[PATCH] D112777: [X86][FP16] add alias for *_fmul_pch intrinsics

Craig Topper via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Sun Nov 7 18:12:48 PST 2021


craig.topper added a comment.

In D112777#3114560 <https://reviews.llvm.org/D112777#3114560>, @FreddyYe wrote:

> In D112777#3114502 <https://reviews.llvm.org/D112777#3114502>, @craig.topper wrote:
>
>> Not directly related to this patch, but why is the suffix _pch and _sch when the instruction names end in CPH and CSH? It kind of seems like the correct intrinsic name would have been _mm_fmulc_ph.
>>
>> Why does the name here need to be aligned with mul_ps/pd? This a "complex" multiply which is a different operation. Is gcc also going to add aliases?
>
> I can answer the second question. The prefix "f" can be judged as the mnemonic to distinguish fma instrinsics. The suffix "c" can be judged as the mnemonic of "complex". So add "f" mnemonic in this multiply intrinsics is ambiguous. gcc will add aliases, too. The first question is also a good question. But for now, it's not very conflict to old intrinsics, I think.

But the mnemonic for the instructions here do include an 'F'. While the mulps/mulpd instruction names do not include an 'F'. So we're creating new intrinsics that are further away from the mnemonics of the instructions. Is your argument that the instruction mnemonics are wrong and shouldn't include an 'F'?


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