On Mon, Nov 5, 2018 at 10:40 PM Jan Hubicka <hubi...@ucw.cz> wrote:
>
> diff --git a/gcc/profile-count.h b/gcc/profile-count.h
> index 4289bc5a004..2b5e3269250 100644
> --- a/gcc/profile-count.h
> +++ b/gcc/profile-count.h
> @@ -218,6 +218,11 @@ public:
> }
>
>
> + /* Return true if value is zero. */
> + bool never_p () const
> + {
> + return m_val == 0;
> + }
> /* Return true if value has been initialized. */
> bool initialized_p () const
> {
> @@ -288,9 +293,9 @@ public:
> }
> profile_probability operator+ (const profile_probability &other) const
> {
> - if (other == profile_probability::never ())
> + if (other.never_p ())
> return *this;
> - if (*this == profile_probability::never ())
> + if (this->never_p ())
>
> This is not correct change. If you add guessed 0 to precise 0,
> the result needs to be guessed 0 because we are no longer sure the code
> will not get executed. This is why all the checks here go explicitly
> to profile_probability::never.
Hmm, so precise 0 means the code can never get executed? I also noticed
that in predict.c there are lots of direct assignment of profile_count::zero as:
propagation_unlikely_bbs_forward (void)
{
//...
bb->count = profile_count::zero ();
//...
}
This generally promote profile_count::zero from lower precision to precise
precision, but function name/comment seems targeting unlikely executed
code, rather than never executed. Is this inconsistent?
Thanks,
bin
>
> Honza
