PATH: removing quadratic complexity strstr, strcasestr and strcasestr-nonascii
Mike Frysinger
vapier@gentoo.org
Tue Jul 3 20:34:00 GMT 2012
On Monday 02 July 2012 15:07:54 Maxim Kuvyrkov wrote:
> On 30/06/2012, at 3:31 AM, Dmitrieva Liubov wrote:
> > This patch removes SSE42 strstr, strcasestr and strcasestr-nonascii
> > because these SSE42 algorithms have quadratic complexity.
> >
> > The patch was checked on x86_64 and x86_32.
> >
> > ChangeLog:
> >
> > 2012-06-29 Liubov Dmitrieva <liubov.dmitrieva@gmail.com>
> >
> > * sysdeps/i386/i686/multiarch/Makefile: Update
> > Remove strstr, strcasesrt, strcasestr-nonascii
> > SSE42 optimizations since algos have quadratic complexity
> > * sysdeps/i386/i686/multiarch/strcasestr-c.c: Delete
> > * sysdeps/i386/i686/multiarch/strcasestr-nonascii.c: Delete
> > * sysdeps/i386/i686/multiarch/strstr-c.c: Delete
> > * sysdeps/i386/i686/multiarch/strstr.c: Delete
> >
> > * sysdeps/x86_64/multiarch/Makefile: Update
> > Remove strstr, strcasesrt, strcasestr-nonascii
> > SSE42 optimizations since algos have quadratic complexity
> > * sysdeps/x86_64/multiarch/strcasestr-c.c: Delete
> > * sysdeps/x86_64/multiarch/strcasestr-nonascii.c: Delete
> > * sysdeps/x86_64/multiarch/strstr-c.c: Delete
> > * sysdeps/x86_64/multiarch/strstr.c: Delete
>
> While I don't have strong opinion about this patch, it doesn't seem right
> to throw away a perfectly good SSE42 implementation that outperforms the
> generic one by a factor of 2 on small needles.
+1
-mike
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