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* [Bug target/95458] New: Inline strncmp is *much* slower than glibc @ 2020-06-01 12:20 hjl.tools at gmail dot com 2020-07-16 20:54 ` [Bug target/95458] " aoliva at gcc dot gnu.org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: hjl.tools at gmail dot com @ 2020-06-01 12:20 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95458 Bug ID: 95458 Summary: Inline strncmp is *much* slower than glibc Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: hjl.tools at gmail dot com CC: crazylht at gmail dot com Depends on: 43052 Target Milestone: --- Similar to PR 43052, inline strncmp is *much* slower than glibc. PR 43052 was "fixed" by accident: commit 9b0f6f5e511ca512e4faeabc81d2fd3abad9b02f Author: Nick Clifton <nickc@redhat.com> Date: Fri Aug 12 16:26:11 2011 +0000 builtins.c (expand_builtin_memcmp): Do not use cmpstrnsi pattern. * builtins.c (expand_builtin_memcmp): Do not use cmpstrnsi pattern. * doc/md.texi (cmpstrn): Note that the comparison stops if both fetched bytes are zero. (cmpstr): Likewise. (cmpmem): Note that the comparison does not stop if both of the fetched bytes are zero. strncmp should be inlined only for -minline-all-stringops. Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43052 [Bug 43052] [4.9/5/6 Regression] Inline memcmp is *much* slower than glibc's, no longer expanded inline ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/95458] Inline strncmp is *much* slower than glibc 2020-06-01 12:20 [Bug target/95458] New: Inline strncmp is *much* slower than glibc hjl.tools at gmail dot com @ 2020-07-16 20:54 ` aoliva at gcc dot gnu.org 2020-08-19 13:22 ` hjl.tools at gmail dot com ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: aoliva at gcc dot gnu.org @ 2020-07-16 20:54 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95458 Alexandre Oliva <aoliva at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |aoliva at gcc dot gnu.org --- Comment #1 from Alexandre Oliva <aoliva at gcc dot gnu.org> --- https://gcc.gnu.org/legacy-ml/gcc-patches/2019-09/msg00701.html seems relevant ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/95458] Inline strncmp is *much* slower than glibc 2020-06-01 12:20 [Bug target/95458] New: Inline strncmp is *much* slower than glibc hjl.tools at gmail dot com 2020-07-16 20:54 ` [Bug target/95458] " aoliva at gcc dot gnu.org @ 2020-08-19 13:22 ` hjl.tools at gmail dot com 2020-10-26 11:17 ` cvs-commit at gcc dot gnu.org 2020-10-26 11:17 ` hjl.tools at gmail dot com 3 siblings, 0 replies; 5+ messages in thread From: hjl.tools at gmail dot com @ 2020-08-19 13:22 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95458 H.J. Lu <hjl.tools at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Target Milestone|--- |11.0 Status|UNCONFIRMED |NEW Last reconfirmed| |2020-08-19 --- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to Alexandre Oliva from comment #1) > https://gcc.gnu.org/legacy-ml/gcc-patches/2019-09/msg00701.html seems > relevant We can improve inlined strncmp. But the library version still is much faster. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/95458] Inline strncmp is *much* slower than glibc 2020-06-01 12:20 [Bug target/95458] New: Inline strncmp is *much* slower than glibc hjl.tools at gmail dot com 2020-07-16 20:54 ` [Bug target/95458] " aoliva at gcc dot gnu.org 2020-08-19 13:22 ` hjl.tools at gmail dot com @ 2020-10-26 11:17 ` cvs-commit at gcc dot gnu.org 2020-10-26 11:17 ` hjl.tools at gmail dot com 3 siblings, 0 replies; 5+ messages in thread From: cvs-commit at gcc dot gnu.org @ 2020-10-26 11:17 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95458 --- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by H.J. Lu <hjl@gcc.gnu.org>: https://gcc.gnu.org/g:4052c05e5b30fee0fb95a51e74e12a56dce29491 commit r11-4380-g4052c05e5b30fee0fb95a51e74e12a56dce29491 Author: H.J. Lu <hjl.tools@gmail.com> Date: Wed Jul 15 10:34:54 2020 -0700 x86: Inline strncmp only with -minline-all-stringops Expand strncmp to "repz cmpsb" only with -minline-all-stringops since "repz cmpsb" can be much slower than strncmp function implemented with vector instructions, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43052 gcc/ PR target/95458 * config/i386/i386-expand.c (ix86_expand_cmpstrn_or_cmpmem): Return false for -mno-inline-all-stringops. gcc/testsuite/ PR target/95458 * gcc.target/i386/pr95458-1.c: New test. * gcc.target/i386/pr95458-2.c: Likewise. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/95458] Inline strncmp is *much* slower than glibc 2020-06-01 12:20 [Bug target/95458] New: Inline strncmp is *much* slower than glibc hjl.tools at gmail dot com ` (2 preceding siblings ...) 2020-10-26 11:17 ` cvs-commit at gcc dot gnu.org @ 2020-10-26 11:17 ` hjl.tools at gmail dot com 3 siblings, 0 replies; 5+ messages in thread From: hjl.tools at gmail dot com @ 2020-10-26 11:17 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95458 H.J. Lu <hjl.tools at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |FIXED Status|NEW |RESOLVED --- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> --- Fixed for GCC 11. ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-10-26 11:17 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-06-01 12:20 [Bug target/95458] New: Inline strncmp is *much* slower than glibc hjl.tools at gmail dot com 2020-07-16 20:54 ` [Bug target/95458] " aoliva at gcc dot gnu.org 2020-08-19 13:22 ` hjl.tools at gmail dot com 2020-10-26 11:17 ` cvs-commit at gcc dot gnu.org 2020-10-26 11:17 ` hjl.tools at gmail dot com
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