pidigits: ~10% performance win by using adds instead of shifts
pidigits: ~10% performance win by using adds instead of shifts

user time for pidigits -s -n=10000:
6.466s w/ adds
7.138s w/ shifts

R=rsc
CC=golang-dev
http://codereview.appspot.com/1021041

nightlyone/golang,bdwalton/debian-golang,nightlyone/golang,tianon/debian-golang,bdwalton/debian-golang,dsriram/golang,dsriram/golang,bdwalton/debian-golang,gnanderson/go,tianon/debian-golang,ssrl/go,nightlyone/golang,gnanderson/go,h8liu/golang,tianon/debian-golang,dsriram/golang,apparentlymart/golang,bdwalton/debian-golang,tianon/debian-golang,tv42/old-go,apparentlymart/golang,h8liu/golang,tv42/old-go,pombredanne/go-deleteme,apparentlymart/golang,tianon/debian-golang,h8liu/golang,pombredanne/go-deleteme,tv42/old-go,tianon/debian-golang,bdwalton/debian-golang,ssrl/go,gnanderson/go,nightlyone/golang,pombredanne/go-deleteme,apparentlymart/golang,ssrl/go,tv42/old-go,ssrl/go,pombredanne/go-deleteme,nightlyone/golang,bdwalton/debian-golang,dsriram/golang,h8liu/golang,pombredanne/go-deleteme,dsriram/golang,h8liu/golang,apparentlymart/golang,dsriram/golang,tv42/old-go,pombredanne/go-deleteme,apparentlymart/golang,tianon/debian-golang,gnanderson/go,gnanderson/go,dsriram/golang,ssrl/go,nightlyone/golang,apparentlymart/golang,pombredanne/go-deleteme,ssrl/go,bdwalton/debian-golang,h8liu/golang,bdwalton/debian-golang,tianon/debian-golang,tv42/old-go,tv42/old-go,nightlyone/golang,h8liu/golang,gnanderson/go,ssrl/go,gnanderson/go