diff options
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineCasts.cpp')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineCasts.cpp | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp index 356803a..ff083d7 100644 --- a/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -1434,7 +1434,12 @@ Instruction *InstCombiner::commonPointerCastTransforms(CastInst &CI) { if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) { // If casting the result of a getelementptr instruction with no offset, turn // this into a cast of the original pointer! - if (GEP->hasAllZeroIndices()) { + if (GEP->hasAllZeroIndices() && + // If CI is an addrspacecast and GEP changes the poiner type, merging + // GEP into CI would undo canonicalizing addrspacecast with different + // pointer types, causing infinite loops. + (!isa<AddrSpaceCastInst>(CI) || + GEP->getType() == GEP->getPointerOperand()->getType())) { // Changing the cast operand is usually not a good idea but it is safe // here because the pointer operand is being replaced with another // pointer operand so the opcode doesn't need to change. @@ -1904,5 +1909,24 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) { } Instruction *InstCombiner::visitAddrSpaceCast(AddrSpaceCastInst &CI) { + // If the destination pointer element type is not the the same as the source's + // do the addrspacecast to the same type, and then the bitcast in the new + // address space. This allows the cast to be exposed to other transforms. + Value *Src = CI.getOperand(0); + PointerType *SrcTy = cast<PointerType>(Src->getType()->getScalarType()); + PointerType *DestTy = cast<PointerType>(CI.getType()->getScalarType()); + + Type *DestElemTy = DestTy->getElementType(); + if (SrcTy->getElementType() != DestElemTy) { + Type *MidTy = PointerType::get(DestElemTy, SrcTy->getAddressSpace()); + if (VectorType *VT = dyn_cast<VectorType>(CI.getType())) { + // Handle vectors of pointers. + MidTy = VectorType::get(MidTy, VT->getNumElements()); + } + + Value *NewBitCast = Builder->CreateBitCast(Src, MidTy); + return new AddrSpaceCastInst(NewBitCast, CI.getType()); + } + return commonPointerCastTransforms(CI); } |