target-ppc: optimize cmp translation

We know that only one bit (in addition to SO) is going to be set in
the condition register, so do two movconds instead of three setconds,
three shifts and two ORs.

For ppc64-linux-user, the code size reduction is around 5% and the
performance improvement slightly less than 10%.  For softmmu, the
improvement is around 5%.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
1 file changed