[gcc r13-3852] Fix up foperator_abs::op1_range [PR107569]

[gcc r13-3852] Fix up foperator_abs::op1_range [PR107569]

[Jakub Jelinek]

https://gcc.gnu.org/g:d943927ff860cea44a9cf64fc6d591a4a6e37f6f

commit r13-3852-gd943927ff860cea44a9cf64fc6d591a4a6e37f6f
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Nov 9 13:07:32 2022 +0100

    Fix up foperator_abs::op1_range [PR107569]
    
    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).
    
    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.

Diff:
---
 gcc/range-op-float.cc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc
index 44db81c1c1e..cc806438a19 100644
--- a/gcc/range-op-float.cc
+++ b/gcc/range-op-float.cc
@@ -1394,9 +1394,10 @@ foperator_abs::op1_range (frange &r, tree type,
     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;
 }