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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug inline-asm/57299] Inline assembly memory dependencies produce spurious loads, register pressure, compilation failures
Date: Wed, 15 May 2013 18:24:00 -0000 [thread overview]
Message-ID: <bug-57299-4-O1NWhwNIJF@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-57299-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57299
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Chris Mihelich from comment #2)
> The asm statement uses only two registers. Of the six inputs and outputs,
> only "r" (p) and "r" (q) are registers; the four "=m" and "m" entries only
> declare that memory is read or written in the assembly code. See the part
> of http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html about memory operands
> (search for "If your assembler instructions access memory").
Since the value of y and x are stored on the stack as they are arguments to the
function, their values need to be loaded into a regsiter first before passing
it on to the inline-asm.
next prev parent reply other threads:[~2013-05-15 18:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-15 18:08 [Bug inline-asm/57299] New: " umbricola at gmail dot com
2013-05-15 18:14 ` [Bug inline-asm/57299] " pinskia at gcc dot gnu.org
2013-05-15 18:22 ` umbricola at gmail dot com
2013-05-15 18:24 ` pinskia at gcc dot gnu.org [this message]
2013-05-15 18:44 ` umbricola at gmail dot com
2013-05-15 18:53 ` pinskia at gcc dot gnu.org
2013-05-15 19:20 ` umbricola at gmail dot com
2013-05-15 20:16 ` pinskia at gcc dot gnu.org
2013-05-15 21:57 ` umbricola at gmail dot com
2013-05-15 21:59 ` pinskia at gcc dot gnu.org
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