Re: tuples: initial infrastructure

[Aldy Hernandez <aldyh at redhat dot com>]

> > +/* A sequences of gimple statements.  */
> > +#define GS_SEQP_FIRST(S)	(S)->first
> > +#define GS_SEQP_LAST(S)		(S)->last
> > +#define GS_SEQ_FIRST(S)		(S).first
> > +#define GS_SEQ_LAST(S)		(S).last
> 
> Why do you have both of these?

Most places in the gimplifier we will send sequences as pointers, but
for saving state (see gimplify_and_add), we use local variables.  I figured
it'd be better than doing GS_SEQP_FIRST(&non_pointer), but I can if you
prefer.

> Otherwise it looks ok.  I figure you'll want to build a set of
> iterators and such for gs_sequences, like for tree-iterator.[ch].

Yee haw!  Thanks so much for reviewing this.

I'll commit to the branch and start the long haul.

Aldy