[llvm] [AMDGPU][MC]FMA-mix instructions should not be supported in GFX908 etc. (PR #109873)

[Stanislav Mekhanoshin via llvm-commits]

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@@ -1426,7 +1425,6 @@ def FeatureISAVersion9_4_Common : FeatureSet<
   [FeatureGFX9,
    FeatureGFX90AInsts,
    FeatureGFX940Insts,
-   FeatureFmaMixInsts,
----------------
rampitec wrote:

> > I am not saying they are wrong. I am saying it was wrong decision to change instructions and keep the name.
> 
> Could you please elaborate on this? (1) Is the "wrong decision" in the code or in the ISA doc?

In the ISA doc.

> (2) By "change instructions and keep the name", did you mean the mad_mix name is kept in the ISA doc but is actually used for a different instruction than the mad_mix instruction in previous versions, say gfx900?

Yes. And the selection code uses ISD::FMAD to match mad_mix while ISD::FMA for fma_mix.



https://github.com/llvm/llvm-project/pull/109873