[tcb] Incremental SSA updates

[Daniel Berlin]

On Fri, 2005-02-11 at 16:59 +0100, Zdenek Dvorak wrote:
> Hello,
> 
> > > > Just changing the phi_result to null lets me remove the unmark/mark
> > > > calls, without the rest of your patch apply.
> > > > I highly suspect the bug is elsewhere in your code if this test is
> > > > failing.
> > > > The perfect_nestify code doesn't do anything illegal on that testcase.
> > > 
> > > use the patch below to reproduce the problem.
> > > rewrite_into_loop_closed_ssa currently masks the problem,
> > > at the expense of causing a misscompilation.
> > 
> > Uh, of course that won't work.
> > It doesn't have valid ssa until rewrite_into_loop_closed_ssa is
> > finished.
> > We ask it to do renaming.
> 
> nope.  rewrite_into_loop_closed_ssa expects a valid ssa form on entry,
> and will not work correctly otherwise.  If you need updating ssa form,
> you must do it by other means (rewrite_ssa_into_ssa in mainline).

Okay, then we need a rewrite_into_ssa (false) call before it.
I'll apply your patch and test such a change.