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

[via llvm-commits]

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@@ -43,21 +43,21 @@ define i8 @monotonic_monotonic_i8_generic(ptr %addr, i8 %cmp, i8 %new) {
 ; SM70-NEXT:  $L__BB0_3: // %partword.cmpxchg.end
 ; SM70-NEXT:    st.param.b32 [func_retval0], %r13;
 ; SM70-NEXT:    ret;
-    %pairold = cmpxchg ptr %addr, i8 %cmp, i8 %new monotonic monotonic
+    %pairold = cmpxchg ptr %addr, i8 %cmp, i8 %new syncscope("") monotonic monotonic
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gonzalobg wrote:

Is this change required or just auto-generated from the python scripts?
I believe the default should already be `syncscope("")` which maps to `System`.
I think we should test somewhere that the system scope ones produce the same code with and without `syncscope("")`.

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