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[Bug fortran/40766] this fortran program is too slow
- From: "jvdelisle at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 5 Dec 2009 06:29:16 -0000
- Subject: [Bug fortran/40766] this fortran program is too slow
- References: <bug-40766-15353@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #16 from jvdelisle at gcc dot gnu dot org 2009-12-05 06:29 -------
This is a glibc issue with software sin function. It does not use the FPU.
Just try with -m32. Changing n=50000
$ gfc -m64 untitled.f90
$ time ./a.out
-1781878.9
real 0m3.060s
user 0m3.050s
sys 0m0.003s
$ gfc -m32 untitled.f90
$ time ./a.out
-1781888.9
real 0m0.234s
user 0m0.231s
sys 0m0.004s
$
The situation is absolutely absurd. I opened a PR for this so long ago, I
don't remember the number.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40766