re PR c++/88110 (ICE (segfault) with -std=C++2a in cxx_eval_constant_expression…

re PR c++/88110 (ICE (segfault) with -std=C++2a in cxx_eval_constant_expression when trying to evaluate nonoverridden "virtual ... = 0" function of a base class)

	PR c++/88110
	* constexpr.c (cxx_eval_constant_expression) <case OBJ_TYPE_REF>: Punt
	if get_base_address of ADDR_EXPR operand is not a DECL_P.

	* g++.dg/cpp2a/constexpr-virtual13.C: New test.

From-SVN: r266329

gcc/cp/ChangeLog

+2018-11-20  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/88110
+	* constexpr.c (cxx_eval_constant_expression) <case OBJ_TYPE_REF>: Punt
+	if get_base_address of ADDR_EXPR operand is not a DECL_P.
+
 2018-11-19  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/87781 - detect invalid elaborated-type-specifier.

gcc/cp/constexpr.c

@@ -4815,7 +4815,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
 	obj = cxx_eval_constant_expression (ctx, obj, lval, non_constant_p,
 					    overflow_p);
 	/* We expect something in the form of &x.D.2103.D.2094; get x. */
-	if (TREE_CODE (obj) != ADDR_EXPR)
+	if (TREE_CODE (obj) != ADDR_EXPR
+	    || !DECL_P (get_base_address (TREE_OPERAND (obj, 0))))
 	  {
 	    if (!ctx->quiet)
 	      error_at (cp_expr_loc_or_loc (t, input_location),

gcc/testsuite/ChangeLog

 2018-11-20  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/88110
+	* g++.dg/cpp2a/constexpr-virtual13.C: New test.
+
 	PR tree-optimization/87895
 	* gcc.dg/gomp/pr87895-1.c: New test.
 	* gcc.dg/gomp/pr87895-2.c: New test.

gcc/testsuite/g++.dg/cpp2a/constexpr-virtual13.C

+// PR c++/88110
+// { dg-do compile }
+
+struct A {
+  virtual int foo () const = 0;
+};
+struct B {
+  virtual int bar () const = 0;
+  virtual int baz () const = 0;
+};
+struct C : public A { };
+struct D : public C { };
+struct E : public D, public B { };
+
+void
+qux (const E *x)
+{
+  if (x->baz ())
+    ;
+}