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

[Janne Blomqvist]

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
>
> 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