On Fri, 17 Dec 2021 at 16:37, Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org> writes:
> > Hi,
> > The attached patch rearranges order of type-check for vec_perm_expr
> > and relaxes type checking for
> > lhs = vec_perm_expr<rhs1, rhs2, mask>
> >
> > when:
> > rhs1 == rhs2,
> > lhs is variable length vector,
> > rhs1 is fixed length vector,
> > TREE_TYPE (lhs) == TREE_TYPE (rhs1)
> >
> > I am not sure tho if this check is correct ? My intent was to capture
> > case when vec_perm_expr is used to "extend" fixed length vector to
> > it's VLA equivalent.
>
> VLAness isn't really the issue.  We want the same thing to work for
> -msve-vector-bits=256, -msve-vector-bits=512, etc., even though the
> vectors are fixed-length in that case.
>
> The principle is that for:
>
>   A = VEC_PERM_EXPR <B, C, D>;
>
> the requirements are:
>
> - A, B, C and D must be vectors
> - A, B and C must have the same element type
> - D must have an integer element type
> - A and D must have the same number of elements (NA)
> - B and C must have the same number of elements (NB)
>
> The semantics are that we create a joined vector BC (all elements of B
> followed by all element of C) and that:
>
>   A[i] = BC[D[i] % (NB+NB)]
>
> for 0 ≤ i < NA.
>
> This operation makes sense even if NA != NB.
Thanks for the suggestions, I tried to modify the patch accordingly.
Does it look OK ?
Passes bootstrap+test on aarch64-linux-gnu.

Thanks,
Prathamesh

>
> Thanks,
> Richard
>
> >
> > Thanks,
> > Prathamesh
> >
> > diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
> > index 672e384ef09..9f91878c468 100644
> > --- a/gcc/tree-cfg.c
> > +++ b/gcc/tree-cfg.c
> > @@ -4325,10 +4325,11 @@ verify_gimple_assign_ternary (gassign *stmt)
> >        break;
> >
> >      case VEC_PERM_EXPR:
> > -      if (!useless_type_conversion_p (lhs_type, rhs1_type)
> > -       || !useless_type_conversion_p (lhs_type, rhs2_type))
> > +      if (TREE_CODE (rhs1_type) != VECTOR_TYPE
> > +       || TREE_CODE (rhs2_type) != VECTOR_TYPE
> > +       || TREE_CODE (rhs3_type) != VECTOR_TYPE)
> >       {
> > -       error ("type mismatch in %qs", code_name);
> > +       error ("vector types expected in %qs", code_name);
> >         debug_generic_expr (lhs_type);
> >         debug_generic_expr (rhs1_type);
> >         debug_generic_expr (rhs2_type);
> > @@ -4336,11 +4337,14 @@ verify_gimple_assign_ternary (gassign *stmt)
> >         return true;
> >       }
> >
> > -      if (TREE_CODE (rhs1_type) != VECTOR_TYPE
> > -       || TREE_CODE (rhs2_type) != VECTOR_TYPE
> > -       || TREE_CODE (rhs3_type) != VECTOR_TYPE)
> > +      if (TREE_CODE (TREE_TYPE (rhs3_type)) != INTEGER_TYPE
> > +       || (TREE_CODE (rhs3) != VECTOR_CST
> > +           && (GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE
> > +                                 (TREE_TYPE (rhs3_type)))
> > +               != GET_MODE_BITSIZE (SCALAR_TYPE_MODE
> > +                                    (TREE_TYPE (rhs1_type))))))
> >       {
> > -       error ("vector types expected in %qs", code_name);
> > +       error ("invalid mask type in %qs", code_name);
> >         debug_generic_expr (lhs_type);
> >         debug_generic_expr (rhs1_type);
> >         debug_generic_expr (rhs2_type);
> > @@ -4348,15 +4352,18 @@ verify_gimple_assign_ternary (gassign *stmt)
> >         return true;
> >       }
> >
> > -      if (maybe_ne (TYPE_VECTOR_SUBPARTS (rhs1_type),
> > -                 TYPE_VECTOR_SUBPARTS (rhs2_type))
> > -       || maybe_ne (TYPE_VECTOR_SUBPARTS (rhs2_type),
> > -                    TYPE_VECTOR_SUBPARTS (rhs3_type))
> > -       || maybe_ne (TYPE_VECTOR_SUBPARTS (rhs3_type),
> > -                    TYPE_VECTOR_SUBPARTS (lhs_type)))
> > +      /* Accept lhs = vec_perm_expr<v, v, mask> if lhs is vector length agnostic,
> > +      and has same element type as v.  */
> > +      if (!TYPE_VECTOR_SUBPARTS (lhs_type).is_constant ()
> > +       && operand_equal_p (rhs1, rhs2, 0)
> > +       && TYPE_VECTOR_SUBPARTS (rhs1_type).is_constant ()
> > +       && TREE_TYPE (lhs_type) == TREE_TYPE (rhs1_type))
> > +     return false;
> > +
> > +      if (!useless_type_conversion_p (lhs_type, rhs1_type)
> > +       || !useless_type_conversion_p (lhs_type, rhs2_type))
> >       {
> > -       error ("vectors with different element number found in %qs",
> > -              code_name);
> > +       error ("type mismatch in %qs", code_name);
> >         debug_generic_expr (lhs_type);
> >         debug_generic_expr (rhs1_type);
> >         debug_generic_expr (rhs2_type);
> > @@ -4364,21 +4371,21 @@ verify_gimple_assign_ternary (gassign *stmt)
> >         return true;
> >       }
> >
> > -      if (TREE_CODE (TREE_TYPE (rhs3_type)) != INTEGER_TYPE
> > -       || (TREE_CODE (rhs3) != VECTOR_CST
> > -           && (GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE
> > -                                 (TREE_TYPE (rhs3_type)))
> > -               != GET_MODE_BITSIZE (SCALAR_TYPE_MODE
> > -                                    (TREE_TYPE (rhs1_type))))))
> > +      if (maybe_ne (TYPE_VECTOR_SUBPARTS (rhs1_type),
> > +                 TYPE_VECTOR_SUBPARTS (rhs2_type))
> > +       || maybe_ne (TYPE_VECTOR_SUBPARTS (rhs2_type),
> > +                    TYPE_VECTOR_SUBPARTS (rhs3_type))
> > +       || maybe_ne (TYPE_VECTOR_SUBPARTS (rhs3_type),
> > +                    TYPE_VECTOR_SUBPARTS (lhs_type)))
> >       {
> > -       error ("invalid mask type in %qs", code_name);
> > +       error ("vectors with different element number found in %qs",
> > +              code_name);
> >         debug_generic_expr (lhs_type);
> >         debug_generic_expr (rhs1_type);
> >         debug_generic_expr (rhs2_type);
> >         debug_generic_expr (rhs3_type);
> >         return true;
> >       }
> > -
> >        return false;
> >
> >      case SAD_EXPR: