Many supported cores use the AUTOPREFETCHER_WEAK setting which tries to order...

Many supported cores use the AUTOPREFETCHER_WEAK setting which tries
to order loads and stores to improve streaming performance.  Since significant
gains were reported in http://patchwork.ozlabs.org/patch/534469/ it seems
like a good idea to enable this setting too for -mcpu=generic.  Since the
weak model only keeps the order if it doesn't make the schedule worse, it
should not impact performance adversely on cores that don't show a gain.

    gcc/
        * config/aarch64/aarch64.c (generic_tunings): Update prefetch model.

From-SVN: r247610

gcc/ChangeLog

 2017-05-04  Wilco Dijkstra  <wdijkstr@arm.com>
 
+	* config/aarch64/aarch64.c (generic_tunings): Update prefetch model.
+
+2017-05-04  Wilco Dijkstra  <wdijkstr@arm.com>
+
 	* config/aarch64/aarch64.c (cortexa35_tunings): Set jump alignment to 4.
 	(cortexa53_tunings): Likewise.
 	(cortexa57_tunings): Likewise.

gcc/config/aarch64/aarch64.c

@@ -547,7 +547,7 @@ static const struct tune_params generic_tunings =
   2,	/* min_div_recip_mul_df.  */
   0,	/* max_case_values.  */
   0,	/* cache_line_size.  */
-  tune_params::AUTOPREFETCHER_OFF,	/* autoprefetcher_model.  */
+  tune_params::AUTOPREFETCHER_WEAK,	/* autoprefetcher_model.  */
   (AARCH64_EXTRA_TUNE_NONE)	/* tune_flags.  */
 };