffset(*DL, Offset) &&
StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) {
GEP.accumulateConstantOffset(*DL, Offset)) {
// If this GEP instruction doesn't move the pointer, just replace the GEP
// with a bitcast of the real input to the dest type.
@@ -1697,6 +1708,9 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
return &GEP;
}
}
if (Operand->getType()->getPointerAddressSpace() != GEP.getAddressSpace())
return new AddrSpaceCastInst(Operand, GEP.getType());
return new BitCastInst(Operand, GEP.getType());
}
@@ -1712,6 +1726,9 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
if (NGEP->getType() == GEP.getType())
return ReplaceInstUsesWith(GEP, NGEP);
NGEP->takeName(&GEP);
if (NGEP->getType()->getPointerAddressSpace() != GEP.getAddressSpace())
return new AddrSpaceCastInst(NGEP, GEP.getType());
return new BitCastInst(NGEP, GEP.getType());
}
}