[C++ PATCH] deferred noexcept spec

[Nathan Sidwell <nathan@acm.org>]

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We defer creating the deferred noexept spec.  That's somewhat more 
deferred than necessary.  This patch creates the defered spec at the 
point we create the noexcept true and false specs.

Applied to trunk.

nathan
-- 
Nathan Sidwell

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2017-06-16  Nathan Sidwell  <nathan@acm.org>

	Don't defer noexcept_deferred_spec.
	* cp-tree.h (unevaluated_noexcept_spec): Don't declare.
	(cxx_init_decl_processing): Initialize noexcept_deferred_spec.
	* except.c (unevaluated_noexcept_spec): Delete.
	* class.c (deduce_noexcept_on_destructor): Use
	noexcept_deferred_spec directly.
	* method.c (implicitly_declare_fn): Likewise.

Index: class.c
===================================================================
--- class.c	(revision 249263)
+++ class.c	(working copy)
@@ -5025,10 +5025,8 @@ void
 deduce_noexcept_on_destructor (tree dtor)
 {
   if (!TYPE_RAISES_EXCEPTIONS (TREE_TYPE (dtor)))
-    {
-      tree eh_spec = unevaluated_noexcept_spec ();
-      TREE_TYPE (dtor) = build_exception_variant (TREE_TYPE (dtor), eh_spec);
-    }
+    TREE_TYPE (dtor) = build_exception_variant (TREE_TYPE (dtor),
+						noexcept_deferred_spec);
 }
 
 /* For each destructor in T, deduce noexcept:
Index: cp-tree.h
===================================================================
--- cp-tree.h	(revision 249263)
+++ cp-tree.h	(working copy)
@@ -6317,7 +6317,6 @@ extern tree forward_parm			(tree);
 extern bool is_trivially_xible			(enum tree_code, tree, tree);
 extern bool is_xible				(enum tree_code, tree, tree);
 extern tree get_defaulted_eh_spec		(tree);
-extern tree unevaluated_noexcept_spec		(void);
 extern void after_nsdmi_defaulted_late_checks   (tree);
 extern bool maybe_explain_implicit_delete	(tree);
 extern void explain_implicit_non_constexpr	(tree);
Index: decl.c
===================================================================
--- decl.c	(revision 249263)
+++ decl.c	(working copy)
@@ -4078,6 +4078,8 @@ cxx_init_decl_processing (void)
   empty_except_spec = build_tree_list (NULL_TREE, NULL_TREE);
   noexcept_true_spec = build_tree_list (boolean_true_node, NULL_TREE);
   noexcept_false_spec = build_tree_list (boolean_false_node, NULL_TREE);
+  noexcept_deferred_spec = build_tree_list (make_node (DEFERRED_NOEXCEPT),
+					    NULL_TREE);
 
 #if 0
   record_builtin_type (RID_MAX, NULL, string_type_node);
Index: except.c
===================================================================
--- except.c	(revision 249255)
+++ except.c	(working copy)
@@ -1197,18 +1197,6 @@ build_noexcept_spec (tree expr, int comp
     }
 }
 
-/* Returns a noexcept-specifier to be evaluated later, for an
-   implicitly-declared or explicitly defaulted special member function.  */
-
-tree
-unevaluated_noexcept_spec (void)
-{
-  if (!noexcept_deferred_spec)
-    noexcept_deferred_spec
-      = build_noexcept_spec (make_node (DEFERRED_NOEXCEPT), tf_none);
-  return noexcept_deferred_spec;
-}
-
 /* Returns a TRY_CATCH_EXPR that will put TRY_LIST and CATCH_LIST in the
    TRY and CATCH locations.  CATCH_LIST must be a STATEMENT_LIST */
 
Index: method.c
===================================================================
--- method.c	(revision 249255)
+++ method.c	(working copy)
@@ -2023,7 +2023,7 @@ implicitly_declare_fn (special_function_
     }
   else if (cxx_dialect >= cxx11)
     {
-      raises = unevaluated_noexcept_spec ();
+      raises = noexcept_deferred_spec;
       synthesized_method_walk (type, kind, const_p, NULL, &trivial_p,
 			       &deleted_p, &constexpr_p, false,
 			       inherited_ctor, inherited_parms);