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Re: [patch, fortran] Use memcmp() for string comparison for constant-length kind=1 strings
- From: Janne Blomqvist <blomqvist dot janne at gmail dot com>
- To: Thomas Koenig <tkoenig at netcologne dot de>
- Cc: "fortran at gcc dot gnu dot org" <fortran at gcc dot gnu dot org>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 26 Mar 2013 23:53:27 +0200
- Subject: Re: [patch, fortran] Use memcmp() for string comparison for constant-length kind=1 strings
- References: <515082C3 dot 9070602 at netcologne dot de>
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