public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/113827] MrBayes benchmark redundant load
Date: Fri, 09 Feb 2024 05:10:15 +0000	[thread overview]
Message-ID: <bug-113827-4-mQNfh7R7HY@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-113827-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113827

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Robin Dapp from comment #0)
> A hot block in the MrBayes benchmark (as used in the Phoronix testsuite) has
> a redundant scalar load when vectorized.
> 
> Minimal example, compiled with -march=rv64gcv -O3
> 
> int foo (float **a, float f, int n)
> {
>   for (int i = 0; i < n; i++)
>     {
>       a[i][0] /= f;
>       a[i][1] /= f;
>       a[i][2] /= f;
>       a[i][3] /= f;
>       a[i] += 4;
>     }
> }

LLVM for aarch64 with the above testcase:
``
.L3:
        ldr     x2, [x0]
        mov     x1, x2
        ldr     q31, [x2]
        fdiv    v31.4s, v31.4s, v0.4s
        str     q31, [x1], 16
        str     x1, [x0], 8 ;;;; HERE
        cmp     x3, x0
        bne     .L3
```

There is a store of x1 there.
I really think you messed up reducing the testcase.

      parent reply	other threads:[~2024-02-09  5:10 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-08 11:38 [Bug target/113827] New: " rdapp at gcc dot gnu.org
2024-02-08 14:29 ` [Bug target/113827] MrBayes benchmark redundant load on riscv rdapp at gcc dot gnu.org
2024-02-09  4:28 ` [Bug target/113827] MrBayes benchmark redundant load pinskia at gcc dot gnu.org
2024-02-09  5:10 ` pinskia at gcc dot gnu.org [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=bug-113827-4-mQNfh7R7HY@http.gcc.gnu.org/bugzilla/ \
    --to=gcc-bugzilla@gcc.gnu.org \
    --cc=gcc-bugs@gcc.gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).