Comparing Linux C and C++ Compilers: Benchmarks and Analysis

[Richard Guenther]

On Sat, 18 Sep 2004 13:10:38 -0400, Scott Robert Ladd
<coyote@coyotegulch.com> wrote:
> Hello,
> 
> I've posted a comparison of recent GCC versions (3.3, 3.4, and the
> coming 4.0) with Intel C++ 8.1, including several benchmarks and
> "state-of-the-product" reviews. You can find the article at:
> 
>      http://www.coyotegulch.com/reviews/linux_compilers/
> 
> The above article replaces an older piece I published in late 2002. This
> new comparison marks what I hope will be an ongoing series that tracks
> the quality of Linux compilers.

You may want to check gcc 4.0s auto-vectorizing capabilities by using
-ftree-vectorize.  I believe Intel compiler does this by default with your
optimization settings, and also unrolls loops where profitable (-funroll-loops
for all gcc versions).  While I personally do not have success with
auto-vectorizing (neither with Intel nor with gcc), loop unrolling
shows very positive effects on my numerical codes.

Richard.