c++: various code cleanups

* Harden some tree accessor macros and fix a couple of bad
  PLACEHOLDER_TYPE_CONSTRAINTS accesses uncovered by this.
* Use strip_innermost_template_args in outer_template_args.
* Add !processing_template_decl early exit tests to some dependence
  predicates.

gcc/cp/ChangeLog:

	* cp-tree.h (PLACEHOLDER_TYPE_CONSTRAINTS_INFO): Harden via
	TEMPLATE_TYPE_PARM_CHECK.
	(TPARMS_PRIMARY_TEMPLATE): Harden via TREE_VEC_CHECK.
	(TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL): Harden via
	TEMPLATE_TEMPLATE_PARM_CHECK.
	* cxx-pretty-print.cc (cxx_pretty_printer::simple_type_specifier):
	Guard PLACEHOLDER_TYPE_CONSTRAINTS access.
	* error.cc (dump_type) <case TEMPLATE_TYPE_PARM>: Use separate
	variable to store CLASS_PLACEHOLDER_TEMPLATE result.
	* pt.cc (outer_template_args): Use strip_innermost_template_args.
	(any_type_dependent_arguments_p): Exit early if
	!processing_template_decl.  Use range-based for.
	(any_dependent_template_arguments_p): Likewise.

4 files changed, 20 insertions, 25 deletions

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 406a550..714b6d5 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -1636,7 +1636,7 @@ check_constraint_info (tree t)
    holds the set of template parameters that were in-scope when this 'auto'
    was formed.  */
 #define PLACEHOLDER_TYPE_CONSTRAINTS_INFO(NODE) \
-  DECL_SIZE_UNIT (TYPE_NAME (NODE))
+  DECL_SIZE_UNIT (TYPE_NAME (TEMPLATE_TYPE_PARM_CHECK (NODE)))
 
 /* The constraints on the 'auto' placeholder type NODE.  */
 #define PLACEHOLDER_TYPE_CONSTRAINTS(NODE)		   \
@@ -5084,7 +5084,7 @@ get_vec_init_expr (tree t)
    templates are primary, too.  */
 
 /* Returns the primary template corresponding to these parameters.  */
-#define TPARMS_PRIMARY_TEMPLATE(NODE) (TREE_TYPE (NODE))
+#define TPARMS_PRIMARY_TEMPLATE(NODE) (TREE_TYPE (TREE_VEC_CHECK (NODE)))
 
 #define DECL_PRIMARY_TEMPLATE(NODE) \
   (TPARMS_PRIMARY_TEMPLATE (DECL_INNERMOST_TEMPLATE_PARMS (NODE)))
@@ -6098,7 +6098,7 @@ const unsigned int STF_STRIP_DEPENDENT = 1U << 1;
 #define TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL(NODE)	\
   ((TREE_CODE (NODE) == BOUND_TEMPLATE_TEMPLATE_PARM)	\
    ? TYPE_TI_TEMPLATE (NODE)				\
-   : TYPE_NAME (NODE))
+   : TYPE_NAME (TEMPLATE_TEMPLATE_PARM_CHECK (NODE)))
 
 /* in lex.cc  */
 
diff --git a/gcc/cp/cxx-pretty-print.cc b/gcc/cp/cxx-pretty-print.cc
index 4cda27f..950295e 100644
--- a/gcc/cp/cxx-pretty-print.cc
+++ b/gcc/cp/cxx-pretty-print.cc
@@ -1364,8 +1364,9 @@ cxx_pretty_printer::simple_type_specifier (tree t)
     case TEMPLATE_PARM_INDEX:
     case BOUND_TEMPLATE_TEMPLATE_PARM:
       pp_cxx_unqualified_id (this, t);
-      if (tree c = PLACEHOLDER_TYPE_CONSTRAINTS (t))
-        pp_cxx_constrained_type_spec (this, c);
+      if (TREE_CODE (t) == TEMPLATE_TYPE_PARM)
+	if (tree c = PLACEHOLDER_TYPE_CONSTRAINTS (t))
+	  pp_cxx_constrained_type_spec (this, c);
       break;
 
     case TYPENAME_TYPE:
diff --git a/gcc/cp/error.cc b/gcc/cp/error.cc
index a5d8889..1cfa4f1 100644
--- a/gcc/cp/error.cc
+++ b/gcc/cp/error.cc
@@ -639,8 +639,8 @@ dump_type (cxx_pretty_printer *pp, tree t, int flags)
       pp_cxx_cv_qualifier_seq (pp, t);
       if (template_placeholder_p (t))
 	{
-	  t = TREE_TYPE (CLASS_PLACEHOLDER_TEMPLATE (t));
-	  pp_cxx_tree_identifier (pp, TYPE_IDENTIFIER (t));
+	  tree tmpl = TREE_TYPE (CLASS_PLACEHOLDER_TEMPLATE (t));
+	  pp_cxx_tree_identifier (pp, TYPE_IDENTIFIER (tmpl));
 	  pp_string (pp, "<...auto...>");
 	}
       else if (TYPE_IDENTIFIER (t))
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index de95e12..bb4e275 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -4987,9 +4987,7 @@ outer_template_args (tree tmpl)
     return args;
   if (TMPL_ARGS_DEPTH (args) == 1)
     return NULL_TREE;
-  args = copy_node (args);
-  --TREE_VEC_LENGTH (args);
-  return args;
+  return strip_innermost_template_args (args, 1);
 }
 
 /* Update the declared TYPE by doing any lookups which were thought to be
@@ -28634,14 +28632,13 @@ type_dependent_expression_p_push (tree expr)
 bool
 any_type_dependent_arguments_p (const vec<tree, va_gc> *args)
 {
-  unsigned int i;
-  tree arg;
+  if (!processing_template_decl || !args)
+    return false;
+
+  for (tree arg : *args)
+    if (type_dependent_expression_p (arg))
+      return true;
 
-  FOR_EACH_VEC_SAFE_ELT (args, i, arg)
-    {
-      if (type_dependent_expression_p (arg))
-	return true;
-    }
   return false;
 }
 
@@ -28804,19 +28801,16 @@ any_template_arguments_need_structural_equality_p (tree args)
 bool
 any_dependent_template_arguments_p (const_tree args)
 {
-  int i;
-  int j;
-
-  if (!args)
-    return false;
   if (args == error_mark_node)
     return true;
+  if (!processing_template_decl || !args)
+    return false;
 
-  for (i = 0; i < TMPL_ARGS_DEPTH (args); ++i)
+  for (int i = 0, depth = TMPL_ARGS_DEPTH (args); i < depth; ++i)
     {
       const_tree level = TMPL_ARGS_LEVEL (args, i + 1);
-      for (j = 0; j < TREE_VEC_LENGTH (level); ++j)
-	if (dependent_template_arg_p (TREE_VEC_ELT (level, j)))
+      for (tree arg : tree_vec_range (CONST_CAST_TREE (level)))
+	if (dependent_template_arg_p (arg))
 	  return true;
     }