[llvm] [AMDGPU][GFX11] Do not rewrite V_FMA/FMAC_* to V_FMAAK_F16_t16 on operand legalization. (PR #66202)

[Ivan Kosarev via llvm-commits]

kosarev wrote:

> Oh I see, it's because we are folding a VOP3 instruction (V_FMAC_F16_t16_e64) to V_FMAAK_F16_t16 which is VOP2 only.

Yes. Which I understand makes the shrinking pass the right place to rewrite to V_FMAAK_F16_t16, should we want that.

https://github.com/llvm/llvm-project/pull/66202