[PATCH] Fix PR 61225

[Jeff Law]

On 12/04/14 13:57, Segher Boessenkool wrote:
>
> So combine tries to combine 6+7+8; the RTL it comes up with is a parallel
> of the memory decrement (without cc clobber, but that is fine), and setting
> r88 to the mem minus one.  There is no such pattern in the target, and
> combine cannot break the parallel into two sets (because the first modifies
> the mem used by the second), so 6+7+8 doesn't combine.
>
> Adding a bridge pattern in the target would work; or you can enhance combine
> so it can break up this parallel correctly.
I think myself or someone suggested a bridge pattern in the past, but I 
can't find it, perhaps it was one of the other threads WRT limitations 
of the combiner.

Zhenqiang, can you look at what happens if you provide a pattern for 
6+7+8 (probably via a define_and_split)?

Jeff