> This patch uses direct computation (instead of indirect minus
> computation) to calculate fallthrough edge's count and frequency. This
> is less error-prone when the profile is inconsistent (e.g. all succ
> edge counts sums larger than bb count).
>
> Bootstrapped and regression test on-going.
>
> OK for trunk if test pass?
OK,
thanks!
Honza
>
> Thanks,
> Dehao
>
> gcc/ChangeLog:
> 2014-05-16 Dehao Chen <de...@google.com>
>
> * cfghooks.c (make_forwarder_block): Use direct computation to
> get fall-through edge's count and frequency.
>
> Index: gcc/cfghooks.c
> ===================================================================
> --- gcc/cfghooks.c (revision 210518)
> +++ gcc/cfghooks.c (working copy)
> @@ -833,6 +833,9 @@ make_forwarder_block (basic_block bb, bool (*redir
>
> fallthru = split_block_after_labels (bb);
> dummy = fallthru->src;
> + dummy->count = 0;
> + dummy->frequency = 0;
> + fallthru->count = 0;
> bb = fallthru->dest;
>
> /* Redirect back edges we want to keep. */
> @@ -842,20 +845,13 @@ make_forwarder_block (basic_block bb, bool (*redir
>
> if (redirect_edge_p (e))
> {
> + dummy->frequency += EDGE_FREQUENCY (e);
> + dummy->count += e->count;
> + fallthru->count += e->count;
> ei_next (&ei);
> continue;
> }
>
> - dummy->frequency -= EDGE_FREQUENCY (e);
> - dummy->count -= e->count;
> - if (dummy->frequency < 0)
> - dummy->frequency = 0;
> - if (dummy->count < 0)
> - dummy->count = 0;
> - fallthru->count -= e->count;
> - if (fallthru->count < 0)
> - fallthru->count = 0;
> -
> e_src = e->src;
> jump = redirect_edge_and_branch_force (e, bb);
> if (jump != NULL)
