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From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug inline-asm/23200] [4.2/4.3/4.4 Regression] rejects "i"(&var + 1) Date: Mon, 26 Jan 2009 16:17:00 -0000 [thread overview] Message-ID: <20090126161643.5305.qmail@sourceware.org> (raw) In-Reply-To: <bug-23200-11104@http.gcc.gnu.org/bugzilla/> ------- Comment #40 from amacleod at redhat dot com 2009-01-26 16:16 ------- Created an attachment (id=17185) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17185&action=view) possible patch The problem is due to a check that was added to is_replaceable_p() in tree-ssa-ter.c. I presume this was added by Honza back in 2008-07-19 Jan Hubicka <jh@suse.cz> (is_replaceable_p): Check that locations match; when aliasing is missing be conservative about loads. The check is: if (!optimize && ((locus1 && locus1 != locus2) || (block1 && block1 != block2))) return false; The locus's do not compare equal. This is presumably due to Aldy's enhanced column information which can easily create different locus's for things that are on the same line. I presume this check is an attempt to preserve debug information at some level by not merging expressions from different lines? Honza will have to verify this assumption. I'm also unsure about why blocks for the locus's are compared at the end of the expression. There is a check to make sure the 2 expressions are in the same block a few lines above, so why the locus block check as well? Shouldn't just locus comparing be sufficient? In any case, if the locus block's are not checked, and the locus line numbers are compared if *both* are valid, then the test case work. With -ftree-ter of course. Honza will have to comment on the intent and rationale however, there may be other reasons for that code. A secondary question, why is TER turned off by default with this check in place? It shouldn't destroy any critical debug info if only things that originated on the same line are merged... And on that note, I've added making TER not lose locus's high on my todo list. There is nothing inherent in it that would lose locus info, so I'm presuming there is an oversight in there somewhere. IS that the only problem with TER as far as -O0 goes? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23200
next prev parent reply other threads:[~2009-01-26 16:17 UTC|newest] Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-23200-11104@http.gcc.gnu.org/bugzilla/> 2005-10-29 15:11 ` [Bug inline-asm/23200] [4.0/4.1 regression] " steven at gcc dot gnu dot org 2005-10-31 4:37 ` mmitchel at gcc dot gnu dot org 2005-11-11 8:59 ` bonzini at gcc dot gnu dot org 2005-11-11 9:00 ` bonzini at gcc dot gnu dot org 2006-01-14 5:50 ` [Bug inline-asm/23200] [4.0/4.1/4.2 " pinskia at gcc dot gnu dot org 2006-01-15 23:15 ` mmitchel at gcc dot gnu dot org 2006-01-15 23:23 ` steven at gcc dot gnu dot org 2006-01-19 19:50 ` amacleod at redhat dot com 2006-02-04 0:16 ` mrs at apple dot com 2006-02-24 0:26 ` mmitchel at gcc dot gnu dot org 2006-02-24 2:17 ` mrs at apple dot com 2006-02-24 2:24 ` mark at codesourcery dot com 2006-05-13 8:27 ` stsp at users dot sourceforge dot net 2006-05-25 2:33 ` mmitchel at gcc dot gnu dot org 2006-10-04 22:20 ` jakub at gcc dot gnu dot org 2006-10-04 22:33 ` amacleod at redhat dot com 2006-10-05 19:29 ` stsp at users dot sourceforge dot net 2006-12-08 14:32 ` [Bug inline-asm/23200] [4.0/4.1/4.2/4.3 " amacleod at redhat dot com 2007-02-14 9:06 ` mmitchel at gcc dot gnu dot org 2007-03-10 1:36 ` [Bug inline-asm/23200] [4.0/4.1/4.2 " mmitchel at gcc dot gnu dot org 2007-03-10 1:40 ` mmitchel at gcc dot gnu dot org 2007-03-10 1:41 ` [Bug inline-asm/23200] [4.0/4.1/4.2/4.3 " pinskia at gcc dot gnu dot org 2007-03-12 13:11 ` amacleod at redhat dot com 2007-11-22 15:41 ` jakub at gcc dot gnu dot org 2007-11-22 15:53 ` jakub at gcc dot gnu dot org 2007-11-22 17:27 ` stsp at users dot sourceforge dot net 2008-01-16 22:34 ` [Bug inline-asm/23200] [4.1/4.2/4.3 Regression] " rguenth at gcc dot gnu dot org 2008-01-17 19:09 ` stsp at users dot sourceforge dot net 2008-07-04 20:01 ` [Bug inline-asm/23200] [4.1/4.2/4.3/4.4 " jsm28 at gcc dot gnu dot org 2008-07-05 5:29 ` stsp at users dot sourceforge dot net 2008-07-05 9:41 ` [Bug inline-asm/23200] [4.2/4.3/4.4 " jsm28 at gcc dot gnu dot org 2009-01-25 18:40 ` rguenth at gcc dot gnu dot org 2009-01-26 16:17 ` amacleod at redhat dot com [this message] 2009-03-31 18:54 ` [Bug inline-asm/23200] [4.3/4.4/4.5 " jsm28 at gcc dot gnu dot org 2009-08-04 12:30 ` rguenth at gcc dot gnu dot org 2010-05-22 19:00 ` [Bug inline-asm/23200] [4.3/4.4/4.5/4.6 " rguenth at gcc dot gnu dot org 2010-08-18 22:43 ` pinskia at gcc dot gnu dot org
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