[llvm] AMDGPU: Add an argument to DS_Real_gfx12 to disable alias, NFC (PR #84717)

[Jay Foad via llvm-commits]

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@@ -1210,13 +1210,13 @@ class Base_DS_Real_gfx6_gfx7_gfx10_gfx11_gfx12<bits<8> op, DS_Pseudo ps, int ef,
 // GFX12.
 //===----------------------------------------------------------------------===//
 
-multiclass DS_Real_gfx12<bits<8> op, string name = !tolower(NAME)> {
+multiclass DS_Real_gfx12<bits<8> op, string name = !tolower(NAME), int needAlias = true> {
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jayfoad wrote:

```suggestion
multiclass DS_Real_gfx12<bits<8> op, string name = !tolower(NAME), bit needAlias = true> {
```

https://github.com/llvm/llvm-project/pull/84717