diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/IPO/GlobalOpt.cpp | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp index 9d98bb156b4..371500bc786 100644 --- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp +++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp @@ -241,15 +241,15 @@ static bool AnalyzeGlobal(const Value *V, GlobalStatus &GS, GS.HasPHIUser = true; } else if (isa<CmpInst>(I)) { GS.isCompared = true; - } else if (isa<MemTransferInst>(I)) { - const MemTransferInst *MTI = cast<MemTransferInst>(I); + } else if (const MemTransferInst *MTI = dyn_cast<MemTransferInst>(I)) { + if (MTI->isVolatile()) return true; if (MTI->getArgOperand(0) == V) GS.StoredType = GlobalStatus::isStored; if (MTI->getArgOperand(1) == V) GS.isLoaded = true; - } else if (isa<MemSetInst>(I)) { - assert(cast<MemSetInst>(I)->getArgOperand(0) == V && - "Memset only takes one pointer!"); + } else if (const MemSetInst *MSI = dyn_cast<MemSetInst>(I)) { + assert(MSI->getArgOperand(0) == V && "Memset only takes one pointer!"); + if (MSI->isVolatile()) return true; GS.StoredType = GlobalStatus::isStored; } else { return true; // Any other non-load instruction might take address! @@ -2438,6 +2438,20 @@ static bool EvaluateFunction(Function *F, Constant *&RetVal, // Cannot handle inline asm. if (isa<InlineAsm>(CI->getCalledValue())) return false; + if (MemSetInst *MSI = dyn_cast<MemSetInst>(CI)) { + if (MSI->isVolatile()) return false; + Constant *Ptr = getVal(Values, MSI->getDest()); + Constant *Val = getVal(Values, MSI->getValue()); + Constant *DestVal = ComputeLoadResult(getVal(Values, Ptr), + MutatedMemory); + if (Val->isNullValue() && DestVal->isNullValue()) { + // This memset is a no-op. + ++CurInst; + continue; + } + return false; + } + // Resolve function pointers. Function *Callee = dyn_cast<Function>(getVal(Values, CI->getCalledValue())); |
