-/// 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 TargetData.
-static Value *getUnderlyingObjectWithOffset(Value *V, const TargetData *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<GEPOperator>(V)) {
- if (!GEP->hasAllConstantIndices())
- return V;
- SmallVector<Value*, 8> Indices(GEP->op_begin() + 1, GEP->op_end());
- ByteOffset += TD->getIndexedOffset(GEP->getPointerOperandType(),
- &Indices[0], Indices.size());
- V = GEP->getPointerOperand();
- } else if (Operator::getOpcode(V) == Instruction::BitCast) {
- V = cast<Operator>(V)->getOperand(0);
- } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(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.
+/// \brief Check if executing a load of this pointer 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 \c ScanFrom, to determine
+/// if the address is already accessed.
+///
+/// This uses the pointee type to determine how many bytes need to be safe to
+/// load from the pointer.