On 03 Nov 14:42, Richard Biener wrote:
> On Wed, Oct 28, 2015 at 4:30 PM, Ilya Enkovich <enkovich....@gmail.com> wrote:
> > 2015-10-28 18:21 GMT+03:00 Richard Biener <richard.guent...@gmail.com>:
> >> 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.
> >>
> >
> > For 1 bit precision signed type value 1 is out of range, right? This might
> > break
> > in many place due to used 1 as true value.
>
> For vectors -1 is true. Did you try whether it breaks many places?
> build_int_cst (type, 1) should still work fine.
>
> Richard.
>
I tried it and didn't find any new failures. So looks I was wrong assuming it
should cause many failures. Testing is not complete because many SPEC
benchmarks are failing to compile on -O3 for AVX-512 on trunk. But I think we
may proceed with signed type and fix constant generation issues if any
revealed. This patch was bootstrapped and regtested on
x86_64-unknown-linux-gnu. OK for trunk?
Thanks,
Ilya
--
gcc/
2015-11-09 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.
diff --git a/gcc/optabs.c b/gcc/optabs.c
index fdcdc6a..44971ad 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -5365,7 +5365,6 @@ 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
{
@@ -5374,9 +5373,9 @@ 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 18d6544..6fb4c09 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -1437,7 +1437,7 @@ 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;
@@ -8069,7 +8069,7 @@ build_nonstandard_boolean_type (unsigned HOST_WIDE_INT
precision)
type = make_node (BOOLEAN_TYPE);
TYPE_PRECISION (type) = precision;
- fixup_unsigned_type (type);
+ fixup_signed_type (type);
if (precision <= MAX_INT_CACHED_PREC)
nonstandard_boolean_type_cache[precision] = type;
