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From: "gnu_bugzilla_gcc at catelyn dot tech" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/111166] gcc unnecessarily creates vector operations for packing 32 bit integers into struct (x86_64)
Date: Mon, 28 Aug 2023 12:51:15 +0000	[thread overview]
Message-ID: <bug-111166-4-tETvIB4K0D@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-111166-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111166

--- Comment #5 from gnu_bugzilla_gcc at catelyn dot tech ---
(In reply to Richard Biener from comment #4)
> note the situation is difficult to rectify - ideally the vectorizer
> would see that we require two 64bit register pieces but it doesn't - it sees
> we store into memory.

right, I figured that might have been what was going on, given some of the
related issues, the vectorizer incorrectly calculating the cost beforehand

> I'll note the non-vectorized code is also far from optimal.  clang
> produces the following which is faster by more of the delta that
> the vectorized version is slower compared to the scalar GCC variant.

I did notice that the GCC -Os and clang -O3 versions were different, didn't
realize that it was by that much, interesting

  parent reply	other threads:[~2023-08-28 12:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-26 18:29 [Bug tree-optimization/111166] New: " gnu_bugzilla_gcc at catelyn dot tech
2023-08-28  7:37 ` [Bug target/111166] " rguenth at gcc dot gnu.org
2023-08-28 11:49 ` gnu_bugzilla_gcc at catelyn dot tech
2023-08-28 11:52 ` gnu_bugzilla_gcc at catelyn dot tech
2023-08-28 12:37 ` rguenth at gcc dot gnu.org
2023-08-28 12:51 ` gnu_bugzilla_gcc at catelyn dot tech [this message]
2023-08-28 12:53 ` rguenth at gcc dot gnu.org

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