- // The address of an aligned GlobalValue has trailing zeros.
- if (auto *GO = dyn_cast<GlobalObject>(V)) {
- unsigned Align = GO->getAlignment();
- if (Align == 0) {
- if (auto *GVar = dyn_cast<GlobalVariable>(GO)) {
- Type *ObjectType = GVar->getType()->getElementType();
- if (ObjectType->isSized()) {
- // If the object is defined in the current Module, we'll be giving
- // it the preferred alignment. Otherwise, we have to assume that it
- // may only have the minimum ABI alignment.
- if (GVar->isStrongDefinitionForLinker())
- Align = DL.getPreferredAlignment(GVar);
- else
- Align = DL.getABITypeAlignment(ObjectType);
- }
- }
- }
- if (Align > 0)
- KnownZero = APInt::getLowBitsSet(BitWidth,
- countTrailingZeros(Align));
- else
- KnownZero.clearAllBits();
- KnownOne.clearAllBits();
- return;
- }
-
- if (Argument *A = dyn_cast<Argument>(V)) {
- unsigned Align = A->getType()->isPointerTy() ? A->getParamAlignment() : 0;
-
- if (!Align && A->hasStructRetAttr()) {
- // An sret parameter has at least the ABI alignment of the return type.
- Type *EltTy = cast<PointerType>(A->getType())->getElementType();
- if (EltTy->isSized())
- Align = DL.getABITypeAlignment(EltTy);
- }
-
- if (Align)
- KnownZero = APInt::getLowBitsSet(BitWidth, countTrailingZeros(Align));
- else
- KnownZero.clearAllBits();
- KnownOne.clearAllBits();
-
- // Don't give up yet... there might be an assumption that provides more
- // information...
- computeKnownBitsFromAssume(V, KnownZero, KnownOne, DL, Depth, Q);
-
- // Or a dominating condition for that matter
- if (EnableDomConditions && Depth <= DomConditionsMaxDepth)
- computeKnownBitsFromDominatingCondition(V, KnownZero, KnownOne, DL,
- Depth, Q);
- return;
- }
-