[PATCH] Fix bool vs. unsigned:1 vectorization (PR tree-optimization/79284)

[Jeff Law]

On 02/01/2017 01:21 AM, Richard Biener wrote:
>
> +/* Nonzero if TYPE represents a (scalar) boolean type or type
> +   in the middle-end compatible with it.  */
> +
> +#define INTEGRAL_BOOLEAN_TYPE_P(TYPE) \
> +  (TREE_CODE (TYPE) == BOOLEAN_TYPE            \
> +   || ((TREE_CODE (TYPE) == INTEGER_TYPE       \
> +       || TREE_CODE (TYPE) == ENUMERAL_TYPE)   \
> +       && TYPE_PRECISION (TYPE) == 1           \
> +       && TYPE_UNSIGNED (TYPE)))
>
> (just to quote what you proposed).
And my suggestion is to move the PRECISION/UNSIGNED checks so that 
they're tested for BOOLEAN_TYPEs as well.


>
> As of useless_type_conversion_p, I don't remember why we have
>
>       /* Preserve conversions to/from BOOLEAN_TYPE if types are not
>          of precision one.  */
>       if (((TREE_CODE (inner_type) == BOOLEAN_TYPE)
>            != (TREE_CODE (outer_type) == BOOLEAN_TYPE))
>           && TYPE_PRECISION (outer_type) != 1)
>         return false;
>
> it came with r173854 where you see other BOOLEAN_TYPE
> -> integral-type with precision 1 check changes, so a new predicate
> is very welcome IMHO.
Funny, it's your change ;-)  Looks like Kai added a gimple checker that 
verified that the operand of a TRUTH_NOT_EXPR must be compatible with 
boolean_type_node.

That check tripped (bz48989) on some Fortran code.  Your fix seems to 
imply that the Fortran front-end created non-1-precision BOOLEAN_TYPE 
object.


>
> all BOOLEAN_TYPEs but Adas have precision one and are unsigned
> (their TYPE_SIZE may vary though).  Adas larger precision boolean
> has only two valid values but needs to be able to encode some 'NaT'
> state.
>
> I think BOOLEAN_COMPATIBLE_TYPE_P would be misleading as it isn't
> equal to types_compatible_p (boolean_type_node, t).
>
> Maybe we want TWO_VALUED_UNSIGNED_INTEGRAL_TYPE_P ()? (ick)
> I thought "BOOLEAN" covers TWO_VALUED_UNSIGNED well enough but
> simply BOOLEAN_TYPE_P is easily confused with TREE_CODE () ==
> BOOLEAN_TYPE.
>
> I'm fine with changing the predicate to be more explicit, like
>
> #define INTEGRAL_BOOLEAN_TYPE_P(TYPE) \
>   (INTEGRAL_TYPE_P (TYPE) && TYPE_PRECISION (TYPE) == 1)
>
> not sure if we really need the TYPE_UNSIGNED check?  The middle-end
> has various places that just check for a 1-precision type when
> asking for a boolean context.
>
> So naming set aside, would you agree with the above definition?
> (modulo a && TYPE_UNSIGNED (TYPE))?
I could agree to that.  Alternately, we could restore the TYPE_PRECISION 
checks that Jakub removed in the vectorizer.

Jeff