> Note we only really see the effect if we make sure that gcc
> isn't emitting its "special" memcmp: that's why the -fno-builtin-memcmp
> is SO important on gcc builds!

I'd rather infer the opposite: given how GCC generates code, this patch
is not worthwhile. Given that it actually slows down Python in the
default system configuration, I'm -1 on applying it. This is really not
a route we should take; it leads to maintenance pain.