[llvm] [AMDGPU] Create AMDGPUMnemonicAlias tablegen class (PR #89288)

[Jay Foad via llvm-commits]

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@@ -117,12 +117,16 @@ multiclass EXP_Real_gfx11 {
 multiclass VEXPORT_Real_gfx12 {
   defvar ps = !cast<EXP_Pseudo>(NAME);
   def _gfx12 : EXP_Real_Row<ps, SIEncodingFamily.GFX12, "export">,
-    EXPe_Row, MnemonicAlias<"exp", "export">, Requires<[isGFX12Plus, HasExportInsts]> {
+    EXPe_Row {
     let AssemblerPredicate = isGFX12Only;
     let DecoderNamespace = "GFX12";
     let row = ps.row;
     let done = ps.done;
   }
+  def : AMDGPUMnemonicAlias<"exp", "export"> {
+    let AssemblerPredicate = isGFX12Plus;
+    let OtherPredicates = [HasExportInsts];
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jayfoad wrote:

#91602 removes this predicate. As a further cleanup this alias should be standalone, not inside `VEXPORT_Real_gfx12`, assuming it applies to future generations as well as GFX12.

https://github.com/llvm/llvm-project/pull/89288