On Wed, Oct 28, 2015 at 2:13 PM, Ilya Enkovich <enkovich....@gmail.com> wrote:
> Hi,
>
> Testing boolean vector conversions I found several runtime regressions
> and investigation showed it's due to incorrect conversion caused by
> unsigned boolean type. When boolean vector is represented as an
> integer vector on target it's a signed integer actually. Unsigned
> boolean type was chosen due to possible single bit values, but for
> multiple bit values it causes wrong casting. The easiest way to fix
> it is to use signed boolean value. The following patch does this and
> fixes my problems with conversion. Bootstrapped and tested on
> x86_64-unknown-linux-gnu. Is it OK?
Hmm. Actually formally the "boolean" vectors were always 0 or -1
(all bits set). That is also true for a signed boolean with precision 1
but with higher precision what makes sure to sign-extend 'true'?
So it's far from an obvious change, esp as you don't change the
precision == 1 case. [I still think we should have precision == 1
for all boolean types]
Richard.
> Thanks,
> Ilya
> --
> gcc/
>
> 2015-10-28 Ilya Enkovich <enkovich....@gmail.com>
>
> * optabs.c (expand_vec_cond_expr): Always get sign from type.
> * tree.c (wide_int_to_tree): Support negative values for boolean.
> (build_nonstandard_boolean_type): Use signed type for booleans
> with precision greater than 1.
>
>
> diff --git a/gcc/optabs.c b/gcc/optabs.c
> index e1ac0b8..37a67f1 100644
> --- a/gcc/optabs.c
> +++ b/gcc/optabs.c
> @@ -5373,7 +5373,6 @@ expand_vec_cond_expr (tree vec_cond_type, tree op0,
> tree op1, tree op2,
> op0a = TREE_OPERAND (op0, 0);
> op0b = TREE_OPERAND (op0, 1);
> tcode = TREE_CODE (op0);
> - unsignedp = TYPE_UNSIGNED (TREE_TYPE (op0a));
> }
> else
> {
> @@ -5382,9 +5381,9 @@ expand_vec_cond_expr (tree vec_cond_type, tree op0,
> tree op1, tree op2,
> op0a = op0;
> op0b = build_zero_cst (TREE_TYPE (op0));
> tcode = LT_EXPR;
> - unsignedp = false;
> }
> cmp_op_mode = TYPE_MODE (TREE_TYPE (op0a));
> + unsignedp = TYPE_UNSIGNED (TREE_TYPE (op0a));
>
>
> gcc_assert (GET_MODE_SIZE (mode) == GET_MODE_SIZE (cmp_op_mode)
> diff --git a/gcc/tree.c b/gcc/tree.c
> index e77d4b8..712390f 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -1451,7 +1451,7 @@ wide_int_to_tree (tree type, const wide_int_ref &pcst)
> case BOOLEAN_TYPE:
> /* Cache false or true. */
> limit = 2;
> - if (hwi < 2)
> + if (IN_RANGE (hwi, 0, 1))
> ix = hwi;
> break;
>
> @@ -8076,7 +8076,10 @@ build_nonstandard_boolean_type (unsigned HOST_WIDE_INT
> precision)
>
> type = make_node (BOOLEAN_TYPE);
> TYPE_PRECISION (type) = precision;
> - fixup_unsigned_type (type);
> + if (precision > 1)
> + fixup_signed_type (type);
> + else
> + fixup_unsigned_type (type);
>
> if (precision <= MAX_INT_CACHED_PREC)
> nonstandard_boolean_type_cache[precision] = type;
