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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/64215] -Os misses an opportunity to merge two ret instructions
Date: Mon, 08 Dec 2014 08:52:00 -0000	[thread overview]
Message-ID: <bug-64215-4-Eurp1XH1Dn@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-64215-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64215

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

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

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Reproduced with the trunk too.  The problem is that during cross-jumping (the
"jump2" pass), this isn't cheaply cross-jumpable, as the simple_return just
using earlier computed %eax comes before the bb with setting %eax to -1 and
doing simple_return (so in that case it would be replacement of simple_return
with conditional jump, where the conditional jump is larger).  It is only in
the basic block reordering pass that this is swapped, but that is too late, we
don't have any further crossjumping pass.


  reply	other threads:[~2014-12-08  8:52 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-07 23:36 [Bug target/64215] New: " mpeg.blue at free dot fr
2014-12-08  8:52 ` jakub at gcc dot gnu.org [this message]
2014-12-08 13:25 ` [Bug target/64215] " rguenth at gcc dot gnu.org
2021-08-09  7:36 ` pinskia at gcc dot gnu.org
2022-09-28 20:50 ` tommy_murphy at hotmail dot com
2022-09-28 21:02 ` pinskia at gcc dot gnu.org
2022-09-28 22:34 ` tommy_murphy at hotmail dot com
2023-10-07 19:47 ` law at gcc dot gnu.org

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