PR c++/80077 - error with constexpr and -fno-elide-constructors.

	* constexpr.c (cxx_eval_call_expression): Set ctx->call while
	expanding trivial constructor.

From-SVN: r246272

gcc/cp/ChangeLog

+2017-03-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/80077 - error with constexpr and -fno-elide-constructors.
+	* constexpr.c (cxx_eval_call_expression): Set ctx->call while
+	expanding trivial constructor.
+
 2017-03-17  Jason Merrill  <jason@redhat.com>
 
 	PR c++/78345 - ICE initializing array from lambda.

gcc/cp/constexpr.c

@@ -1478,7 +1478,8 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
 	  else
 	    op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op);
 	  tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init);
-	  return cxx_eval_constant_expression (ctx, set, lval,
+	  new_ctx.call = &new_call;
+	  return cxx_eval_constant_expression (&new_ctx, set, lval,
 					       non_constant_p, overflow_p);
 	}
     }
@@ -1496,7 +1497,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
     }
 
   /* If in direct recursive call, optimize definition search.  */
-  if (ctx && ctx->call && ctx->call->fundef->decl == fun)
+  if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun)
     new_call.fundef = ctx->call->fundef;
   else
     {

gcc/testsuite/g++.dg/cpp0x/constexpr-trivial3.C

+// PR c++/80077
+// { dg-do compile { target c++11 } }
+// { dg-options -fno-elide-constructors }
+
+struct X_t { X_t() = default; };
+constexpr X_t x = X_t();