diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index a66948ff1ace..88cbe1b14c79 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,8 @@
+2018-05-17  Jason Merrill  <jason@redhat.com>
+
+	* line-map.c (linemap_init): Use placement new.
+	* system.h: #include <new>.
+
 2018-03-14  David Malcolm  <dmalcolm@redhat.com>
 
 	* include/line-map.h (compare): New function on linenum_type.
diff --git a/libcpp/line-map.c b/libcpp/line-map.c
index a84084c99f05..b2ebfeb16d44 100644
--- a/libcpp/line-map.c
+++ b/libcpp/line-map.c
@@ -348,7 +348,7 @@ linemap_init (struct line_maps *set,
   /* PR33916, needed to fix PR82939.  */
   memset (set, 0, sizeof (struct line_maps));
 #else
-  *set = line_maps ();
+  new (set) line_maps();
 #endif
   set->highest_location = RESERVED_LOCATION_COUNT - 1;
   set->highest_line = RESERVED_LOCATION_COUNT - 1;
diff --git a/libcpp/system.h b/libcpp/system.h
index 719435df949a..76420e16cfbb 100644
--- a/libcpp/system.h
+++ b/libcpp/system.h
@@ -438,6 +438,10 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
 /* Some compilers do not allow the use of unsigned char in bitfields.  */
 #define BOOL_BITFIELD unsigned int
 
+#ifdef __cplusplus
+#include <new>
+#endif
+
 /* Poison identifiers we do not want to use.  */
 #if (GCC_VERSION >= 3000)
 #undef calloc