re PR c++/89285 (ICE after casting the this pointer in the constructor in C++17 mode)

	PR c++/89285
	* g++.dg/cpp1y/constexpr-89285-2.C: New test.

From-SVN: r269188

gcc/testsuite/ChangeLog

+2019-02-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/89285
+	* g++.dg/cpp1y/constexpr-89285-2.C: New test.
+
 2019-02-25  Dominique d'Humieres  <dominiq@gcc.gnu.org>
 
 	PR libfortran/89274

gcc/testsuite/g++.dg/cpp1y/constexpr-89285-2.C

+// PR c++/89285
+// { dg-do compile { target c++14 } }
+
+struct A {
+  int a {};
+};
+struct B {
+  int b {};
+  constexpr B (A *x) {
+    int *c = &x->a;
+    while (*c)
+      c = reinterpret_cast<int *>((reinterpret_cast<char *>(c) + *c));
+    *c = reinterpret_cast<char *>(this) - reinterpret_cast<char *>(c);
+  }
+};
+struct C : A {
+  B bar {this};
+};
+
+C foo {};