Add a tetst for PR middle-end/83471

	PR middle-end/83471
	* g++.dg/torture/pr83471.C: New test.

From-SVN: r255821

gcc/testsuite/ChangeLog

+2017-12-19  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR middle-end/83471
+	* g++.dg/torture/pr83471.C: New test.
+
 2017-12-19  Martin Liska  <mliska@suse.cz>
 
 	* gcc.dg/tree-prof/switch-case-1.c: Scan IPA profile dump

gcc/testsuite/g++.dg/torture/pr83471.C

+/* { dg-do compile } */
+
+class a {
+public:
+  void *operator new(__SIZE_TYPE__, int);
+};
+class b : public a {
+public:
+  b();
+  virtual void c() {}
+  void m_fn2();
+};
+int d;
+void e() {
+  long f;
+  b *g;
+  (f);
+  g = new (d) b;
+  g->c();
+  g->m_fn2();
+}