diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp index 73aa8b49cda5..2c72a976ba58 100644 --- a/llvm/lib/Analysis/Loads.cpp +++ b/llvm/lib/Analysis/Loads.cpp @@ -13,6 +13,7 @@ #include "llvm/Analysis/Loads.h" #include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/Analysis/ValueTracking.h" #include "llvm/DataLayout.h" #include "llvm/GlobalAlias.h" #include "llvm/GlobalVariable.h" @@ -48,48 +49,19 @@ static bool AreEquivalentAddressValues(const Value *A, const Value *B) { return false; } -/// getUnderlyingObjectWithOffset - Strip off up to MaxLookup GEPs and -/// bitcasts to get back to the underlying object being addressed, keeping -/// track of the offset in bytes from the GEPs relative to the result. -/// This is closely related to GetUnderlyingObject but is located -/// here to avoid making VMCore depend on DataLayout. -static Value *getUnderlyingObjectWithOffset(Value *V, const DataLayout *TD, - uint64_t &ByteOffset, - unsigned MaxLookup = 6) { - if (!V->getType()->isPointerTy()) - return V; - for (unsigned Count = 0; MaxLookup == 0 || Count < MaxLookup; ++Count) { - if (GEPOperator *GEP = dyn_cast(V)) { - if (!GEP->hasAllConstantIndices()) - return V; - SmallVector Indices(GEP->op_begin() + 1, GEP->op_end()); - ByteOffset += TD->getIndexedOffset(GEP->getPointerOperandType(), - Indices); - V = GEP->getPointerOperand(); - } else if (Operator::getOpcode(V) == Instruction::BitCast) { - V = cast(V)->getOperand(0); - } else if (GlobalAlias *GA = dyn_cast(V)) { - if (GA->mayBeOverridden()) - return V; - V = GA->getAliasee(); - } else { - return V; - } - assert(V->getType()->isPointerTy() && "Unexpected operand type!"); - } - return V; -} - /// isSafeToLoadUnconditionally - Return true if we know that executing a load /// from this value cannot trap. If it is not obviously safe to load from the /// specified pointer, we do a quick local scan of the basic block containing /// ScanFrom, to determine if the address is already accessed. bool llvm::isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom, unsigned Align, const DataLayout *TD) { - uint64_t ByteOffset = 0; + int64_t ByteOffset = 0; Value *Base = V; if (TD) - Base = getUnderlyingObjectWithOffset(V, TD, ByteOffset); + Base = GetPointerBaseWithConstantOffset(V, ByteOffset, *TD); + + if (ByteOffset < 0) // out of bounds + return false; Type *BaseType = 0; unsigned BaseAlign = 0; @@ -97,10 +69,10 @@ bool llvm::isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom, // An alloca is safe to load from as load as it is suitably aligned. BaseType = AI->getAllocatedType(); BaseAlign = AI->getAlignment(); - } else if (const GlobalValue *GV = dyn_cast(Base)) { + } else if (const GlobalVariable *GV = dyn_cast(Base)) { // Global variables are safe to load from but their size cannot be // guaranteed if they are overridden. - if (!isa(GV) && !GV->mayBeOverridden()) { + if (!GV->mayBeOverridden()) { BaseType = GV->getType()->getElementType(); BaseAlign = GV->getAlignment(); }