Correctly report modified status for ObjCARCOpt

[serge-sans-paille]

Summary

Related to https://reviews.llvm.org/D80916

[foad]

Looks obviously correct.

llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp

bool ObjCARCOpt::OptimizeInlinedAutoreleaseRVCall(
   // Okay, this is a match.  Merge them.
   ++NumPeeps;
   LLVM_DEBUG(dbgs() << "Found inlined objc_autoreleaseReturnValue '"
                     << *AutoreleaseRV << "' paired with '" << *Inst << "'\n");
 
   // Delete the RV pair, starting with the AutoreleaseRV.
   AutoreleaseRV->replaceAllUsesWith(
       cast<CallInst>(AutoreleaseRV)->getArgOperand(0));
+  Changed = true;
   EraseInstruction(AutoreleaseRV);
   if (Class == ARCInstKind::RetainRV) {
     // AutoreleaseRV and RetainRV cancel out.  Delete the RetainRV.
     Inst->replaceAllUsesWith(cast<CallInst>(Inst)->getArgOperand(0));
     EraseInstruction(Inst);
     return true;
   }
 
void ObjCARCOpt::OptimizeIndividualCallImpl(
   // We can delete this call if it takes an inert value.
   SmallPtrSet<Value *, 1> VisitedPhis;
 
   if (IsNoopOnGlobal(Class))
     if (isInertARCValue(Inst->getOperand(0), VisitedPhis)) {
       if (!Inst->getType()->isVoidTy())
         Inst->replaceAllUsesWith(Inst->getOperand(0));
       Inst->eraseFromParent();
+      Changed = true;
       return;
     }
 
   switch (Class) {
   default:
     break;
 
   // Delete no-op casts. These function calls have special semantics, but
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
     ARCInstKind Class = GetBasicARCInstKind(Inst);
     if (Class != ARCInstKind::LoadWeak &&
         Class != ARCInstKind::LoadWeakRetained)
       continue;
 
     // Delete objc_loadWeak calls with no users.
     if (Class == ARCInstKind::LoadWeak && Inst->use_empty()) {
       Inst->eraseFromParent();
+      Changed = true;
       continue;
     }
 
     // TODO: For now, just look for an earlier available version of this value
     // within the same block. Theoretically, we could do memdep-style non-local
     // analysis too, but that would want caching. A better approach would be to
     // use the technique that EarlyCSE uses.
     inst_iterator Current = std::prev(I);