http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58250
Bug ID: 58250 Summary: -fprofile-use causes: "warning: -fprefetch-loop-arrays is not supported with -Os" Product: gcc Version: 4.9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: gcov-profile Assignee: unassigned at gcc dot gnu.org Reporter: markus at trippelsdorf dot de Just noticed this issue during a PGO/LTO Firefox build. During the -fprofile-use phase I always get the following warning: warning: -fprefetch-loop-arrays is not supported with -Os [enabled by default] This is caused by rev.193135: /* Enable sw prefetching at -O3 for CPUS that prefetching is helpful. */ if (flag_prefetch_loop_arrays < 0 && HAVE_prefetch - && optimize >= 3 + && (optimize >= 3 || flag_profile_use) && TARGET_SOFTWARE_PREFETCHING_BENEFICIAL) flag_prefetch_loop_arrays = 1; Does the following patch look OK? diff --git a/gcc/toplev.c b/gcc/toplev.c index 53f53fd..9955ed4 100644 --- a/gcc/toplev.c +++ b/gcc/toplev.c @@ -1506,7 +1506,7 @@ process_options (void) /* This combination of options isn't handled for i386 targets and doesn't make much sense anyway, so don't allow it. */ - if (flag_prefetch_loop_arrays > 0 && optimize_size) + if (flag_prefetch_loop_arrays > 0 && optimize_size && !flag_profile_use) { warning (0, "-fprefetch-loop-arrays is not supported with -Os"); flag_prefetch_loop_arrays = 0;