re PR c/79199 (ICE with -Wduplicated-branches)

	PR c/79199
	* fold-const.c (operand_equal_p) [COND_EXPR]: Use OP_SAME_WITH_NULL
	for the third operand.

	* c-c++-common/Wduplicated-branches-13.c: New test.

From-SVN: r244928

gcc/ChangeLog

+2017-01-26  Marek Polacek  <polacek@redhat.com>
+
+	PR c/79199
+	* fold-const.c (operand_equal_p) [COND_EXPR]: Use OP_SAME_WITH_NULL
+	for the third operand.
+
 2017-01-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/79236

gcc/fold-const.c

@@ -3147,7 +3147,7 @@ operand_equal_p (const_tree arg0, const_tree arg1, unsigned int flags)
 				      TREE_OPERAND (arg1, 0), flags));
 
 	case COND_EXPR:
-	  if (! OP_SAME (1) || ! OP_SAME (2))
+	  if (! OP_SAME (1) || ! OP_SAME_WITH_NULL (2))
 	    return 0;
 	  flags &= ~OEP_ADDRESS_OF;
 	  return OP_SAME (0);

gcc/testsuite/ChangeLog

+2017-01-26  Marek Polacek  <polacek@redhat.com>
+
+	PR c/79199
+	* c-c++-common/Wduplicated-branches-13.c: New test.
+
 2017-01-26  David Sherwood  <david.sherwood@arm.com>
 
 	PR middle-end/79212

gcc/testsuite/c-c++-common/Wduplicated-branches-13.c

+/* PR c/79199 */
+/* { dg-do compile } */
+/* { dg-options "-Wduplicated-branches" } */
+
+unsigned int a, b, c, d, e;
+void
+fn1 (void)
+{
+  if (0) /* { dg-warning "this condition has identical branches" } */
+    {
+      if (d > 4294967293)
+	(void) 5;
+      c = d;
+      b = e | a;
+    }
+  else
+    {
+      if (d > 4294967293)
+	(void) 5;
+      c = d;
+      b = e | a;
+    }
+}