[AMDGPU] Cosmetic tweaks in AMDGPUAtomicOptimizer. NFC. (#129081)

Simplify iteration over the ToReplace vector, and some related cosmetic
cleanups.

Author: jayfoad

llvm/lib/Target/AMDGPU/AMDGPUAtomicOptimizer.cpp

@@ -151,23 +151,18 @@ PreservedAnalyses AMDGPUAtomicOptimizerPass::run(Function &F,
 }
 
 bool AMDGPUAtomicOptimizerImpl::run() {
-
   // Scan option None disables the Pass
-  if (ScanImpl == ScanOptions::None) {
+  if (ScanImpl == ScanOptions::None)
     return false;
-  }
 
   visit(F);
+  if (ToReplace.empty())
+    return false;
 
-  const bool Changed = !ToReplace.empty();
-
-  for (ReplacementInfo &Info : ToReplace) {
-    optimizeAtomic(*Info.I, Info.Op, Info.ValIdx, Info.ValDivergent);
-  }
-
+  for (auto &[I, Op, ValIdx, ValDivergent] : ToReplace)
+    optimizeAtomic(*I, Op, ValIdx, ValDivergent);
   ToReplace.clear();
-
-  return Changed;
+  return true;
 }
 
 static bool isLegalCrossLaneType(Type *Ty) {
@@ -247,9 +242,7 @@ void AMDGPUAtomicOptimizerImpl::visitAtomicRMWInst(AtomicRMWInst &I) {
   // If we get here, we can optimize the atomic using a single wavefront-wide
   // atomic operation to do the calculation for the entire wavefront, so
   // remember the instruction so we can come back to it.
-  const ReplacementInfo Info = {&I, Op, ValIdx, ValDivergent};
-
-  ToReplace.push_back(Info);
+  ToReplace.push_back({&I, Op, ValIdx, ValDivergent});
 }
 
 void AMDGPUAtomicOptimizerImpl::visitIntrinsicInst(IntrinsicInst &I) {
@@ -333,17 +326,14 @@ void AMDGPUAtomicOptimizerImpl::visitIntrinsicInst(IntrinsicInst &I) {
   // If any of the other arguments to the intrinsic are divergent, we can't
   // optimize the operation.
   for (unsigned Idx = 1; Idx < I.getNumOperands(); Idx++) {
-    if (UA.isDivergentUse(I.getOperandUse(Idx))) {
+    if (UA.isDivergentUse(I.getOperandUse(Idx)))
       return;
-    }
   }
 
   // If we get here, we can optimize the atomic using a single wavefront-wide
   // atomic operation to do the calculation for the entire wavefront, so
   // remember the instruction so we can come back to it.
-  const ReplacementInfo Info = {&I, Op, ValIdx, ValDivergent};
-
-  ToReplace.push_back(Info);
+  ToReplace.push_back({&I, Op, ValIdx, ValDivergent});
 }
 
 // Use the builder to create the non-atomic counterpart of the specified