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 <ni...@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
