[llvm] AMDGPU: Use HasFP8ConversionInsts appropriately, NFC (PR #82024)

[Jay Foad via llvm-commits]

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@@ -898,7 +898,7 @@ multiclass VOP1_Real_NO_DPP_OP_SEL_with_name<GFXGen Gen, bits<9> op,
   VOP1_Real_e32_with_name<Gen, op, opName, asmName>,
   VOP3_Real_with_name<Gen, {0, 1, 1, op{6-0}}, opName, asmName>;
 
-
+let OtherPredicates = [HasFP8ConversionInsts] in {
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jayfoad wrote:

Cc @kosarev @Sisyph

I don't think there's an easy way to _add_ `UseRealTrue16Insts` to `OtherPredicates`.

As a workaround you could set `SubtargetPredicate = HasFP8ConversionInsts` here, instead of using `OtherPredicates`? Or perhaps cleaner we could introduce a new `True16Predicate = ...` for use in `VOP3_Real_dpp8_with_name` to avoid overwriting `OtherPredicates`?

https://github.com/llvm/llvm-project/pull/82024