On Tue, May 18, 2021 at 11:41 AM Eric Botcazou <botca...@adacore.com> wrote: > > > 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; > > The '~' looks problematic if this is for Ada code, it ought to be: > > _19 = _18 ^ 1; > > See below.
So we do in fact require that all BOOLEAN_TYPEs are unsigned and that the two (valid) values it represents are 0 and 1? Because with a signed boolean and 0 / -1 the ^ 1 operation would be wrong. I suppose it should be ^ constant_boolean_node (type) which also works for singed bools. vector bools are signed after all ... > > 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. > > The patch is a nop, boolean types are always unsigned in Ada, see cstand.adb: > > Set_Is_Unsigned_Type (Standard_Boolean); > > but they have 8-bit precision instead of 1-bit precision so must be handled > with care, in particular BIT_NOT_EXPR should be avoided for them, see e.g. the > gimplifier: > > if (TYPE_PRECISION (TREE_TYPE (*expr_p)) == 1) > *expr_p = build1_loc (input_location, BIT_NOT_EXPR, > TREE_TYPE (*expr_p), > TREE_OPERAND (*expr_p, 0)); > else > *expr_p = build2_loc (input_location, BIT_XOR_EXPR, > TREE_TYPE (*expr_p), > TREE_OPERAND (*expr_p, 0), > build_int_cst (TREE_TYPE > (*expr_p), 1)); > > -- > Eric Botcazou > >
