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

[Changpeng Fang 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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changpeng wrote:

This is a little complicate. For _DPP8 and DPP16 reals, only OtherPredicates is copied from pseudo.
However, in VOP3_Real_dpp8_with_name, OtherPredicates is over-written after copied from pseudo:
 OtherPredicates = !if(ps.Pfl.IsRealTrue16, [UseRealTrue16Insts], [TruePredicate])
Can we also keep original OtherPredcates (copied from pseudo) when we add UseRealTrue16Insts?

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