http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43052
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target|i486-linux-gnu |x86_64-*-*, i?86-*-*
CC| |rth at gcc dot gnu.org,
| |uros at gcc dot gnu.org
Target Milestone|--- |4.7.0
Summary|Inline memcmp is *much* |[4.7 Regression] Inline
|slower than glibc's |memcmp is *much* slower
| |than glibc's, no longer
| |expanded inline
--- Comment #16 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-24
10:56:00 UTC ---
Since
2011-08-12 Nick Clifton <[email protected]>
* 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.
we no longer expand memcmp inline as x86 does not have a cmpmemsi pattern.
Testcase:
int foo(char *s, char *q)
{
return memcmp (s, q, 4);
}
the 1-size case is folded to *s == *q.
This is now a regression, we have to do _something_ about it for 4.7,
at least for constant small sizes.
