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From: "rsandifo at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/109632] Inefficient codegen when complex numbers are
 emulated with structs
Date: Thu, 27 Apr 2023 13:33:49 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109632

--- Comment #7 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.or=
g> ---
Thinking more about it, it would probably be better to defer the
split until around lower_complex time, after IPA (especially inlining),
NRV and tail-recursion.  Doing it there should also make it easier
to split arguments.

(In reply to Tamar Christina from comment #6)
> That's an interesting approach, I think it would also fix
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109391 would it not? Since=
 the
> int16x8x3_t return would be "scalarized" avoiding the bad expansion?
I don't think it will help with that, since the returned value
there is a natural V3x8HI (rather than something that the ABI splits
apart).  Splitting in that case might pessimise cases where the
return value is loaded as a whole, rather than assigned to
individually.

But it might be worth giving SRA the option of splitting even
in that case, as a follow-on optimisation, if it fits naturally
with the definitions.=