re PR c++/84927 (ICE with NSDMI and reference)

	PR c++/84927
	* constexpr.c (cxx_eval_bare_aggregate): Update constructor's flags
	as we evaluate the elements.
	(cxx_eval_constant_expression): Verify constructor's flags
	unconditionally.

	* g++.dg/cpp1y/nsdmi-aggr9.C: New test.

From-SVN: r258661

gcc/cp/ChangeLog

@@ -3,6 +3,12 @@
 	PR c++/84925
 	* pt.c (enclosing_instantiation_of): Check if fn is null.
 
+	PR c++/84927
+	* constexpr.c (cxx_eval_bare_aggregate): Update constructor's flags
+	as we evaluate the elements.
+	(cxx_eval_constant_expression): Verify constructor's flags
+	unconditionally.
+
 2018-03-16  Jason Merrill  <jason@redhat.com>
 
 	PR c++/71834 - template-id with too few arguments.

gcc/cp/constexpr.c

@@ -2880,7 +2880,12 @@ cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t,
 	  (*p)->last().value = elt;
 	}
       else
-	CONSTRUCTOR_APPEND_ELT (*p, index, elt);
+	{
+	  CONSTRUCTOR_APPEND_ELT (*p, index, elt);
+	  /* Adding an element might change the ctor's flags.  */
+	  TREE_CONSTANT (ctx->ctor) = constant_p;
+	  TREE_SIDE_EFFECTS (ctx->ctor) = side_effects_p;
+	}
     }
   if (*non_constant_p || !changed)
     return t;
@@ -4530,11 +4535,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
 	{
 	  /* Don't re-process a constant CONSTRUCTOR, but do fold it to
 	     VECTOR_CST if applicable.  */
-	  /* FIXME after GCC 6 branches, make the verify unconditional.  */
-	  if (CHECKING_P)
-	    verify_constructor_flags (t);
-	  else
-	    recompute_constructor_flags (t);
+	  verify_constructor_flags (t);
 	  if (TREE_CONSTANT (t))
 	    return fold (t);
 	}

gcc/testsuite/ChangeLog

@@ -3,6 +3,9 @@
 	PR c++/84925
 	* g++.dg/cpp1z/lambda-__func__.C: New test.
 
+	PR c++/84927
+	* g++.dg/cpp1y/nsdmi-aggr9.C: New test.
+
 2018-03-19  Maxim Ostapenko  <m.ostapenko@samsung.com>
 
 	PR sanitizer/78651

gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr9.C

+// PR c++/84927 - ICE with NSDMI and reference
+// { dg-do compile { target c++14 } }
+
+struct A
+{
+  int& r;
+  int i = r;
+};
+
+void foo()
+{
+  int j;
+  A a = A{j};
+}