[clang] [llvm] [PGO] Implement PGO counter promotion for atomic updates (PR #202487)

[David Li via cfe-commits]

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@@ -870,10 +909,29 @@ bool InstrLowerer::isSamplingEnabled() const {
 bool InstrLowerer::isCounterPromotionEnabled() const {
   if (DoCounterPromotion.getNumOccurrences() > 0)
     return DoCounterPromotion;
-
   return Options.DoCounterPromotion;
 }
 
+bool InstrLowerer::isAtomic() const {
+  return Options.Atomic || AtomicCounterUpdateAll;
+}
+
+static void doAtomicPromotionCheck(Function *F) {
+  for (const llvm::Instruction &I : llvm::instructions(F)) {
+    const Value *Addr = nullptr;
+    if (const LoadInst *LI = dyn_cast<LoadInst>(&I))
+      Addr = LI->getOperand(0);
+    else if (const StoreInst *LI = dyn_cast<StoreInst>(&I))
+      Addr = LI->getOperand(1);
+
+    if (Addr && Addr->stripInBoundsOffsets()->getName().starts_with(
+                    getInstrProfCountersVarPrefix())) {
+      LLVM_DEBUG(dbgs() << "Missed candidate: "; I.dump());
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david-xl wrote:

Make the debug message clearer: "Expect atomic update: "

https://github.com/llvm/llvm-project/pull/202487