> This patch makes sure max count is used when merging two basic blocks.
>
> Bootstrapped and testing on-going.
>
> OK for trunk if test is ok?
>
> Thanks,
> Dehao
>
> gcc/ChangeLog:
> 2014-05-16 Dehao Chen <de...@google.com>
>
> * tree-cfg.c (gimple_merge_blocks): Updates bb count with max count.
>
> Index: gcc/tree-cfg.c
> ===================================================================
> --- gcc/tree-cfg.c (revision 210531)
> +++ gcc/tree-cfg.c (working copy)
> @@ -1877,6 +1877,15 @@ gimple_merge_blocks (basic_block a, basic_block b)
> }
> }
>
> + /* When merging two BBs, if their counts are different, the larger count
> + is selected as the new bb count. This is to handle inconsistent
> + profiles. */
> + if (a->count != b->count)
> + {
> + a->count = MAX (a->count, b->count);
> + a->frequency = MAX (a->frequency, b->frequency);
> + }
I would do max of frequency indpendently on count. I.e. just remove the
conditional around
the MAX operation.
This seems to make sense even w/o profile feedback.
Honza
