[patch, arm] Prefer LO_REG registers in regrename

[Richard Earnshaw]

On Thu, 2010-12-09 at 00:42 +0800, Yao Qi wrote:
> This patch is to implement to targethook preferred_rename_class, in
> order to prefer LO_REGS registers over GENERAL_REGS registers in Thumb-2.
> 
> EEMBC doesn't show speed improvements, but code size of some benchmarks
> in EEMBC is reduced by 0.1% ~ 0.2%.  Regression tested on '2010-11-30'
> trunk.  OK for mainline?
> 

This is OK.  However, I don't see any point in calling the default
version of this function when that's defined to just return NO_REGS.
Just do that directly yourself and save the overhead of another branch.

R.