midRTL: midRTL generation

[law@redhat.com]

 In message <20020124163441.GD29296@atrey.karlin.mff.cuni.cz>, Jan Hubicka 
write
s:
 > This will avoid need for about 1000 expanders in midrtl.md
Think out of the box a little bit.  If we really don't want a big MD
file, then what's to stop us from doing something like

(define_generic_insn "add"
  (set (match_operand 0 "generic_operand")
       (plus (match_operand 1 "generic_operand)
             (match_operand 2 "generic_operand))))
{
  /* Lowering code */
}


Or you could even use a match operator.

Then you have one pattern for all additions, rather than one per mode.

jeff