[tree-ssa] tree-ssa vs. fold

[Jeff Sturm]

Going back to some older email...

On Sat, 7 Jun 2003, Richard Henderson wrote:
> On Fri, Jun 06, 2003 at 06:18:17PM -0400, Jeff Sturm wrote:
> > d) Fix fold() not to save_expr.
> >
> > Is d) the only real choice?  Am I missing something easy?
>
> While (d) is certainly desirable, there is an even more
> short-term solution that would probably benefit mainline
> as well: a SAVE_EXPR shouldn't have been created for a
> simple non-volatile DECL.

That sounds nice, though in this specific example it seems a little bit
perverse to teach save_expr about SSA_NAME nodes.  At this stage the
DECLs have already been rewritten for SSA.

It also may not solve the whole problem if there are other ways fold() can
return a non-GIMPLE tree other than SAVE_EXPR.

I can't think of anything short of factoring out the bits of fold()
suitable for GIMPLE.  Seems as though this routine is trying to be too
many things at once.

Jeff