[tree-ssa] Speedup alias analysis [patch]

[law@redhat.com]

In message <20030623213514.GA26675@tornado.toronto.redhat.com>, Diego Novillo w
rites:
 >This patch re-implements alias analysis to prevent the huge
 >compile time and memory consumption problems we were experiencing
 >in heavily aliased code.
[ ... ]
So do you have any performance comparisons you'd like to share with the
rest of us :-)

Jeff