Help in understanding ccp propagator
Revital1 Eres
ERES@il.ibm.com
Tue Jun 5 11:38:00 GMT 2007
> I can modify it to catch it pretty easily, just walk back a few vuses
> if the current set of vuses is defined by something that does not
> actually touch our offset.
This sounds like what I am trying to do in ccp...
> >
> > I am not sure I understand. The new patch uses the infrastructure of
> > the propagator and I do not see an indication in the dumps for vdefs
> > update after the lattice value is changed:
> >
> > 19930
> > 19931 Visiting statement:
> > 19932 D.61410.first = i0_62;
> > 19933
> > 19934 Lattice value changed to CONSTANT 0. Adding SSA edges to
worklist.
> > 19935
> >
> > Thanks again fo your help,
> > Revital
>
> So uh, how do you expect the propagator to notice when the used
> variables have changed if the things the vdefs produced by
> D.61410.first are not marked as change (so that the immediate uses of
> it get processed).
>
> You will need to add this if it is not there already.
>
>
> Normally, the propagator says "oh, the lattice value of D_64 changed,
> let me mark all it's immediate uses for reprocessing". The only thing
> that links memory defs to memory uses is the vdef/vuses, so you will
> have to be able to process and mark those
I thought the engine suppose to take care of that. I do not understand
why this case is different from other cases where we propagate for
vdefs...
Thanks again,
Revital
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