[patch] struct resources: remove unch_memory member

[Eric Botcazou]

> This unch_memory in struct resources is a left-over from
> RTX_UNCHANGING_P, but it looks like the change-over to MEM_READONLY_P
> was done incorrectly: The resource_conflicts_p code now reports
> conflicts for insns reading readonly memory and insns reading "normal"
> memory or no memory at all.

Does it really?  One would need to have a SET of a MEM_READONLY_P MEM and this 
isn't supposed to happen (unlike with RTX_UNCHANGING_P).  That being said, the 
patch is a good cleanup.

> Spotted by checking why reorg.c failed to fill some slots that my
> sched-deps based delay slot scheduler managed to fill.

I've been in the business lately so I'm interested in all things reorg.c. :-)

> Bootstrapped&tested on sparc64-unknown-linux-gnu. OK for trunk?

Fine with me.

-- 
Eric Botcazou