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

[Changpeng Fang via llvm-commits]

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@@ -635,8 +635,8 @@ def VOPProfile_Base_CVT_F32_F8_OpSel : VOPProfile<[f32, i32, untyped, untyped]>
   let Src1VOP3DPP = Src1RC64;
 }
 
-let SubtargetPredicate = isGFX12Plus, mayRaiseFPException = 0,
-    SchedRW = [WriteFloatCvt] in {
+let SubtargetPredicate = isGFX12Plus, OtherPredicates = [HasFP8ConversionInsts],
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changpeng wrote:

I think these instructions have gfx940 and gfx12+ versions. Not sure whether it will affect gfx940 if we only use  SubtargetPredicate = HasFP8ConversionInsts. 

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