public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/95556] Not replacing __builtin___memcpy_chk() as documented
Date: Sat, 06 Jun 2020 09:42:31 +0000	[thread overview]
Message-ID: <bug-95556-4-ntdpC2zqjx@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-95556-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95556

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
It is unclear what you are complaining about.

for i in gcc-7 gcc-8 gcc-9 gcc-10 gcc; do echo $i; for j in 1 2 3; do
/usr/src/$i/obj/gcc/cc1 -quiet -O2 pr95556-$j.c; done; grep 'memcpy\|rep.movs'
pr95556-*.s; done
gcc-7
pr95556-1.s:    rep movsq
pr95556-2.s:    call    memcpy
pr95556-3.s:    call    memcpy
gcc-8
pr95556-1.s:    rep movsq
pr95556-2.s:    call    memcpy
pr95556-3.s:    call    memcpy
gcc-9
pr95556-1.s:    rep movsq
pr95556-2.s:    call    memcpy
pr95556-3.s:    call    memcpy
gcc-10
pr95556-1.s:    rep movsq
pr95556-2.s:    rep movsq
pr95556-3.s:    call    memcpy
gcc
pr95556-1.s:    rep movsq
pr95556-2.s:    rep movsq
pr95556-3.s:    call    memcpy

There are no __memcpy_chk calls, which means GCC did in all cases what is
documented, replace the __builtin___memcpy_chk calls with the corresponding
__builtin_memcpy calls and handled that as usually (which isn't always a
library call, there are many different options how a builtin memcpy can be
expanded and one can find tune that through various command line options.  It
depends on what CPU the code is tuned for, whether it is considered hot or cold
code, whether the size is constant and what constant or if it is variable and
what alignment guarantees the destination and source has.

  parent reply	other threads:[~2020-06-06  9:42 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-06  1:22 [Bug c/95556] New: " pgsql@j-davis.com
2020-06-06  1:23 ` [Bug c/95556] " pgsql@j-davis.com
2020-06-06  1:50 ` [Bug middle-end/95556] " pgsql@j-davis.com
2020-06-06  1:53 ` [Bug c/95556] " pgsql@j-davis.com
2020-06-06  9:42 ` jakub at gcc dot gnu.org [this message]
2020-06-06  9:55 ` [Bug middle-end/95556] " jakub at gcc dot gnu.org
2020-06-06  9:59 ` jakub at gcc dot gnu.org
2020-06-06 17:09 ` pgsql@j-davis.com
2020-06-06 17:18 ` jakub at gcc dot gnu.org
2020-06-07 15:31 ` pgsql@j-davis.com
2020-06-07 15:37 ` jakub at gcc dot gnu.org

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-95556-4-ntdpC2zqjx@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).