On 09/14/2016 01:10 PM, Segher Boessenkool wrote:
On Wed, Sep 14, 2016 at 11:52:02AM -0600, Jeff Law wrote:
Yea, it'll certainly do that and I can imagine a design which would have
that property. And there's other designs which benefit from spreading
across the register file as much as possible.
Which argues there needs to be a way to tune or disable the pass.
Yes, some targets want it, and some don't. It seems to me that targets
that use sched1 have much less benefit from regrename. Of course enabling
sched1 has its own problems.
I think that sched1 would decrease the benefit of reg renaming, but
wouldn't totally eliminate the desire to avoid anti dependencies created
by register allocation.
jeff
