On 09/14/2016 07:55 AM, Segher Boessenkool wrote:
On Wed, Sep 14, 2016 at 03:08:21PM +0200, Bernd Schmidt wrote:
On 09/14/2016 03:04 PM, Segher Boessenkool wrote:
Then rs6000 (and many other ports probably) will just turn it off again.
It is actively harmful.
The data that was posted showed a code size decrease on a number of
targets. I'm really not sure where this irrational hate for regrename
comes from.
It increases the number of active, "young" registers per thread.
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.
Jeff
