diff mbox series

Fix up foperator_abs::op1_range [PR107569]

Message ID Y2uHDeXiivo401ni@tucnak
State New
Headers
Series Fix up foperator_abs::op1_range [PR107569] |

Commit Message

Jakub Jelinek Nov. 9, 2022, 10:55 a.m. UTC 
  Hi!

foperator_abs::op1_range works except for the NaN handling,
from:
[frange] double [-Inf, 1.79769313486231570814527423731704356798070567525844996599e+308 (0x0.fffffffffffff8p+1024)]
lhs it computes r
[frange] double [-1.79769313486231570814527423731704356798070567525844996599e+308 (-0x0.fffffffffffff8p+1024), 1.79769313486231570814527423731704356798070567525844996599e+308 (0x0.fffffffffffff8p+1024)] +-NAN
which is correct except for the +-NAN part.
For r before the final step it makes sure to add -NAN if there is +NAN
in the lhs range, but the final r.union_ makes it unconditional +-NAN,
because the frange ctor sets +-NAN.
So, I think we need to clear it (or have some set variant which
says not to set NAN).

This patch fixes that, but isn't enough to fix the PR, something in
the assumptions handling is still broken (and the PR has other parts).

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2022-11-09  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/107569
	* range-op-float.cc (foperator_abs::op1_range): Clear NaNs
	from the negatives frange before unioning it into r.


	Jakub

Comments

Aldy Hernandez Nov. 9, 2022, 11:32 a.m. UTC | #1 
On Wed, Nov 9, 2022 at 11:55 AM Jakub Jelinek <jakub@redhat.com> wrote:
>
> Hi!
>
> foperator_abs::op1_range works except for the NaN handling,
> from:
> [frange] double [-Inf, 1.79769313486231570814527423731704356798070567525844996599e+308 (0x0.fffffffffffff8p+1024)]
> lhs it computes r
> [frange] double [-1.79769313486231570814527423731704356798070567525844996599e+308 (-0x0.fffffffffffff8p+1024), 1.79769313486231570814527423731704356798070567525844996599e+308 (0x0.fffffffffffff8p+1024)] +-NAN
> which is correct except for the +-NAN part.
> For r before the final step it makes sure to add -NAN if there is +NAN
> in the lhs range, but the final r.union_ makes it unconditional +-NAN,
> because the frange ctor sets +-NAN.
> So, I think we need to clear it (or have some set variant which
> says not to set NAN).
>
> This patch fixes that, but isn't enough to fix the PR, something in
> the assumptions handling is still broken (and the PR has other parts).

LGTM.

Sorry I haven't gotten to the PR yet.  I'll poke at it later today.

Thanks.
Aldy

>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2022-11-09  Jakub Jelinek  <jakub@redhat.com>
>
>         PR tree-optimization/107569
>         * range-op-float.cc (foperator_abs::op1_range): Clear NaNs
>         from the negatives frange before unioning it into r.
>
> --- gcc/range-op-float.cc.jj    2022-11-06 11:56:27.138137781 +0100
> +++ gcc/range-op-float.cc       2022-11-08 18:13:18.026974667 +0100
> @@ -1280,9 +1280,10 @@ foperator_abs::op1_range (frange &r, tre
>      return true;
>    // Then add the negative of each pair:
>    // ABS(op1) = [5,20] would yield op1 => [-20,-5][5,20].
> -  r.union_ (frange (type,
> -                   real_value_negate (&positives.upper_bound ()),
> -                   real_value_negate (&positives.lower_bound ())));
> +  frange negatives (type, real_value_negate (&positives.upper_bound ()),
> +                   real_value_negate (&positives.lower_bound ()));
> +  negatives.clear_nan ();
> +  r.union_ (negatives);
>    return true;
>  }
>
>
>         Jakub
>
diff mbox series

Patch

--- gcc/range-op-float.cc.jj	2022-11-06 11:56:27.138137781 +0100
+++ gcc/range-op-float.cc	2022-11-08 18:13:18.026974667 +0100
@@ -1280,9 +1280,10 @@  foperator_abs::op1_range (frange &r, tre
     return true;
   // Then add the negative of each pair:
   // ABS(op1) = [5,20] would yield op1 => [-20,-5][5,20].
-  r.union_ (frange (type,
-		    real_value_negate (&positives.upper_bound ()),
-		    real_value_negate (&positives.lower_bound ())));
+  frange negatives (type, real_value_negate (&positives.upper_bound ()),
+		    real_value_negate (&positives.lower_bound ()));
+  negatives.clear_nan ();
+  r.union_ (negatives);
   return true;
 }