re PR c++/83897 (Useless __builtin_unreachable () emitted by the C++ FE)

	PR c++/83897
	* cp-gimplify.c (cp_maybe_instrument_return): Handle
	CLEANUP_POINT_EXPR.

	* g++.dg/cpp0x/pr83897.C: New test.

From-SVN: r256819

gcc/cp/ChangeLog

+2018-01-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/83897
+	* cp-gimplify.c (cp_maybe_instrument_return): Handle
+	CLEANUP_POINT_EXPR.
+
 2018-01-17  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/81054

gcc/cp/cp-gimplify.c

@@ -1581,6 +1581,7 @@ cp_maybe_instrument_return (tree fndecl)
 	  t = BIND_EXPR_BODY (t);
 	  continue;
 	case TRY_FINALLY_EXPR:
+	case CLEANUP_POINT_EXPR:
 	  t = TREE_OPERAND (t, 0);
 	  continue;
 	case STATEMENT_LIST:

gcc/testsuite/ChangeLog

+2018-01-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/83897
+	* g++.dg/cpp0x/pr83897.C: New test.
+
 2018-01-17  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR ipa/83051

gcc/testsuite/g++.dg/cpp0x/pr83897.C

+// PR c++/83897
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2 -fdump-tree-gimple" }
+// { dg-final { scan-tree-dump-not "__builtin_unreachable" "gimple" } }
+
+struct A {};
+struct B { int a; int b = 5; };
+
+A
+bar (B)
+{
+  return {};
+}