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From: "guojiufu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/59371] [9/10/11/12 Regression] Performance regression in GCC 4.8/9/10/11/12 and later versions. Date: Mon, 17 May 2021 03:11:44 +0000 [thread overview] Message-ID: <bug-59371-4-sacK32yOyZ@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-59371-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59371 --- Comment #28 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> --- If change code as below, 'i' is not starting from '0', and 'compare code' is '!=' then wrap/overflow on 'i' may happen, and optimizations (e.g. vectorization) are not applied. The below patch is trying to optimize this kind of loop. https://gcc.gnu.org/pipermail/gcc-patches/2021-May/570424.html int foo (int *p, unsigned short u_n, unsigned short i) { int x = 0; for (; i != u_n; i++) { x = x + p[i]; } return x; }
next prev parent reply other threads:[~2021-05-17 3:11 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-12-02 17:59 [Bug target/59371] New: Performance regression in GCC 4.8 " sje at gcc dot gnu.org 2013-12-03 9:37 ` [Bug target/59371] [4.8/4.9 Regression] " rguenth at gcc dot gnu.org 2013-12-03 16:42 ` sje at gcc dot gnu.org 2013-12-03 23:10 ` pinskia at gcc dot gnu.org 2013-12-04 1:49 ` macro@linux-mips.org 2013-12-04 1:52 ` pinskia at gcc dot gnu.org 2013-12-05 11:12 ` rguenth at gcc dot gnu.org 2013-12-05 23:43 ` macro@linux-mips.org 2013-12-17 10:33 ` jakub at gcc dot gnu.org 2013-12-19 15:37 ` rguenth at gcc dot gnu.org 2014-01-09 20:40 ` macro@linux-mips.org 2014-05-22 9:07 ` [Bug target/59371] [4.8/4.9/4.10 " rguenth at gcc dot gnu.org 2014-12-19 13:34 ` [Bug target/59371] [4.8/4.9/5 " jakub at gcc dot gnu.org 2015-03-13 20:18 ` sje at gcc dot gnu.org 2015-06-23 8:28 ` [Bug target/59371] [4.8/4.9/5/6 " rguenth at gcc dot gnu.org 2015-06-26 20:02 ` [Bug target/59371] [4.9/5/6 " jakub at gcc dot gnu.org 2015-06-26 20:32 ` jakub at gcc dot gnu.org 2021-05-14 9:47 ` [Bug target/59371] [9/10/11/12 Regression] Performance regression in GCC 4.8/9/10/11/12 " jakub at gcc dot gnu.org 2021-05-17 2:57 ` guojiufu at gcc dot gnu.org 2021-05-17 3:11 ` guojiufu at gcc dot gnu.org [this message] 2021-06-01 8:06 ` rguenth at gcc dot gnu.org 2022-05-27 9:35 ` [Bug target/59371] [10/11/12/13 " rguenth at gcc dot gnu.org 2022-06-28 10:30 ` jakub at gcc dot gnu.org 2023-07-07 10:30 ` [Bug target/59371] [11/12/13/14 " rguenth at gcc dot gnu.org
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