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

[via llvm-commits]

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@@ -131,7 +131,7 @@ define void @test(ptr %dp0, ptr addrspace(1) %dp1, ptr addrspace(3) %dp3, bfloat
 ; CHECKPTX71-NEXT:    shl.b32 %r51, %r50, %r17;
 ; CHECKPTX71-NEXT:    and.b32 %r52, %r57, %r18;
 ; CHECKPTX71-NEXT:    or.b32 %r53, %r52, %r51;
-; CHECKPTX71-NEXT:    atom.relaxed.shared.cas.b32 %r21, [%r16], %r57, %r53;
+; CHECKPTX71-NEXT:    atom.relaxed.sys.shared.cas.b32 %r21, [%r16], %r57, %r53;
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gonzalobg wrote:

This test has 4 different atomic operations back to back.
I think it'd be good to split it into 4 different tests, otherwise it is a bit hard to review (e.g. I see a few non-atomic ld.global and ld in between, which I'm not sure where they are coming from).
Could that be done in a separate PR that's merged before this one? (and then this one rebased on top?)
@Artem-B thoughts?

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