[PUSHED 6/8] Use irange API in test_for_singularity.
Tue Aug 4 09:55:55 GMT 2020
On 8/4/20 8:58 AM, Richard Biener wrote:
> On Tue, Aug 4, 2020 at 8:40 AM Aldy Hernandez via Gcc-patches
> <firstname.lastname@example.org> wrote:
>> * vr-values.c (test_for_singularity): Use irange API.
>> (simplify_using_ranges::simplify_cond_using_ranges_1): Do not
>> special case VR_RANGE.
>> gcc/vr-values.c | 13 ++++++++-----
>> 1 file changed, 8 insertions(+), 5 deletions(-)
>> diff --git a/gcc/vr-values.c b/gcc/vr-values.c
>> index 90ba8fca246..e78b25596b0 100644
>> --- a/gcc/vr-values.c
>> +++ b/gcc/vr-values.c
>> @@ -3480,10 +3480,13 @@ test_for_singularity (enum tree_code cond_code, tree op0,
>> value range information we have for op0. */
>> if (min && max)
>> - if (compare_values (vr->min (), min) == 1)
>> - min = vr->min ();
>> - if (compare_values (vr->max (), max) == -1)
>> - max = vr->max ();
>> + tree type = TREE_TYPE (op0);
>> + tree tmin = wide_int_to_tree (type, vr->lower_bound ());
>> + tree tmax = wide_int_to_tree (type, vr->upper_bound ());
> I guess with symbolic ranges this just doesn't work anymore
> (or rather will give a pessimistinc upper/lower bound)?
Yes, though we do slightly better than VARYING. The symbolic
normalizing code will rewrite [SYM, 5] as [-INF, 5], etc.
When I implemented this originally in the ranger branch, I
pessimistically downgraded all symbolics to [MIN,MAX] to see if there
was any difference in the generated code. There wasn't.
I think most of vr-values.c does no better without symbolics, with the
exception of compare_value* and the corresponding code that handles
comparisons and equivalences.
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