[patch, fortran] Use memcmp() for string comparison for constant-length kind=1 strings

[Ondřej Bílka]

On Tue, Mar 26, 2013 at 11:53:27PM +0200, Janne Blomqvist wrote:
> On Mon, Mar 25, 2013 at 7:00 PM, Thomas Koenig <tkoenig@netcologne.de> wrote:
> > Hello world,
> >
> > this patch uses memcpy() directly when comparing two kind=1 strings of
> > equal and constant lengths.  The test case modification depends
> > on the previous patch at
> >
Could you omit of equal lengths part? Do memcmp with minimum of lengths
and if not equal call compare_string for suffixes.

> > http://gcc.gnu.org/ml/gcc-patches/2013-03/msg00996.html
> >
> > for setting the string lengths for substrings.
> >
> > Regression-tested.  No extra test case because the original test
> > cases have to be modified to avoid failure, and test the new
> > feature.  OK for trunk after committing the patch above?
> >
> > 2013-03-25  Thomas Koenig  <tkoenig@gcc.gnu.org>
> >
> >         * trans-expr.c (build_memcmp_call):  New function.
> >         (gfc_build_compare_string):  If the kind=1 strings to be
> >         compared have constant and equal lengths, use
> >         memcmp().
> >
> > 2013-03-25  Thomas Koenig  <tkoenig@gcc.gnu.org>
> >
> >         * gfortran.dg/character_comparison_3.f90:  Adjust for use of memcmp
> >         for constant and equal string lengths.
> >         * gfortran.dg/character_comparison_5.f90:  Likewise.
> 
> Ok. I think the same optimization could be done for kind=4 strings as
> well, but nobody probably uses those anyway..
> 
> 
> -- 
> Janne Blomqvist