> If -fprofile-use is specified, but no .gcda file is found, reset all
> the flags back to the values they would have had if -fprofile-use was
> not specified. Since the code path where -fprofile-use is on and
> .gcda files are not found is not a well tested pass, this will
> increase the robustness of FDO. Further, in the event an ICE is found
> when doing FDO, this allows users to delete .gcda files as a work
> around without having to implement complex modifications to the build
> system. To ensure the testsuite still passes (and is relevant), some
> tests which used -fprofile-use but had no .gcda file had to be moved
> so that they would have a .gcda file generated. This also involved
> adding a main to these unit tests.
>
> Bootstrapped and regtested on x86_64. Ok for trunk?
>
> 2009-09-29 Neil Vachharajani <nvach...@google.com>
> * coverage.c (read_counts_file): Disable profile use if no .gcda
> file is found.
> * opts.c (common_handle_option): Call set_profile_use instead of
> directly setting parameters in -fprofile-use.
> (set_profile_use): New function.
> * opts.h (set_profile_use): New function.
> * testsuite/g++.dg/tree-ssa/dom-invalid.C: Moved to
> testsuite/g++.dg/tree-prof.
> * testsuite/g++.dg/tree-prof/dom-invalid.C: See above.
> * testsuite/gcc.dg/pr26570.c: Moved to
> testsuite/gcc.dg/tree-prof.
> * testsuite/gcc.dg/tree-prof/pr26570.c: See above. main added.
> * testsuite/gcc.dg/pr32773.c: Moved to
> testsuite/gcc.dg/tree-prof.
> * testsuite/gcc.dg/tree-prof/pr32773.c: See above. main added.
>
> +
> +/* Set FLAG_PROFILE_USE and dependent flags based on VALUE. This
> + function is used to handle the -f(no)profile-use option as well as
> + to reset flags if a .gcda file is not found. */
> +
> +void
> +set_profile_use (bool value, bool force)
> +{
> + flag_profile_use = value;
> + if (!flag_branch_probabilities_set || force)
> + flag_branch_probabilities = value;
> + if (!flag_profile_values_set || force)
> + flag_profile_values = value;
> + if (!flag_unroll_loops_set)
> + flag_unroll_loops = value;
> + if (!flag_peel_loops_set)
> + flag_peel_loops = value;
> + if (!flag_tracer_set)
> + flag_tracer = value;
> + if (!flag_value_profile_transformations_set || force)
> + flag_value_profile_transformations = value;
> + if (!flag_inline_functions_set)
> + flag_inline_functions = value;
> + if (!flag_ipa_cp_set)
> + flag_ipa_cp = value;
> + if (!flag_ipa_cp_clone_set)
> + {
> + if (!flag_ipa_cp_set || flag_ipa_cp)
> + flag_ipa_cp_clone = value;
> + }
> + if (!flag_predictive_commoning_set)
> + flag_predictive_commoning = value;
> + if (!flag_unswitch_loops_set)
> + flag_unswitch_loops = value;
> + if (!flag_gcse_after_reload_set)
> + flag_gcse_after_reload = value;
> +}
It seems to make sense to disable profile feedback when GCDA is missing.
However I wonder if we can't
figure out before finishing of parsing of flags?
Machine descriptions may want to alter options depending on profile-use so this
approach seems fragile.
Honza
