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From: "glisse at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/59615] "asm goto" output or at least clobbered operands
Date: Mon, 30 Dec 2013 17:53:00 -0000	[thread overview]
Message-ID: <bug-59615-4-MzqFb8akSc@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-59615-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59615

--- Comment #6 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #4)
> Anyway, you definitely don't want
> to use inline asm in this case, if there is some code GCC doesn't optimize
> as good as you'd like to, just report that.

One common similar case where people are tempted to use asm goto with an output
operand is, on x86: compute a*b and check if it overflowed. x86 has flags for
that but AFAIR they are not modeled in the .md files. (I was also interested in
output operands for asm goto in PR52381, but there is no good example there)


  parent reply	other threads:[~2013-12-30 17:53 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-28  0:23 [Bug c/59615] New: " hpa at zytor dot com
2013-12-28  8:42 ` [Bug c/59615] " jakub at gcc dot gnu.org
2013-12-28 10:29 ` ubizjak at gmail dot com
2013-12-28 16:28 ` jakub at gcc dot gnu.org
2013-12-30  1:37 ` hpa at zytor dot com
2013-12-30 17:53 ` glisse at gcc dot gnu.org [this message]
2013-12-30 17:56 ` jakub at gcc dot gnu.org
2013-12-30 18:17 ` glisse at gcc dot gnu.org
2021-09-01  1:05 ` [Bug inline-asm/59615] " pinskia at gcc dot gnu.org

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