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From: "gjl at gcc dot gnu.org" <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 16:12:07 +0000	[thread overview]
Message-ID: <bug-114252-4-tg8cyGuZ6N@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-114252-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114252

--- 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?

The point is that there is no need for bswap in the first place, just have a
look at the code that v13 generates.  It's 4 QI loads and that's it, no
shuffling required at all.

But v14 dropped that, and the bswapsi (presumably due to previous flawed tree
optmizations) is introduced by some tree pass.

There's nothing the backend can do about it.  So would you explain why you
think it's a "target" issue?

Maybe the PR title I used is confusing and does not hit the point?

  parent reply	other threads:[~2024-03-06 16:12 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-06 10:01 [Bug tree-optimization/114252] New: " gjl at gcc dot gnu.org
2024-03-06 11:55 ` [Bug target/114252] " rguenth at gcc dot gnu.org
2024-03-06 11:59 ` rguenth at gcc dot gnu.org
2024-03-06 12:15 ` gjl at gcc dot gnu.org
2024-03-06 12:37 ` rguenth at gcc dot gnu.org
2024-03-06 16:12 ` gjl at gcc dot gnu.org [this message]
2024-03-06 17:18 ` rguenther at suse dot de
2024-03-07  7:45 ` rguenth at gcc dot gnu.org
2024-03-07  8:45 ` gjl at gcc dot gnu.org
2024-03-07  9:05 ` gjl at gcc dot gnu.org
2024-03-07  9:14 ` rguenth at gcc dot gnu.org
2024-03-07  9:42 ` rguenth at gcc dot gnu.org
2024-03-07 10:47 ` gjl at gcc dot gnu.org
2024-03-07 10:56 ` rguenth at gcc dot gnu.org
2024-03-07 14:12 ` gjl at gcc dot gnu.org
2024-03-07 15:02 ` pinskia at gcc dot gnu.org
2024-03-07 17:52 ` rguenther at suse dot de

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