re PR c++/80119 (-Wmaybe-uninitialized wrongly flags the body of a short-circuited if-clause)

	PR c++/80119
	* cp-gimplify.c (cp_fold): Strip CLEANUP_POINT_EXPR if the expression
	doesn't have side effects.

	* g++.dg/warn/Wuninitialized-9.C: New test.

From-SVN: r246461

gcc/cp/ChangeLog

+2017-03-24  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/80119
+	* cp-gimplify.c (cp_fold): Strip CLEANUP_POINT_EXPR if the expression
+	doesn't have side effects.
+
 2017-03-23  Jason Merrill  <jason@redhat.com>
 
 	PR c++/80150 - ICE with overloaded variadic deduction.

gcc/cp/cp-gimplify.c

@@ -2056,6 +2056,14 @@ cp_fold (tree x)
   code = TREE_CODE (x);
   switch (code)
     {
+    case CLEANUP_POINT_EXPR:
+      /* Strip CLEANUP_POINT_EXPR if the expression doesn't have side
+	 effects.  */
+      r = cp_fold_rvalue (TREE_OPERAND (x, 0));
+      if (!TREE_SIDE_EFFECTS (r))
+	x = r;
+      break;
+
     case SIZEOF_EXPR:
       x = fold_sizeof_expr (x);
       break;

gcc/testsuite/ChangeLog

+2017-03-24  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/80119
+	* g++.dg/warn/Wuninitialized-9.C: New test.
+
 2017-03-24  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
 	* gcc.target/s390/target-attribute/tattr-3.c: Adjust error message

gcc/testsuite/g++.dg/warn/Wuninitialized-9.C

+// PR c++/80119
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wuninitialized" }
+
+#include <type_traits>
+
+template <bool b>
+void failing_function(std::integral_constant<bool, b>)
+{
+   int i;
+   if (b && (i = 4)) {
+      ++i; // { dg-bogus "may be used uninitialized" }
+   }
+}
+
+int main (void)
+{
+   failing_function(std::false_type());
+}