From: Aldy Hernandez <aldyh@redhat.com>
Date: Thu, 8 Oct 2020 09:33:30 +0000 (+0200)
Subject: Fix PR97315 (part 2 of 2)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=91ae6930ed4a87d7b8e25e10378388b3f0dc1729;p=gcc.git

Fix PR97315 (part 2 of 2)

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);
+}