https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43147
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Marc Glisse from comment #6)
> Created attachment 45303 [details]
> example patch (untested)
>
> Making the meaning of shuffles visible in GIMPLE could help a bit (although
> it wouldn't solve the problem completely because IIRC we don't dare combine
> shuffles, since it is hard to find an optimal expansion for a shuffle and we
> might pessimize some cases).
> This patch is one simple way to make _mm_shuffle_pd less opaque.
> _mm_shuffle_ps would be a bit longer but still manageable. It has the
> drawback that it does not diagnose when the mask is not a constant, or not
> between 0 and 3, and I am not sure how to do that from the C code. An
> alternative would be to keep the current builtin but turn it into a
> vec_perm_expr in ix86_gimple_fold_builtin, which could include diagnostics.
I think doing it in ix86_gimple_fold_builtin is better.
