This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug fortran/30388] gfortran42 is slower than g77 3.4 about 10%
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 6 Jan 2007 10:17:02 -0000
- Subject: [Bug fortran/30388] gfortran42 is slower than g77 3.4 about 10%
- References: <bug-30388-11045@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from rguenth at gcc dot gnu dot org 2007-01-06 10:17 -------
Well, it all boils down to differences in induction variable choices. The
choice made by 3.4 (for i686) doesn't look too good to me compared to 4.1.2
here.
4.1: MFLOPS: 990.4130 time(s): 28.10176
3.4: MFLOPS: 449.016235 time(s): 59.8477402
(-O2 -ffast-math -funroll-loops -fomit-frame-pointer)
The predcomm branch should be able to do a lot better here.
With SSE math I get
4.1: MFLOPS: 954.2382 time(s): 31.46597
3.4: MFLOPS: 467.92215 time(s): 59.1876984
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rakdver at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30388