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From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/30604] Unable to coalesce ssa_names <x> and <y> which are marked as MUST COALESCE Date: Thu, 08 Mar 2007 20:12:00 -0000 [thread overview] Message-ID: <20070308201216.26205.qmail@sourceware.org> (raw) In-Reply-To: <bug-30604-3639@http.gcc.gnu.org/bugzilla/> ------- Comment #7 from amacleod at redhat dot com 2007-03-08 20:12 ------- Looking at the original testcase, the complaint is that _t_8232 and _t_3 are both used in the PHI definition of _t_7. (using mainline from march 5th) ie, _t_7(ab) = PHI <...., _t_8232, ... , _t_3, ...> That definition occurs in BB2509. Because its an abnormal edge, all three must be coalescable. _t_8232 is defined in BB 2315, but _t_3 is live on entry and through this block, meaning they have different values and are live at the same time, so they cannot be coalesced The listing looks OK after ccp2, but in the listing after the FRE pass _t_3 becomes live on entry to this block, and it wasn't before. I can't really read the detailed output from FRE, but it does seem to have replaced a bunch of expressions with _t_3, so that would appear to be the culprit. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30604
next prev parent reply other threads:[~2007-03-08 20:12 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-01-26 20:29 [Bug tree-optimization/30604] New: " mark at gcc dot gnu dot org 2007-01-26 20:35 ` [Bug tree-optimization/30604] " mark at gcc dot gnu dot org 2007-01-28 19:26 ` pinskia at gcc dot gnu dot org 2007-02-01 15:01 ` aph at gcc dot gnu dot org 2007-02-01 15:23 ` mark at gcc dot gnu dot org 2007-03-08 9:04 ` tbm at cyrius dot com 2007-03-08 9:05 ` tbm at cyrius dot com 2007-03-08 12:34 ` pinskia at gcc dot gnu dot org 2007-03-08 20:12 ` amacleod at redhat dot com [this message] 2007-03-10 0:01 ` Daniel Berlin 2007-03-08 20:21 ` amacleod at redhat dot com 2007-03-10 0:02 ` dberlin at dberlin dot org 2007-03-12 13:34 ` amacleod at redhat dot com 2007-11-09 15:37 ` amacleod at redhat dot com 2007-11-09 18:27 ` pinskia at gcc dot gnu dot org 2007-11-09 18:41 ` amacleod at redhat dot com 2008-02-15 12:56 ` rguenth at gcc dot gnu dot org [not found] <bug-30604-4@http.gcc.gnu.org/bugzilla/> 2013-06-06 8:59 ` dcb314 at hotmail dot com 2013-06-06 9:51 ` rguenther at suse dot de 2020-07-28 2:04 ` asolokha at gmx dot com 2020-07-28 5:54 ` rguenth at gcc dot gnu.org
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