Thank you very much Mr. Naishlos. -Balaji V. Iyer.
-----Original Message----- From: Dorit Naishlos [mailto:[EMAIL PROTECTED] Sent: Monday, November 21, 2005 3:47 PM To: Balaji V. Iyer Cc: gcc@gcc.gnu.org Subject: Re: Vectorizer in GCC 4.0 > Hello Everyone, > I am interested in knowing more about the vectorizer in GCC. Does > anyone have or know of any statistics about the percentage of loops > that can be vectorized in some benchmarks like MediaBench, SPEC2K and > so forth? > I have some old Spec2000 statistics, from around June, using autovect-branch: 226 loops where vectorized on powerpc970 out of 4506 inner-most single-entry/exit single-bb countable loops. (note that on powerpc970 only single-precision fp benchmarks can be vectorized, and most of Spec-fp operates on doubles). The more interesting question is whether we get any performance impact with vectorization. There's one Spec-int benchmark for which vectorization actually has an impact on the performance of the entire application - gzip is improved by 8% due to vectorization. Haven't tried MediaBench yet; I'd be curious to see the results if anyone tries it out. We vectorize 4 loops in linpack, getting ~36% improvement on the entire benchmark. Additional numbers on other benchmarks will be available in the near future. Also see: - Vectorizing Hilaram: http://gcc.gnu.org/ml/gcc/2005-10/msg01044.html - Vectorizing libgfortran: http://gcc.gnu.org/ml/gcc-bugs/2005-11/msg01722.html dorit > Thanking You, > > Yours Sincerely, > > Balaji V. Iyer. >
