Correctly update return status for MVEGatherScatterLowering

[serge-sans-paille]

Summary

Correctly reflect change in the return status.

Patch needed to land https://reviews.llvm.org/D80916

[foad]

Looks obvious to me but I'd prefer an ARM maintainer to review it.

[anwel]

LGTM - Changed should indeed reflect possible changes by that function, too.

llvm/lib/Target/ARM/MVEGatherScatterLowering.cpp

bool MVEGatherScatterLowering::runOnFunction(Function &F) {
   auto &TM = TPC.getTM<TargetMachine>();
   auto *ST = &TM.getSubtarget<ARMSubtarget>(F);
   if (!ST->hasMVEIntegerOps())
     return false;
   LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
   SmallVector<IntrinsicInst *, 4> Gathers;
   SmallVector<IntrinsicInst *, 4> Scatters;
 
+  bool Changed = false;
+
   for (BasicBlock &BB : F) {
     for (Instruction &I : BB) {
       IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
       if (II && II->getIntrinsicID() == Intrinsic::masked_gather) {
         Gathers.push_back(II);
         if (isa<GetElementPtrInst>(II->getArgOperand(0)))
-          optimiseOffsets(
+          Changed |= optimiseOffsets(
               cast<Instruction>(II->getArgOperand(0))->getOperand(1),
               II->getParent(), LI);
       } else if (II && II->getIntrinsicID() == Intrinsic::masked_scatter) {
         Scatters.push_back(II);
         if (isa<GetElementPtrInst>(II->getArgOperand(1)))
-          optimiseOffsets(
+          Changed |= optimiseOffsets(
               cast<Instruction>(II->getArgOperand(1))->getOperand(1),
               II->getParent(), LI);
       }
     }
   }
 
-  bool Changed = false;
   for (unsigned i = 0; i < Gathers.size(); i++) {
     IntrinsicInst *I = Gathers[i];
     Value *L = lowerGather(I);
     if (L == nullptr)
       continue;
 
     // Get rid of any now dead instructions
     SimplifyInstructionsInBlock(cast<Instruction>(L)->getParent());