Jump optimisation patches

[Michael P. Hayes]

Jeffrey A Law writes:
 > Don't you also need one in the conditional for this optimization:
 > 
 >          /* If branches are expensive, convert
 >                 if (foo) bar++;    to    bar += (foo != 0);
 >              and similarly for "bar--;"
 > 

I don't think so.  It appears that this optimisation is caught
by the more general test (circa line 1000 in jump.c) for targets
that don't have CC0.  The patches I submitted were to fix a problem
for those targets where an insn was moved into a place where
it clobbered something required by the following insn (usually
the contents of the CC register).