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Re: range_int_cst_p handling in extract_range_from_binary_expr_1
- From: Richard Sandiford <richard dot sandiford at linaro dot org>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 22 Sep 2017 18:01:03 +0100
- Subject: Re: range_int_cst_p handling in extract_range_from_binary_expr_1
- Authentication-results: sourceware.org; auth=none
- References: <87vakd1sn3.fsf@linaro.org> <CAFiYyc0JzxHKEA12wvh+ggWsAyne_JU7DFn=r9=0cK1WJEL1fA@mail.gmail.com>
Richard Biener <richard.guenther@gmail.com> writes:
> On Wed, Sep 20, 2017 at 2:06 PM, Richard Sandiford
> <richard.sandiford@linaro.org> wrote:
>> extract_range_from_binary_expr_1 had:
>>
>> if (range_int_cst_p (&vr0)
>> && range_int_cst_p (&vr1)
>> && TYPE_OVERFLOW_WRAPS (expr_type))
>> ...
>> ...
>> extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
>>
>> but extract_range_from_multiplicative_op_1 also requires range_int_cst_p.
>> I think we should bail out if either range isn't a constant.
>>
>> This might only be theoretical with current sources, but it's needed
>> once polynomial constants are added.
>>
>> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linus-gnu.
>> OK to install?
>
> extract_range_from_multiplicative_op_1 also allows anti-ranges but indeed
> requires INTEGER_CSTs. Note it won't get anti-ranges because we handle
> this case by ranges_from_anti_range.
>
> Thus ok if you also remove the apparent anti-range handling from
> extract_range_from_multiplicative_op_1 (in the assert).
Thanks, here's what I committed after testing as before.
Richard
2017-09-22 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>
gcc/
* tree-vrp.c (extract_range_from_multiplicative_op_1): Assert
for VR_RANGE only; don't allow VR_ANTI_RANGE.
(extract_range_from_binary_expr_1): Don't call
extract_range_from_multiplicative_op_1 if !range_int_cst_p.
Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c 2017-09-21 22:35:16.639777740 +0100
+++ gcc/tree-vrp.c 2017-09-22 17:46:45.207205032 +0100
@@ -1851,8 +1851,7 @@ extract_range_from_multiplicative_op_1 (
|| code == ROUND_DIV_EXPR
|| code == RSHIFT_EXPR
|| code == LSHIFT_EXPR);
- gcc_assert ((vr0->type == VR_RANGE
- || (code == MULT_EXPR && vr0->type == VR_ANTI_RANGE))
+ gcc_assert (vr0->type == VR_RANGE
&& vr0->type == vr1->type);
rtype = vr0->type;
@@ -2462,9 +2461,14 @@ extract_range_from_binary_expr_1 (value_
signop sign = TYPE_SIGN (expr_type);
unsigned int prec = TYPE_PRECISION (expr_type);
- if (range_int_cst_p (&vr0)
- && range_int_cst_p (&vr1)
- && TYPE_OVERFLOW_WRAPS (expr_type))
+ if (!range_int_cst_p (&vr0)
+ || !range_int_cst_p (&vr1))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ if (TYPE_OVERFLOW_WRAPS (expr_type))
{
typedef FIXED_WIDE_INT (WIDE_INT_MAX_PRECISION * 2) vrp_int;
typedef generic_wide_int