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From: "glisse at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/58387] [4.9 Regression] wrong code at -Os and above on x86_64-linux-gnu (both 32-bit and 64-bit modes)
Date: Fri, 13 Sep 2013 19:18:00 -0000	[thread overview]
Message-ID: <bug-58387-4-7vFSXYjw4B@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-58387-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58387

--- Comment #21 from Marc Glisse <glisse at gcc dot gnu.org> ---
Thanks Jeff, sounds great :-)

Even if we mark that a statement is not reachable, we probably won't eliminate
many functions with side-effects executed before, since (I guess) we must be
able to prove that they always return normally (no longjmp or throwing an
exception or going into an infinite loop or anything fancy that would avoid
coming back to execute the undefined-behavior statement), and I don't know if
we can prove that for more than a few builtins and inline functions (maybe more
with LTO).

PS: I secretly hope that one of your jump-threading improvements will magically
help with PR 55860 ;-)


  parent reply	other threads:[~2013-09-13 19:18 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-10 23:10 [Bug middle-end/58387] New: " su at cs dot ucdavis.edu
2013-09-11  5:17 ` [Bug middle-end/58387] " jakub at gcc dot gnu.org
2013-09-11  5:22 ` su at cs dot ucdavis.edu
2013-09-11  6:13 ` jakub at gcc dot gnu.org
2013-09-11  7:10 ` su at cs dot ucdavis.edu
2013-09-11 15:04 ` su at cs dot ucdavis.edu
2013-09-11 16:50 ` [Bug middle-end/58387] [4.9 Regression] " hjl.tools at gmail dot com
2013-09-12 21:19 ` hjl.tools at gmail dot com
2013-09-12 21:29 ` law at redhat dot com
2013-09-13  3:35 ` law at redhat dot com
2013-09-13  6:02 ` law at redhat dot com
2013-09-13  7:10 ` su at cs dot ucdavis.edu
2013-09-13 11:10 ` markus at trippelsdorf dot de
2013-09-13 15:28 ` law at redhat dot com
2013-09-13 15:48 ` su at cs dot ucdavis.edu
2013-09-13 16:02 ` law at redhat dot com
2013-09-13 16:25 ` joseph at codesourcery dot com
2013-09-13 16:33 ` law at redhat dot com
2013-09-13 17:31 ` glisse at gcc dot gnu.org
2013-09-13 18:00 ` law at redhat dot com
2013-09-13 19:18 ` glisse at gcc dot gnu.org [this message]
2013-09-17 18:39 ` law at redhat dot com

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