Fix various latent issues revealed by P0732 work.

The initialized_type hunk fixes handling of void AGGR_INIT_EXPRs that call a
non-constructor; an AGGR_INIT_EXPR can have void type if its initialization
semantics are more complicated than just expanding the call.

The cxx_eval_vec_init_1 hunk corrects AGGR_INIT_EXPRs that were
nonsensically built to initialize an object of void type.  And the
build_aggr_init_expr hunk makes sure we don't do that again.

The ocp_convert and cxx_eval_outermost_constant_expr hunks deal with making
sure that a constant CONSTRUCTOR has the right type.

	* cvt.c (ocp_convert): Don't wrap a CONSTRUCTOR in a NOP_EXPR.
	* constexpr.c (initialized_type): Fix AGGR_INIT_EXPR handling.
	(cxx_eval_vec_init_1): Correct type of AGGR_INIT_EXPR.
	(cxx_eval_outermost_constant_expr): Make sure a CONSTRUCTOR has the
	right type.  Don't wrap a CONSTRUCTOR if one was passed in.
	* tree.c (build_aggr_init_expr): Check for void.

From-SVN: r265788

gcc/cp/ChangeLog

@@ -1,5 +1,12 @@
 2018-11-04  Jason Merrill  <jason@redhat.com>
 
+	* cvt.c (ocp_convert): Don't wrap a CONSTRUCTOR in a NOP_EXPR.
+	* constexpr.c (initialized_type): Fix AGGR_INIT_EXPR handling.
+	(cxx_eval_vec_init_1): Correct type of AGGR_INIT_EXPR.
+	(cxx_eval_outermost_constant_expr): Make sure a CONSTRUCTOR has the
+	right type.  Don't wrap a CONSTRUCTOR if one was passed in.
+	* tree.c (build_aggr_init_expr): Check for void.
+
 	PR c++/60503 - wrong lambda attribute syntax.
 	* parser.c (cp_parser_lambda_declarator_opt): Fix attribute
 	handling.

gcc/cp/constexpr.c

@@ -2778,8 +2778,10 @@ initialized_type (tree t)
 {
   if (TYPE_P (t))
     return t;
-  tree type = cv_unqualified (TREE_TYPE (t));
-  if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR)
+  tree type = TREE_TYPE (t);
+  if (!VOID_TYPE_P (type))
+    /* No need to look deeper.  */;
+  else if (TREE_CODE (t) == CALL_EXPR)
     {
       /* A constructor call has void type, so we need to look deeper.  */
       tree fn = get_function_named_in_call (t);
@@ -2787,7 +2789,9 @@ initialized_type (tree t)
 	  && DECL_CXX_CONSTRUCTOR_P (fn))
 	type = DECL_CONTEXT (fn);
     }
-  return type;
+  else if (TREE_CODE (t) == AGGR_INIT_EXPR)
+    type = TREE_TYPE (AGGR_INIT_EXPR_SLOT (t));
+  return cv_unqualified (type);
 }
 
 /* We're about to initialize element INDEX of an array or class from VALUE.
@@ -3000,7 +3004,7 @@ cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init,
 					&argvec, elttype, LOOKUP_NORMAL,
 					complain);
       release_tree_vector (argvec);
-      init = build_aggr_init_expr (TREE_TYPE (init), init);
+      init = build_aggr_init_expr (elttype, init);
       pre_init = true;
     }
 
@@ -5089,7 +5093,7 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant,
 	r = build_nop (TREE_TYPE (r), r);
       TREE_CONSTANT (r) = false;
     }
-  else if (non_constant_p || r == t)
+  else if (non_constant_p)
     return t;
 
   if (should_unshare)
@@ -5097,18 +5101,18 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant,
 
   if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r)))
     {
+      r = adjust_temp_type (type, r);
       if (TREE_CODE (t) == TARGET_EXPR
 	  && TARGET_EXPR_INITIAL (t) == r)
 	return t;
-      else
+      else if (TREE_CODE (t) != CONSTRUCTOR)
 	{
 	  r = get_target_expr (r);
 	  TREE_CONSTANT (r) = true;
-	  return r;
 	}
     }
-  else
-    return r;
+
+  return r;
 }
 
 /* Returns true if T is a valid subexpression of a constant expression,

gcc/cp/cvt.c

@@ -725,7 +725,8 @@ ocp_convert (tree type, tree expr, int convtype, int flags,
     /* We need a new temporary; don't take this shortcut.  */;
   else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e)))
     {
-      if (same_type_p (type, TREE_TYPE (e)))
+      tree etype = TREE_TYPE (e);
+      if (same_type_p (type, etype))
 	/* The call to fold will not always remove the NOP_EXPR as
 	   might be expected, since if one of the types is a typedef;
 	   the comparison in fold is just equality of pointers, not a
@@ -743,9 +744,16 @@ ocp_convert (tree type, tree expr, int convtype, int flags,
 	{
 	  /* Don't build a NOP_EXPR of class type.  Instead, change the
 	     type of the temporary.  */
+	  gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, etype));
 	  TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type;
 	  return e;
 	}
+      else if (TREE_CODE (e) == CONSTRUCTOR)
+	{
+	  gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, etype));
+	  TREE_TYPE (e) = type;
+	  return e;
+	}
       else
 	{
 	  /* We shouldn't be treating objects of ADDRESSABLE type as

gcc/cp/tree.c

@@ -576,6 +576,8 @@ build_aggr_init_expr (tree type, tree init)
   tree rval;
   int is_ctor;
 
+  gcc_assert (!VOID_TYPE_P (type));
+
   /* Don't build AGGR_INIT_EXPR in a template.  */
   if (processing_template_decl)
     return init;