[llvm] AMDGPU: Don't allow s_barrier on gfx12 (PR #81317)

[Jay Foad via llvm-commits]

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@@ -271,7 +272,9 @@ s_cbranch_execnz 0x1234
 // GFX12: s_cbranch_execnz 4660 ; encoding: [0x34,0x12,0xa6,0xbf]
 
 s_barrier
-// GFX12: s_barrier ; encoding: [0x00,0x00,0xbd,0xbf]
+// GFX12-ERR: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
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jayfoad wrote:

Please add this case to gfx12_unsupported.s instead. No need to change the RUN lines in this test.

https://github.com/llvm/llvm-project/pull/81317