[gcc r13-3456] [PR tree-optimization/107355] Handle NANs in abs range-op entry.

[Aldy Hernandez <aldyh@gcc.gnu.org>]

https://gcc.gnu.org/g:5bcd92d0d4029f3d1d2eacc0e2bff1685545b74f

commit r13-3456-g5bcd92d0d4029f3d1d2eacc0e2bff1685545b74f
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Mon Oct 24 12:37:25 2022 +0200

    [PR tree-optimization/107355] Handle NANs in abs range-op entry.
    
    The problem here is that the threader is coming up with a path where
    the only valid result is a NAN.  When the abs op1_range entry is
    trying to add the negative posibility, it attempts to get the bounds
    of the working range.  NANs don't have bounds so they need to be
    special cased.
    
            PR tree-optimization/107355
    
    gcc/ChangeLog:
    
            * range-op-float.cc (foperator_abs::op1_range): Handle NAN.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.dg/tree-ssa/pr107355.c: New test.

Diff:
---
 gcc/range-op-float.cc                    |  9 +++++++++
 gcc/testsuite/gcc.dg/tree-ssa/pr107355.c | 13 +++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc
index 8777bc70d71..04208c88dd1 100644
--- a/gcc/range-op-float.cc
+++ b/gcc/range-op-float.cc
@@ -1269,6 +1269,15 @@ foperator_abs::op1_range (frange &r, tree type,
   positives.update_nan (/*sign=*/false);
   positives.intersect (lhs);
   r = positives;
+  // Add -NAN if relevant.
+  if (r.maybe_isnan ())
+    {
+      frange neg_nan;
+      neg_nan.set_nan (type, true);
+      r.union_ (neg_nan);
+    }
+  if (r.known_isnan ())
+    return true;
   // Then add the negative of each pair:
   // ABS(op1) = [5,20] would yield op1 => [-20,-5][5,20].
   r.union_ (frange (type,
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr107355.c b/gcc/testsuite/gcc.dg/tree-ssa/pr107355.c
new file mode 100644
index 00000000000..40796344bfb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr107355.c
@@ -0,0 +1,13 @@
+// { dg-do compile }
+// { dg-options "-O2 -fno-guess-branch-probability -fsanitize=float-cast-overflow --param=max-jump-thread-duplication-stmts=240" }
+
+float f;
+
+void
+foo (double d)
+{
+  (char) f;
+  long l = __builtin_fabs (d);
+  (char) f;
+  (long) d;
+}