[llvm] [NVPTX] Add syncscope support for cmpxchg (PR #140812)

[Akshay Deodhar via llvm-commits]

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@@ -303,6 +304,7 @@ bool AtomicExpandImpl::processAtomicInstr(Instruction *I) {
 
   if (TLI->shouldInsertFencesForAtomic(I)) {
     auto FenceOrdering = AtomicOrdering::Monotonic;
+    SyncScope::ID SSID = SyncScope::System;
     if (LI && isAcquireOrStronger(LI->getOrdering())) {
       FenceOrdering = LI->getOrdering();
       LI->setOrdering(AtomicOrdering::Monotonic);
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akshayrdeodhar wrote:

The intent was to introduce a mechanism for supporting sycnscope for atomics, and as a first step, support it for CAS.

https://github.com/llvm/llvm-project/pull/140812