During an LTO/PGO Firefox build one gets countless warnings:
warning: -fprefetch-loop-arrays is not supported with -Os
This happens because flag_prefetch_loop_arrays is always set during the
profile-use phase.
Fix by following the suggestion of Jakub and disable prefetching of
loop_arrays when optimizing for size.
Please apply if the patch looks OK.
Thanks.
2013-08-30 Markus Trippelsdorf <mar...@trippelsdorf.de>
* config/i386/i386.c (ix86_option_override_internal): Only
prefetch loop_arrays during profile_use when not optimizing for
size.
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index a8d70bc..f385db4 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -3952,7 +3952,7 @@ ix86_option_override_internal (bool main_args_p)
/* Enable sw prefetching at -O3 for CPUS that prefetching is helpful. */
if (flag_prefetch_loop_arrays < 0
&& HAVE_prefetch
- && (optimize >= 3 || flag_profile_use)
+ && (optimize >= 3 || (flag_profile_use && !optimize_size))
&& TARGET_SOFTWARE_PREFETCHING_BENEFICIAL)
flag_prefetch_loop_arrays = 1;
--
Markus
