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From: "ysrumyan at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug lto/66752] spec2000 255.vortex performance compiled with GCC is ~20% lower than with CLANG Date: Fri, 10 Jul 2015 16:21:00 -0000 [thread overview] Message-ID: <bug-66752-4-9UXQdJ7N5Y@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-66752-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66752 Yuri Rumyantsev <ysrumyan at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |ysrumyan at gmail dot com --- Comment #3 from Yuri Rumyantsev <ysrumyan at gmail dot com> --- We found out simple reproducer for this issue which is attached. The problem is redundant test in loop: for (i = -1, flag = 1; ++i < N && flag;) if (a[i] == b) < set 'flag' to 0 & do something> It is clear that test 'flag==1' can be deleted since there is the only place where it is set up to zero (then-part). Note that clang deletes it.
next prev parent reply other threads:[~2015-07-10 16:21 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-07-03 11:45 [Bug lto/66752] New: " evstupac at gmail dot com 2015-07-03 12:01 ` [Bug lto/66752] " rguenth at gcc dot gnu.org 2015-07-03 13:12 ` evstupac at gmail dot com 2015-07-10 16:21 ` ysrumyan at gmail dot com [this message] 2015-07-10 16:27 ` ysrumyan at gmail dot com 2015-07-10 16:35 ` pinskia at gcc dot gnu.org 2015-07-14 6:28 ` law at redhat dot com 2015-07-23 19:40 ` law at redhat dot com 2015-07-23 20:42 ` law at gcc dot gnu.org 2015-07-23 20:49 ` law at redhat dot com 2015-07-24 8:23 ` rguenth at gcc dot gnu.org 2015-07-25 5:46 ` law at gcc dot gnu.org 2015-07-29 14:52 ` law at redhat dot com 2015-07-31 21:05 ` law at redhat dot com 2015-08-27 16:05 ` law at redhat dot com 2015-08-28 16:25 ` law at redhat dot com
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