Set fast unaligned load flag for new Intel microarchitecture

I have small patch for new Intel Silvermont machines.

http://newsroom.intel.com/community/intel_newsroom/blog/2013/05/06/intel-launches-low-power-high-performance-silvermont-microarchitecture

I checked this on my machine and see that strcpy, ... unaligned
versions are faster than ssse3 versions.

diff --git a/ChangeLog b/ChangeLog
index 77ac803..86d98f7 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-06-14  Liubov Dmitrieva  <liubov.dmitrieva@intel.com>
+
+       * sysdeps/x86_64/multiarch/init-arch.c (__init_cpu_features):
+       Set bit_Fast_Unaligned_Load for Intel Silvermont architecture.
+
 2013-06-14  Siddhesh Poyarekar  <siddhesh@redhat.com>
            H.J. Lu  <hjl.tools@gmail.com>
 

diff --git a/sysdeps/x86_64/multiarch/init-arch.c b/sysdeps/x86_64/multiarch/init-arch.c
index 7daaf46..9524aee 100644 (file)
--- a/sysdeps/x86_64/multiarch/init-arch.c
+++ b/sysdeps/x86_64/multiarch/init-arch.c
@@ -78,6 +78,13 @@ __init_cpu_features (void)
              __cpu_features.feature[index_Slow_BSF] |= bit_Slow_BSF;
              break;
 
+           case 0x37:
+             /* Unaligned load versions are faster than SSSE3
+                on Silvermont.  */
+             __cpu_features.feature[index_Fast_Unaligned_Load]
+               |= bit_Fast_Unaligned_Load;
+             break;
+
            default:
              /* Unknown family 0x06 processors.  Assuming this is one
                 of Core i3/i5/i7 processors if AVX is available.  */