[tree-ssa] Fix gcc.dg/tree-ssa/20030530-2.c

[law@redhat.com]

In message <1055362533.824.77.camel@frodo.toronto.redhat.com>, Diego Novillo wr
ites:
 >On Wed, 2003-06-11 at 15:19, law@redhat.com wrote:
 >
 >>  >Heck, if we only have to deal with SSA_NAMEs, which are unique (right?), 
 >we
 >>  >can just sort by address.
 >> Or their version #.    Either way it's a simple comparison routine.
 >> 
 >Oh, so you just want deterministic access.  I thought you wanted to
 >distinguish which VUSES where for which operand.  In that case, sorting
 >by VAR_DECL address might be better because we can insert them sorted as
 >we build the voperands.
 >
 >If you sort by SSA version number, then you have to build the voperand
 >array first and wait until after the SSA pass to re-sort each varray.
 >
 >Either way is fine with me, really.
I just did some experiments -- it doesn't appear it's worth the effort
to sort the voperands.  ie, we're not missing significant opportunities
to remove redundant loads due to differences in vuse orderings.

Consider this issue tabled until further notice.  Now to try and figure
out what was next on my stack...  Hmmm.

Jeff