Re: [tree-ssa] COND_EXPR lowering.

[law at redhat dot com]

In message <1067015177.14175.3041.camel@p4>, Andrew MacLeod writes:
 >On Fri, 2003-10-24 at 13:03, Diego Novillo wrote:
 >> On Fri, 2003-10-24 at 12:57, Andrew MacLeod wrote:
 >> 
 >> > We dont always use stmt replacement do we?
 >> > 
 >> > the insert_on_edge routines update the COND and THEN parts directly, so
 >> > it has to be changed there. Perhaps it would be limited to those 2
 >> > places, Im not sure. 
 >> > 
 >> The important thing is: will the statement iterators stop only at
 >> COND_EXPR?  Or will they also stop at THEN_CLAUSE and ELSE_CLAUSE?  If
 >> the latter is true, then both THEN_CLAUSE and ELSE_CLAUSE need to have
 >> their BB set and we need to keep that in sync with the COND_EXPR.
 >> 
 >> Perhaps we ought to change the semantics of COND_EXPR completely and not
 >> consider its clauses separate statements.  If we are going to do this,
 >> we need to make sure that the iterators never stop at the clauses, only
 >> at the parent COND_EXPR.
 >> 
 >Thats what Zdenek saying... they aren't stmts.  
And I think that is the core problem.  I think the arms ought to be
first class statements.

 >And iterators never did look at the clauses... I guess someone iterating
 >over everything may have decended into the clauses as part of their
 >processing, but thats all part of the patch. Besides, no one does it now
 >anyway. Its only an issue when we have the CFG, and then we use block
 >iterators
Yes, we had to explicitly recurse down into the arms.  That won't be
necessary anymore since the arms are allowed to have one and only 
one form -- a goto.

jeff