------- Comment #12 from rakdver at kam dot mff dot cuni dot cz 2010-01-16
13:24 -------
Subject: Re: [4.5 Regression] -O2 and verify_stmts
failed again
> > ------- Comment #10 from rakdver at gcc dot gnu dot org 2010-01-16 12:53
> > -------
> > /* Reject a tailcall if the type conversion might need
> > 285 additional code. */
> > 286 if (gimple_assign_cast_p (stmt)
> > 287 && TYPE_MODE (TREE_TYPE (dest)) != TYPE_MODE
> > (TREE_TYPE (src_var)))
> > 288 return false;
> >
> > This is suspicious; replacing the weird TYPE_MODE check with
> > useless_type_conversion_p fixes the problem.
>
> Correct, but for useless_type_conversion_p we can reject any conversions
> in the IL since only !useless_type_conversion_p remain.
right
> I suppose the code was explicitly trying to allow sign-changing
> (but not precision changing as it does), or conversion to/from
> pointers.
>
> Thus, if you want to go the useless_type_conversion_p route simply
> reject all conversions and only allow plain SSA name copies...
this might be overly restrictive; it should be quite easy to add the
appropriate casts, instead.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42749
