public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "ehem+gccbugs at m5p dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/105046] [enhancement] Allow inline-assembly clobbers to overlap inputs
Date: Fri, 25 Mar 2022 21:14:44 +0000	[thread overview]
Message-ID: <bug-105046-4-bXm7R6i0Z1@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-105046-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105046

--- Comment #7 from Elliott M <ehem+gccbugs at m5p dot com> ---
Guess I have to go for the visible use:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/x86/include/asm/xen/hypercall.h

Substantial amounts of the _hypercall#() macro definitions could be removed if
90181 and 105046 were done.  The overhead produced by having no way of choosing
named registers in the asm() construct and not allowing clobbers to overlap
inputs is pretty awful.  This in turn makes this difficult to read.

Additionally, attempting to warn about unused, but set variables becomes
difficult.  Several types of warnings are difficult or impossible since the
source has to lie about what is output versus input.

      parent reply	other threads:[~2022-03-25 21:14 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-24 18:45 [Bug c/105046] New: " ehem+gccbugs at m5p dot com
2022-03-24 19:10 ` [Bug middle-end/105046] " pinskia at gcc dot gnu.org
2022-03-24 19:11 ` pinskia at gcc dot gnu.org
2022-03-24 19:27 ` jakub at gcc dot gnu.org
2022-03-24 21:11 ` [Bug c/105046] " ehem+gccbugs at m5p dot com
2022-03-24 21:16 ` jakub at gcc dot gnu.org
2022-03-24 21:51 ` ehem+gccbugs at m5p dot com
2022-03-25 21:14 ` ehem+gccbugs at m5p dot com [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-105046-4-bXm7R6i0Z1@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).