Re: Higher level RTL issues

[law at redhat dot com]

  In message <B7299F68-C733-11D5-9F25-0030657B5340@cgsoftware.com>you write:
  > > None that you wouldn't have to do anyway, since you need to update the 
  > > use's chain to point to the new def anyway.  The ID number is part of 
  > > the def/use structure, so doing the required update makes it work.
  > > Though i think this is what you meant, i'm just having a bit of trouble 
  > > parsing your sentence. Criminal law class does it to me.
  > > Remember, we have all the uses for a def, too, so when you remove the 
  > > def, you can just automatically update all the uses to the new def 
  > > pretty simply (since, in the case of dominator optimizations, we know 
  > > which def is the new one).
  > 
  > Scratch that, i forgot you are talking about dominator optimizations 
  > done *before* we build the links.
Precisely.

  > I was thinking of doing it as a value numbering pass once we *had* ssa 
  > form.
Understood.  And your scheme may make sense in that space, I haven't
worked through GVN in enough detail to have any feel one way or the
other.

jeff