[llvm] [AtomicExpandPass] Improve atomic expand error messages (PR #188380)

[Yonah Goldberg via llvm-commits]

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@@ -1,9 +1,9 @@
 ; RUN: not llc -mtriple=nvptx64 -mcpu=sm_30 -filetype=null %s 2>&1 | FileCheck %s
 
-; CHECK: error: unsupported cmpxchg
-; CHECK: error: unsupported cmpxchg
-; CHECK: error: unsupported cmpxchg
-; CHECK: error: unsupported cmpxchg
+; CHECK-DAG: error: unsupported atomicrmw and: instruction alignment 16 is smaller than the required 32-byte alignment for this atomic operation; target supports atomics up to 8 bytes, but this atomic accesses 32 bytes
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YonahGoldberg wrote:

It was so that order of checks doesn't matter, but I don't really need that.

https://github.com/llvm/llvm-project/pull/188380