diff options
Diffstat (limited to 'contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp index be0f0e8..9912d3d 100644 --- a/contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp +++ b/contrib/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp @@ -170,14 +170,17 @@ bool MemsetRange::isProfitableToUseMemset(const DataLayout &TD) const { // pessimize the llvm optimizer. // // Since we don't have perfect knowledge here, make some assumptions: assume - // the maximum GPR width is the same size as the pointer size and assume that - // this width can be stored. If so, check to see whether we will end up - // actually reducing the number of stores used. + // the maximum GPR width is the same size as the largest legal integer + // size. If so, check to see whether we will end up actually reducing the + // number of stores used. unsigned Bytes = unsigned(End-Start); - unsigned NumPointerStores = Bytes/TD.getPointerSize(); + unsigned MaxIntSize = TD.getLargestLegalIntTypeSize(); + if (MaxIntSize == 0) + MaxIntSize = 1; + unsigned NumPointerStores = Bytes / MaxIntSize; // Assume the remaining bytes if any are done a byte at a time. - unsigned NumByteStores = Bytes - NumPointerStores*TD.getPointerSize(); + unsigned NumByteStores = Bytes - NumPointerStores * MaxIntSize; // If we will reduce the # stores (according to this heuristic), do the // transformation. This encourages merging 4 x i8 -> i32 and 2 x i16 -> i32 @@ -465,7 +468,7 @@ Instruction *MemCpyOpt::tryMergingIntoMemset(Instruction *StartInst, AMemSet->setDebugLoc(Range.TheStores[0]->getDebugLoc()); // Zap all the stores. - for (SmallVector<Instruction*, 16>::const_iterator + for (SmallVectorImpl<Instruction *>::const_iterator SI = Range.TheStores.begin(), SE = Range.TheStores.end(); SI != SE; ++SI) { MD->removeInstruction(*SI); @@ -626,8 +629,14 @@ bool MemCpyOpt::performCallSlotOptzn(Instruction *cpy, return false; Type *StructTy = cast<PointerType>(A->getType())->getElementType(); - uint64_t destSize = TD->getTypeAllocSize(StructTy); + if (!StructTy->isSized()) { + // The call may never return and hence the copy-instruction may never + // be executed, and therefore it's not safe to say "the destination + // has at least <cpyLen> bytes, as implied by the copy-instruction", + return false; + } + uint64_t destSize = TD->getTypeAllocSize(StructTy); if (destSize < srcSize) return false; } else { |
