[Bug middle-end/106833] Handle OPAQUE_TYPE in gimple_canonical_types_compatible_p

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106833

--- Comment #5 from Kewen Lin <linkw at gcc dot gnu.org> ---
> > I'm quoting tree.def, emphasis mine:
> > 
> > /* This is for types that will use MODE_OPAQUE in the back end.  They are
> > meant
> >    to be able to go in a register of some sort but are _EXPLICITLY NOT TO BE
> >    CONVERTED_ or operated on like INTEGER_TYPE.  They will have size and
> >    alignment information only.  */
> > DEFTREECODE (OPAQUE_TYPE, "opaque_type", tcc_type, 0)
> 
> Also the above says "have size and alignment information only" but the
> path you patch will look at TYPE_PRECISION and signedness.  Why, if that
> was necessary, did the TYPE_MODE check not trigger?
> 

After reading the documentation you posted, I think the patching place is
wrong. The previous TYPE_MODE check passed, as both TYPE_MODEs are E_XOmode.