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Re: Tree-SSA self checking infrastructure


On Wed, 2003-11-19 at 13:38, Jan Hubicka wrote:
> > On Wed, 2003-11-19 at 13:04, law@redhat.com wrote:
> > 
> > > 
> > >  >3) SSA form testing
> > >  >   We should have verify_ssa that ensures that stream is in valid SSA
> > >  >   form.  I am not quite sure how to best implement this, but I guess I
> > >  >   can simply verify that all the pointers points corectly and that each
> > >  >   use is dominated by the def it points to.  Correct?
> > > Right.  Each use needs to be dominated by its def and there should only be
> > > a single def for each SSA_NAME.
> > > 
> > 
> > Isnt that already verified in SSA->normal?
> It would be easier to have this in simple function so one can call it in
> the middle of queue.

I beleive we put it there because the information naturally flowed out
of the work SSA->normal was doing when trying to coalesce ssa versions
together. An SSA version which the live range analysis determines is
live on entry to the program which also has a DEF in the program
somewhere is determined to be in error, and we abort. 

You could call it from anywhere, but its in the live-on-entry
calculator, so you'd be doing some additional work. You could call
create_ssa_var_map() to create the partition set, followed by
live_on_entry() then throw away the results...

Wouldnt be too difficult... just a waste of some compile time.

Andrew


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