2010-07-02 Christian Borntraeger <borntraeger@de.ibm.com>

	* config/s390/s390.c (override_options): Adopt prefetching
	at -O3 to handle flag_prefetch_loop_arrays as a tristate.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@161709 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 84ec105..a397936 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2010-07-02  Christian Borntraeger  <borntraeger@de.ibm.com>
+
+       * config/s390/s390.c (override_options): Adopt prefetching
+       at -O3 to handle flag_prefetch_loop_arrays as a tristate.
+
 2010-07-02  Jan Hubicka  <jh@suse.cz>
 
        * df-problems.c (df_kill_notes): Do not collect dead  notes.

diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 7ff8cb8..652a69c 100644 (file)
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -1675,8 +1675,9 @@ override_options (void)
     set_param_value ("simultaneous-prefetches", 6);
 
   /* This cannot reside in optimization_options since HAVE_prefetch
-     requires the arch flags to be evaluated already.  */
-  if (HAVE_prefetch && optimize >= 3)
+     requires the arch flags to be evaluated already.  Since prefetching
+     is beneficial on s390, we enable it if available.  */
+  if (flag_prefetch_loop_arrays < 0 && HAVE_prefetch && optimize >= 3)
     flag_prefetch_loop_arrays = 1;
 }