[tree-ssa] folding fix 2

[law@redhat.com]

In message <20031221101036.GE17542@kam.mff.cuni.cz>, Jan Hubicka writes:
 >Hi,
 >fold folds a==b into different copy of a==b that waste memory and can
 >cause some optimizations thesting whether something simplified to loop.
 >I also have sanity checking veirfying that statements don't fold that
 >needs this.
 >OK?
 >Bootstrapped/regteste i686-pc-gnu-linux.
 >
 >Honza
 >
 >2003-12-21  Jan Hubicka  <jh@suse.cz>
 >	* fold-const.c (fold): Do not rebuild comparison when nothing
 >	changed.
This is fine.   Please install this patch.

Thanks,
jeff