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

[David Li via cfe-commits]

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@@ -117,6 +119,16 @@ cl::opt<bool> AtomicCounterUpdateAll(
     cl::desc("Make all profile counter updates atomic (for testing only)"),
     cl::init(false));
 
+cl::opt<bool> AtomicCounterPromote(
+    "atomic-counter-promote",
+    cl::desc("Atomize profile counter updates and promote where possible"),
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david-xl wrote:

It is overly conservative -- the order of counter update does not matter, so it can be relaxed.

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