Signedness of boolean types (and Ada)

[Andrew Pinski via Gcc]

I noticed while debugging why my "A?CST1:CST0" patch was broken for
Ada, I noticed the following ranges for boolean types:
  # RANGE [0, 1] NONZERO 1
  _14 = checks__saved_checks_tos.482_2 > 0;
  # RANGE [0, 255] NONZERO 1
  _18 = _14 == 0;
  _19 = ~_18;
  # RANGE [0, 1] NONZERO 1
  _15 = _19;
  if (_15 != 0)
    goto <bb 7>; [50.00%]
  else
    goto <bb 6>; [50.00%]

Seems like there is a misunderstanding of TYPE_UNSIGNED for boolean
types and that is what is causing the problem in the end. As the above
gets optimized to be always true. My patch just happens to cause the
~_18 to be produced which is later on miscompiled.

Should TYPE_UNSIGNED be always set for boolean types?

I am testing the below patch to see if it fixes the problem, if we
should assume TYPE_UNSIGNED is true for boolean types.  If we should
not assume that, then there is a problem with conversion between
boolean types that have TYPE_UNSIGNED mismatched.

Thanks,
Andrew Pinski

diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
index 232b552a60c..4e839f3b8ab 100644
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -1687,7 +1687,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
gnu_expr, bool definition)

          gnu_type = make_node (is_boolean ? BOOLEAN_TYPE : ENUMERAL_TYPE);
          TYPE_PRECISION (gnu_type) = esize;
-         TYPE_UNSIGNED (gnu_type) = is_unsigned;
+         TYPE_UNSIGNED (gnu_type) = is_boolean ? true : is_unsigned;
          set_min_and_max_values_for_integral_type (gnu_type, esize,
                                                    TYPE_SIGN (gnu_type));
          process_attributes (&gnu_type, &attr_list, true, gnat_entity);