diff options
Diffstat (limited to 'lib/Transforms')
-rw-r--r-- | lib/Transforms/InstCombine/InstructionCombining.cpp | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp index 21851768cb..4be671f031 100644 --- a/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -849,22 +849,23 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { GetElementPtrInst::Create(Src->getOperand(0), Indices.begin(), Indices.end(), GEP.getName()); } - + // Handle gep(bitcast x) and gep(gep x, 0, 0, 0). Value *StrippedPtr = PtrOp->stripPointerCasts(); - if (StrippedPtr != PtrOp) { - const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType()); + const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType()); + if (StrippedPtr != PtrOp && + StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) { bool HasZeroPointerIndex = false; if (ConstantInt *C = dyn_cast<ConstantInt>(GEP.getOperand(1))) HasZeroPointerIndex = C->isZero(); - + // Transform: GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... // into : GEP [10 x i8]* X, i32 0, ... // // Likewise, transform: GEP (bitcast i8* X to [0 x i8]*), i32 0, ... // into : GEP i8* X, ... - // + // // This occurs when the program declares an array extern like "int X[];" if (HasZeroPointerIndex) { const PointerType *CPTy = cast<PointerType>(PtrOp->getType()); @@ -975,7 +976,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { } } } - + /// See if we can simplify: /// X = bitcast A* to B* /// Y = gep X, <...constant indices...> @@ -983,12 +984,14 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { /// analysis of unions. If "A" is also a bitcast, wait for A/X to be merged. if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) { if (TD && - !isa<BitCastInst>(BCI->getOperand(0)) && GEP.hasAllConstantIndices()) { + !isa<BitCastInst>(BCI->getOperand(0)) && GEP.hasAllConstantIndices() && + StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) { + // Determine how much the GEP moves the pointer. We are guaranteed to get // a constant back from EmitGEPOffset. ConstantInt *OffsetV = cast<ConstantInt>(EmitGEPOffset(&GEP)); int64_t Offset = OffsetV->getSExtValue(); - + // If this GEP instruction doesn't move the pointer, just replace the GEP // with a bitcast of the real input to the dest type. if (Offset == 0) { |