[Patch, i386]: Set avx128 preferred vector mode for btver2

Kumar, Venkataramanan Venkataramanan.Kumar@amd.com
Wed Jan 9 05:06:00 GMT 2013

Hi Maintainers,

Please fine below patch that sets preferred vectorization mode for btver2  as avx128. 

We tested some benchmarks and found that enabling 128-bit AVX instruction generation by the  auto vectorizer performs better than 
default 256-bit AVX.

Completed bootstrap and make -k check passes.

Ok for trunk?


2013-01-09  Venkataramanan Kumar  <venkataramanan.kumar@amd.com>

       * config/i386/i386.c (initial_ix86_tune_features): Set up
       X86_TUNE_AVX128_OPTIMAL for m_BTVER2.

Index: i386.c
--- i386.c      (revision 194833)
+++ i386.c      (working copy)
@@ -2014,7 +2014,7 @@

   /* X86_TUNE_AVX128_OPTIMAL: Enable 128-bit AVX instruction generation for
      the auto-vectorizer.  */
-  m_BDVER,
+  m_BDVER | m_BTVER2,

   /* X86_TUNE_REASSOC_INT_TO_PARALLEL: Try to produce parallel computations
      during reassociation of integer computation.  */


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