http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48098
Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED AssignedTo|unassigned at gcc dot |rguenth at gcc dot gnu.org |gnu.org | --- Comment #6 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-03-14 10:43:09 UTC --- (In reply to comment #5) > Just swapping the order of arguments to useless_type_conversion_p works too. > If we consider build_vector_from_val as conversion from sc's type to the inner > type of the vector, then vectype's inner type as outer_type needs to go first: > > --- gcc/tree.c.jj 2011-03-11 12:16:39.000000000 +0100 > +++ gcc/tree.c 2011-03-14 10:57:21.000000000 +0100 > @@ -1376,8 +1376,8 @@ build_vector_from_val (tree vectype, tre > if (sc == error_mark_node) > return sc; > > - gcc_assert (useless_type_conversion_p (TREE_TYPE (sc), > - TREE_TYPE (vectype))); > + gcc_assert (useless_type_conversion_p (TREE_TYPE (vectype), > + TREE_TYPE (sc))); > > v = VEC_alloc (constructor_elt, gc, nunits); > for (i = 0; i < nunits; ++i) The assert is supposed to make sure that in vectorized code vector extracts use the correct type for assignments to scalars. Thus if we have before vectorization scalar = X; and we vectorized the code that produced X we should use a vector type for the vector result X that has an element type that is trivially convertible to that of the above scalar. Thus, before and after vectorization useless_type_conversion_p (type-of-scalar, type-of-vector-element-type) should be true. The scalar X is sc above which is trivially convertible to scalar, so if type-of-vector-element-type is trivially convertible to X then it's trivially convertible to scalar. Thus the assert is correct. I think treating restrict as ordinary qualifier in make_vector_type is bogus, similarly not properly maintaining a ref-all "qualification". I suppose nobody thought of pointer vector element types before. I'll cook up a patch.