Re: [tree-ssa] empty_stmt_nodes, deleted statements, iterators, and gsi_step_bb

[Daniel Berlin <dberlin at dberlin dot org>]

On Friday, November 29, 2002, at 01:17  PM, Diego Novillo wrote:

> On Fri, 29 Nov 2002, Daniel Berlin wrote:
>
> > On Friday, November 29, 2002, at 12:50  PM, Diego Novillo wrote:
> >
> > > On Fri, 29 Nov 2002, Andrew Macleod wrote:
> > >
> > > > So why does the builder do this? why doesn't it do something such as
> > > > link a compound statement into the tree, hang an empty_stmt node off
> > > > it,
> > > > and then point to that?
> > > Because the CFG builder is not particularly bright.  Your
> > > suggestion sounds good to me.  Care to implement it?  :)
> > You have to hang two, no?
> > :)
> Hmm, maybe, but I wouldn't have thought it to be necessary.  I
> really haven't given much thought to it yet.  In principle,
> inserting a statement is a matter of
>
> 1- Create a COMPOUND_EXPR containing the new statement (N) and
>    the old statement (O).  The relative order between N and O
>    depends on whether you want to insert before or after.
> 2- Replace O with the new COMPOUND_EXPR.
This is what i do to insert in SSAPRE.

> You can then call one of the gimplifier functions to re-chain the
> function (rationalize_compound_expr) so that the chain is
> made right associative.
Never realized I should do this part though.
Next thing i was gonna tackle (after cleanup and bootstrap work) was 
trying to rewrap with WFL's in a reasonable way.

> Diego.