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From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/42108] [4.4/4.5 Regression] Vectorizer cannot deal with PAREN_EXPR gracefully, 50% performance regression Date: Thu, 19 Nov 2009 16:50:00 -0000 [thread overview] Message-ID: <20091119164952.27758.qmail@sourceware.org> (raw) In-Reply-To: <bug-42108-9410@http.gcc.gnu.org/bugzilla/> ------- Comment #2 from rguenth at gcc dot gnu dot org 2009-11-19 16:49 ------- -ftree-vectorizer-verbose=2 tells you: eval.f90:35: note: not vectorized: relevant stmt not supported: D.1684_73 = ((D.1683_72)); eval.f90:32: note: not vectorized: relevant stmt not supported: D.1684_58 = ((D.1683_57)); PAREN_EXPRs are new in 4.4 and I believe they cannot be turned off right now. The loops are do i=1,nnd x(i) = 1.d0 + (1.d0*i)/nnd end do do i=1,n foo4(i) = 1.d0 + (1.d0*i)/n end do where the vectorizer doesn't know how to ensure evaluation order is preserved when trying to vectorize (1.d0*i)/n. Writing them as 1.d0*i/n vectorizes the function. Still the performance is lower by a factor of two compared to 4.3 (even with -ffast-math). Probably the bug should be split. -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |irar at il dot ibm dot com, | |rguenth at gcc dot gnu dot | |org Severity|normal |enhancement Status|UNCONFIRMED |NEW Component|fortran |tree-optimization Ever Confirmed|0 |1 Keywords| |missed-optimization Last reconfirmed|0000-00-00 00:00:00 |2009-11-19 16:49:51 date| | Summary|Performance drop from 4.3 to|[4.4/4.5 Regression] |4.4/4.5 |Vectorizer cannot deal with | |PAREN_EXPR gracefully, 50% | |performance regression Target Milestone|--- |4.4.3 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42108
next prev parent reply other threads:[~2009-11-19 16:50 UTC|newest] Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-11-19 16:01 [Bug fortran/42108] New: Performance drop from 4.3 to 4.4/4.5 sfilippone at uniroma2 dot it 2009-11-19 16:01 ` [Bug fortran/42108] " sfilippone at uniroma2 dot it 2009-11-19 16:50 ` rguenth at gcc dot gnu dot org [this message] 2009-11-19 17:17 ` [Bug tree-optimization/42108] [4.4/4.5 Regression] Vectorizer cannot deal with PAREN_EXPR gracefully, 50% performance regression sfilippone at uniroma2 dot it 2009-11-19 17:30 ` rguenther at suse dot de 2009-11-19 19:42 ` sfilippone at uniroma2 dot it 2009-11-19 19:53 ` toon at moene dot org 2009-11-19 22:33 ` anlauf at gmx dot de 2009-11-20 8:32 ` sfilippone at uniroma2 dot it 2009-11-20 13:45 ` dominiq at lps dot ens dot fr 2009-11-20 14:04 ` sfilippone at uniroma2 dot it 2009-11-20 14:12 ` sfilippone at uniroma2 dot it 2009-11-20 14:14 ` rguenth at gcc dot gnu dot org 2009-11-20 19:45 ` toon at moene dot org 2009-11-20 23:48 ` rguenth at gcc dot gnu dot org 2009-11-21 12:11 ` toon at moene dot org 2009-11-21 12:19 ` rguenther at suse dot de 2009-11-21 13:58 ` rguenth at gcc dot gnu dot org 2009-11-23 9:02 ` irar at il dot ibm dot com 2009-11-27 11:23 ` rguenth at gcc dot gnu dot org 2009-11-30 8:53 ` irar at il dot ibm dot com 2009-11-30 8:54 ` irar at il dot ibm dot com 2009-11-30 10:13 ` rguenther at suse dot de 2009-11-30 12:21 ` irar at il dot ibm dot com 2009-12-04 14:25 ` [Bug tree-optimization/42108] [4.4/4.5 Regression] " dominiq at lps dot ens dot fr 2009-12-13 23:48 ` matz at gcc dot gnu dot org 2009-12-14 4:55 ` matz at gcc dot gnu dot org 2009-12-14 5:26 ` matz at gcc dot gnu dot org 2009-12-14 10:51 ` dominiq at lps dot ens dot fr 2009-12-14 11:21 ` dominiq at lps dot ens dot fr 2009-12-14 11:23 ` rguenth at gcc dot gnu dot org 2009-12-14 11:50 ` rguenth at gcc dot gnu dot org 2009-12-14 12:27 ` rguenther at suse dot de 2009-12-14 12:30 ` rguenth at gcc dot gnu dot org 2009-12-14 12:58 ` rguenth at gcc dot gnu dot org 2009-12-14 16:58 ` matz at gcc dot gnu dot org 2009-12-15 7:10 ` tkoenig at gcc dot gnu dot org 2009-12-15 11:08 ` rguenth at gcc dot gnu dot org 2009-12-18 15:43 ` rguenth at gcc dot gnu dot org 2009-12-18 21:04 ` dominiq at lps dot ens dot fr 2009-12-18 21:40 ` matz at gcc dot gnu dot org 2009-12-18 23:44 ` rguenth at gcc dot gnu dot org 2009-12-19 11:25 ` rguenth at gcc dot gnu dot org 2009-12-19 19:29 ` rguenth at gcc dot gnu dot org 2009-12-19 19:41 ` rguenth at gcc dot gnu dot org 2009-12-19 21:10 ` rguenth at gcc dot gnu dot org 2010-01-21 13:15 ` jakub at gcc dot gnu dot org 2010-04-05 12:53 ` steven at gcc dot gnu dot org 2010-04-05 12:54 ` rguenther at suse dot de 2010-04-05 12:57 ` rguenther at suse dot de 2010-04-05 13:02 ` steven at gcc dot gnu dot org 2010-04-05 14:23 ` rguenth at gcc dot gnu dot org 2010-04-30 8:55 ` [Bug tree-optimization/42108] [4.4/4.5/4.6 " jakub at gcc dot gnu dot org
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