Paul Eggert wrote:
> Attached are some proposed patches which should improve the performance
> of grep -P when applied to binary files, among other things.  I have
> some other ideas for boosting performance further but thought I'd
> publish these first.

I pushed those patches, along with the attached further patches to fix 
up some porting glitches and bugs I encountered in subsequent testing. 
I plan to follow up soon on Bug#18454 with more performance-related 
patches in this area.