New modref/ipa_modref optimization passes

Jan Hubicka hubicka@ucw.cz
Mon Sep 21 08:04:47 GMT 2020


> > 
> > The problem is:
> > 
> > alsize (struct array15_unknown & restrict a)
> > {
> > ...
> >   _2 = *a_13(D).dtype.rank;
> >   _3 = (integer(kind=8)) _2;
> > ...
> > }
> > }
> > and in main:
> > 
> >   struct array02_integer(kind=4) am;
> >   <bb 6> :
> >   MEM <c_char[8]> [(struct dtype_type *)&am + 24B] = {};
> >   am.dtype.elem_len = 4;
> >   am.dtype.rank = 2;
> >   am.dtype.type = 1;
> > ...
> >   _52 = alsize (&am);
> > 
> > Here array15_unknown and array02_integer are different structures with
> > different canonical types and thus we end up disambiguating the accesses
> > via base alias sets.
> > 
> > My understanding is that this _unknown array descriptor is supposed to
> > be universal and work with all kinds of arrays.
> 
> But the FE builds a new descriptor for each individual call and thus
> should build a universal descriptor for a call to an universal
> descriptor argument.

I see, so you would expect call to alsize to initialize things in
array15_unkonwn type?  That would work too.

Honza


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