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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/114252] Introducing bswapsi reduces code performance
Date: Wed, 06 Mar 2024 17:18:23 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114252

--- Comment #6 from rguenther at suse dot de <rguenther at suse dot de> ---
> Am 06.03.2024 um 17:12 schrieb gjl at gcc dot gnu.org <gcc-bugzilla@gcc.g=
nu.org>:
>=20
> =EF=BB=BFhttps://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114252
>=20
> --- Comment #5 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
> (In reply to Richard Biener from comment #4)
>> So bswap on a value is just register shuffling, right?
>=20
> The point is that there is no need for bswap in the first place, just hav=
e a
> look at the code that v13 generates.  It's 4 QI loads and that's it, no
> shuffling required at all.
>=20
> But v14 dropped that, and the bswapsi (presumably due to previous flawed =
tree
> optmizations) is introduced by some tree pass.
>=20
> There's nothing the backend can do about it.  So would you explain why you
> think it's a "target" issue?
>=20
> Maybe the PR title I used is confusing and does not hit the point?

Why does the target say it has bswapsi then? In which case is that profitab=
le?

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