https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43147
Allan Jensen <linux at carewolf dot com> changed:
What |Removed |Added
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CC| |linux at carewolf dot com
--- Comment #9 from Allan Jensen <linux at carewolf dot com> ---
(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).
With some other cases there are checks to see if a combined new tree can be
generated as a single instruction and only combined in that case. And as soon
as the compiler have SSSE3 available, we can shuffle anything as single
instruction, so combining them is always safe and fast.
