ea9b26bc94
on i486's (and probably i386's), but it has had very little effect since gcc-2.7 or gcc-2.95. With gcc-3.3, it gave a small pessimization for at least i386's, athlon-xp's and pentium4's, a small optimization (I think) for pentium1's, and made no difference for i386's. (movzbl is best for all the later processors, and the micro-optimization was to stop it being used on i486's.)