Hi,
> The patch simplifies usage of the profile_{count,probability} types.
>
> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>
> Ready to be installed?
The reason I intentionally did not add * and / to the original API was
to detect situations where values that should be
profile_count/profile_probability are stored into integers, since
previous code used integers for everything.
Having one to add apply_scale made him/her (mostly me :) to think if the
value is really just a fixed scale or it it should be better converted
to proper data type (count or probability).
I guess now we completed the conversion so risk of this creeping in is
relatively low and the code indeed looks better. It will make it bit
harder for me to backport jump threading profile updating fixes I plan
for 12.2 but it should not be hard.
> diff --git a/gcc/cfgloopmanip.cc b/gcc/cfgloopmanip.cc
> index b4357c03e86..a1ac1146445 100644
> --- a/gcc/cfgloopmanip.cc
> +++ b/gcc/cfgloopmanip.cc
> @@ -563,8 +563,7 @@ scale_loop_profile (class loop *loop, profile_probability
> p,
>
> /* Probability of exit must be 1/iterations. */
> count_delta = e->count ();
> - e->probability = profile_probability::always ()
> - .apply_scale (1, iteration_bound);
> + e->probability = profile_probability::always () / iteration_bound;
However this is kind of example of the problem.
iteration_bound is gcov_type so we can get overflow here.
I guess we want to downgrade iteration_bound since it is always either 0
or int.
> diff --git a/gcc/tree-switch-conversion.cc b/gcc/tree-switch-conversion.cc
> index e14b4e6c94a..cef26a9878e 100644
> --- a/gcc/tree-switch-conversion.cc
> +++ b/gcc/tree-switch-conversion.cc
> @@ -1782,7 +1782,7 @@ switch_decision_tree::analyze_switch_statement ()
> tree high = CASE_HIGH (elt);
>
> profile_probability p
> - = case_edge->probability.apply_scale (1, (intptr_t) (case_edge->aux));
> + = case_edge->probability / ((intptr_t) (case_edge->aux));
I think the switch ranges may be also in risk of overflow?
We could make operators to accept gcov_type or int64_t.
Thanks,
Honza
