Gives ~20% boost for Crypto benchmark on A9.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org//7148018
Patch from Martyn Capewell <m.m.capewell@googlemail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8381 ce2b1a6d-e550-0410-aec6-3dcde31c8c00