USE patch vs the PA

[Jeffrey A Law]

Well, after hacking the alias code a little, tomcatv with the
simplify_giv_expr patch (aka USE patch) now runs slightly faster
than tomcatv without the USE patch on my PA (as opposed to about
10% slower!)

There were basically three problems with the alias code.  I'll write
them up in more detail later this weekend.

  * Didn't handle autoincrement addressing.  It just punted.
  autoincrement addresses can be treated just like a set of the
  base value to itself plus a small constant.

  * find_base_value didn't do a good enough job when given the
  sum of two pseudos.

  * find_base_value (psuedo) would return the pseudo instead of
  the base value of the pseudo.


  	    
I'm going to do some more benchmarking, but hopefully we've solved
the mystery!




--
Jeff Law (law@cygnus.com)
Cygnus Solutions		EGCS GNU Compiler System
http://www.cygnus.com		http://www.cygnus.com/egcs