[PUSHED] Fix PR97315 (part 2 of 2)

[Aldy Hernandez via Gcc-patches]

This fixes the second testcase in the PR.

I've tested Andrew's patch and pushed it.
Aldy

    gcc/ChangeLog:

            PR tree-optimization/97315
            * range-op.cc (value_range_with_overflow): Change any
            non-overflow calculation in which both bounds are
            overflow/underflow to be undefined.

    gcc/testsuite/ChangeLog:

            * gcc.dg/pr97315-2.c: New test.

diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 87c6d82f2ac..22bc23c1bbf 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -287,6 +287,15 @@ value_range_with_overflow (irange &r, tree type,
     }
   else
     {
+      // If both bounds either underflowed or overflowed, then the result
+      // is undefined.
+      if ((min_ovf == wi::OVF_OVERFLOW && max_ovf == wi::OVF_OVERFLOW)
+         || (min_ovf == wi::OVF_UNDERFLOW && max_ovf == wi::OVF_UNDERFLOW))
+       {
+         r.set_undefined ();
+         return;
+       }
+
       // If overflow does not wrap, saturate to [MIN, MAX].
       wide_int new_lb, new_ub;
       if (min_ovf == wi::OVF_UNDERFLOW)
diff --git a/gcc/testsuite/gcc.dg/pr97315-2.c 
b/gcc/testsuite/gcc.dg/pr97315-2.c
new file mode 100644
index 00000000000..5dd1b6a3fc7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr97315-2.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void c(int);
+
+int a;
+void b()
+{
+  if (a >= 2147483647)
+    c(a + 1);
+}