DImode speedup on i386

[Jeffrey A Law]

  In message <Pine.SOL.3.90.980220113102.20928F-100000@clouseau.informatik.rwthhen.de>you write:
  > > One general note -- you have to be *extremely* careful defining DImode
  > > patterns on the x86 due to the bad interactions with register
  > > reloading.
  > 
  > When the patch was written, I simply used the constraints from
  > the addi3/subdi3 patterns to avoid problems.
  > Since it's about a year old (I've tried a couple of times to get it into
  > gcc2, without success), it's quite possible that things have changed. I'll
  > check that and implement Richard Henderson's suggestion, and send an updated
  > patch.
OK.  Yea, if you use the same constraints as the existing adddi3
and related patterns you *should* be OK.

Looking forward to the updated patch! :-)

jeff