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

[Princeton Ferro via llvm-commits]

================
@@ -6272,10 +6272,12 @@ Instruction *NVPTXTargetLowering::emitLeadingFence(IRBuilderBase &Builder,
 
   // Specialize for cmpxchg
   // Emit a fence.sc leading fence for cmpxchg seq_cst which are not emulated
+  SyncScope::ID SSID = cast<AtomicCmpXchgInst>(Inst)->getSyncScopeID();
   if (isReleaseOrStronger(Ord))
-    return Ord == AtomicOrdering::SequentiallyConsistent
-               ? Builder.CreateFence(AtomicOrdering::SequentiallyConsistent)
-               : Builder.CreateFence(AtomicOrdering::Release);
+    return Builder.CreateFence(Ord == AtomicOrdering::SequentiallyConsistent
+                                   ? AtomicOrdering::SequentiallyConsistent
+                                   : AtomicOrdering::Release,
+                               SSID);
----------------
Prince781 wrote:

nit: I think this looks cleaner, but it's up to you:
```suggestion
    return Builder.CreateFence(Ord == AtomicOrdering::SequentiallyConsistent
                                   ? Ord
                                   : AtomicOrdering::Release,
                               SSID);
```

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