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From: "rakdver at atrey dot karlin dot mff dot cuni dot cz" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/19038] [4.0 Regression] out of ssa causing loops to have more than one BB Date: Fri, 21 Jan 2005 13:22:00 -0000 [thread overview] Message-ID: <20050121132232.7544.qmail@sourceware.org> (raw) In-Reply-To: <20041216155140.19038.dje@gcc.gnu.org> ------- Additional Comments From rakdver at atrey dot karlin dot mff dot cuni dot cz 2005-01-21 13:22 ------- Subject: Re: [4.0 Regression] out of ssa causing loops to have more than one BB > No, tree-ssa-live is quite right. ivtmp.3_12 and ivtmp.3_20 are defined > and live at some common statements, so they conflict: > > # BLOCK 1 > # PRED: 0 [88.4%] (true,exec) 1 [89.0%] (dfs_back,false,exec) > # ivtmp.3_12 = PHI <0(0), ivtmp.3_20(1)>; > <L8>:; > D.501_28 = &__BLNK__.array1[ivtmp.3_12]; > # __BLNK___11 = V_MAY_DEF <__BLNK___2>; > *D.501_28 = 1.0e+0; > ivtmp.3_20 = ivtmp.3_12 + 1; > D.503_30 = D.457_4 - 1; > D.504_31 = (<unnamed type>) D.503_30; > D.505_32 = D.504_31 + 1; > if (ivtmp.3_20 == D.505_32) goto <L12>; else goto <L8>; > # SUCC: 2 [11.0%] (loop_exit,true,exec) 1 [89.0%] (dfs_back,false,exec) > > # BLOCK 2 > # PRED: 1 [11.0%] (loop_exit,true,exec) > <L12>:; > D.497_22 = ivtmp.3_12 + 2; > lsm_tmp.2_23 = (int4) D.497_22; > # j_7 = V_MUST_DEF <j_6>; > j = lsm_tmp.2_23; > # SUCC: 3 [100.0%] (fallthru) > > Between "ivtmp.3_20 = ivtmp.3_12 + 1;" and "D.497_22 = ivtmp.3_12 + 2;" > both versions of ivtmp.3 are live. I have not looked at what causes this, > but IMOH all passes should avoid letting induction variables escape a loop. There's not much to avoid -- the iv is simply used outside of the loop, and we cannot do anything about it. > Interesting note: I think "D.497_22 = ivtmp.3_12 + 2;" could be replaced > with "D.497_22 = ivtmp.3_20 + 1;" which would fix this problem. I think this is how it is immediately after ivopts (if not, it would be a bug); but dom performs this replacement. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19038
next prev parent reply other threads:[~2005-01-21 13:22 UTC|newest] Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-12-16 15:52 [Bug rtl-optimization/19038] New: Loop header copying dje at gcc dot gnu dot org 2004-12-16 21:39 ` [Bug rtl-optimization/19038] " dje at gcc dot gnu dot org 2004-12-16 22:55 ` steven at gcc dot gnu dot org 2004-12-17 4:04 ` pinskia at gcc dot gnu dot org 2004-12-17 4:05 ` pinskia at gcc dot gnu dot org 2004-12-17 4:16 ` pinskia at gcc dot gnu dot org 2004-12-17 4:28 ` pinskia at gcc dot gnu dot org 2004-12-20 18:25 ` [Bug tree-optimization/19038] [4.0 Regression] out-of ssa causing loops to have more than one BB pinskia at gcc dot gnu dot org 2004-12-20 19:04 ` pinskia at gcc dot gnu dot org 2004-12-20 19:23 ` pinskia at gcc dot gnu dot org 2004-12-20 19:47 ` pinskia at gcc dot gnu dot org 2004-12-22 19:03 ` steven at gcc dot gnu dot org 2004-12-23 2:41 ` pinskia at gcc dot gnu dot org 2004-12-23 15:19 ` dje at gcc dot gnu dot org 2004-12-23 16:00 ` steven at gcc dot gnu dot org 2004-12-24 12:13 ` mustafa at il dot ibm dot com 2004-12-24 12:42 ` steven at gcc dot gnu dot org 2004-12-24 12:46 ` steven at gcc dot gnu dot org 2004-12-24 12:52 ` steven at gcc dot gnu dot org 2004-12-24 12:55 ` steven at gcc dot gnu dot org 2004-12-26 1:09 ` dberlin at gcc dot gnu dot org 2004-12-26 15:06 ` pinskia at gcc dot gnu dot org 2004-12-27 21:08 ` law at redhat dot com 2004-12-28 8:22 ` law at redhat dot com 2004-12-28 9:18 ` law at redhat dot com 2004-12-28 23:32 ` law at redhat dot com 2004-12-29 19:33 ` steven at gcc dot gnu dot org 2004-12-29 20:50 ` pinskia at gcc dot gnu dot org 2004-12-29 20:52 ` pinskia at gcc dot gnu dot org 2004-12-29 21:06 ` law at redhat dot com 2004-12-30 17:27 ` pinskia at gcc dot gnu dot org 2004-12-30 18:39 ` law at redhat dot com 2004-12-30 18:49 ` pinskia at gcc dot gnu dot org 2004-12-30 21:51 ` pinskia at gcc dot gnu dot org 2005-01-04 4:04 ` law at redhat dot com 2005-01-04 4:10 ` pinskia at gcc dot gnu dot org 2005-01-10 20:02 ` pinskia at gcc dot gnu dot org 2005-01-12 13:34 ` amacleod at redhat dot com 2005-01-18 0:50 ` [Bug tree-optimization/19038] [4.0 Regression] ivopts " pinskia at gcc dot gnu dot org 2005-01-18 5:02 ` law at redhat dot com 2005-01-19 22:50 ` cvs-commit at gcc dot gnu dot org 2005-01-19 23:25 ` [Bug tree-optimization/19038] [4.0 Regression] out of ssa " pinskia at gcc dot gnu dot org 2005-01-19 23:34 ` pinskia at gcc dot gnu dot org 2005-01-20 0:31 ` pinskia at gcc dot gnu dot org 2005-01-20 0:47 ` pinskia at gcc dot gnu dot org 2005-01-20 1:15 ` pinskia at gcc dot gnu dot org 2005-01-21 13:18 ` steven at gcc dot gnu dot org 2005-01-21 13:22 ` rakdver at atrey dot karlin dot mff dot cuni dot cz [this message] 2005-01-21 13:27 ` steven at gcc dot gnu dot org 2005-01-21 13:29 ` [Bug tree-optimization/19038] [4.0 Regression] tree-ssa " steven at gcc dot gnu dot org 2005-01-21 19:19 ` dberlin at gcc dot gnu dot org 2005-01-22 1:51 ` dberlin at gcc dot gnu dot org 2005-01-22 16:48 ` cvs-commit at gcc dot gnu dot org 2005-01-22 16:49 ` dberlin at gcc dot gnu dot org
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