- // Conservatively require the attributes of the call to match those of
- // the return. Ignore noalias because it doesn't affect the call sequence.
- const Function *F = ExitBB->getParent();
- AttributeSet CallerAttrs = F->getAttributes();
- if (AttrBuilder(CallerAttrs, AttributeSet::ReturnIndex).
- removeAttribute(Attribute::NoAlias) !=
- AttrBuilder(CallerAttrs, AttributeSet::ReturnIndex).
- removeAttribute(Attribute::NoAlias))
- return false;
+ // Make sure the attributes attached to each return are compatible.
+ AttrBuilder CallerAttrs(F->getAttributes(),
+ AttributeSet::ReturnIndex);
+ AttrBuilder CalleeAttrs(cast<CallInst>(I)->getAttributes(),
+ AttributeSet::ReturnIndex);
+
+ // Noalias is completely benign as far as calling convention goes, it
+ // shouldn't affect whether the call is a tail call.
+ CallerAttrs = CallerAttrs.removeAttribute(Attribute::NoAlias);
+ CalleeAttrs = CalleeAttrs.removeAttribute(Attribute::NoAlias);
+
+ bool AllowDifferingSizes = true;
+ if (CallerAttrs.contains(Attribute::ZExt)) {
+ if (!CalleeAttrs.contains(Attribute::ZExt))
+ return false;
+
+ AllowDifferingSizes = false;
+ CallerAttrs.removeAttribute(Attribute::ZExt);
+ CalleeAttrs.removeAttribute(Attribute::ZExt);
+ } else if (CallerAttrs.contains(Attribute::SExt)) {
+ if (!CalleeAttrs.contains(Attribute::SExt))
+ return false;
+
+ AllowDifferingSizes = false;
+ CallerAttrs.removeAttribute(Attribute::SExt);
+ CalleeAttrs.removeAttribute(Attribute::SExt);
+ }