constexpr.c (potential_nondependent_constant_expression): New.

* constexpr.c (potential_nondependent_constant_expression): New.
	(potential_nondependent_static_init_expression): New.
	(maybe_constant_value_1, fold_non_dependent_expr)
	(maybe_constant_init): Use them.
	* pt.c (instantiate_non_dependent_expr_sfinae)
	(instantiate_non_dependent_or_null, convert_nontype_argument): Use
	them.
	* cp-tree.h: Declare them.

From-SVN: r234944

gcc/cp/ChangeLog

@@ -1,3 +1,14 @@
+2016-04-13  Jason Merrill  <jason@redhat.com>
+
+	* constexpr.c (potential_nondependent_constant_expression): New.
+	(potential_nondependent_static_init_expression): New.
+	(maybe_constant_value_1, fold_non_dependent_expr)
+	(maybe_constant_init): Use them.
+	* pt.c (instantiate_non_dependent_expr_sfinae)
+	(instantiate_non_dependent_or_null, convert_nontype_argument): Use
+	them.
+	* cp-tree.h: Declare them.
+
 2016-04-13  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/70594

gcc/cp/constexpr.c

@@ -4315,10 +4315,7 @@ maybe_constant_value_1 (tree t, tree decl)
 {
   tree r;
 
-  if (instantiation_dependent_expression_p (t)
+  if (!potential_nondependent_constant_expression (t))
-      || type_unknown_p (t)
-      || BRACE_ENCLOSED_INITIALIZER_P (t)
-      || !potential_constant_expression (t))
     {
       if (TREE_OVERFLOW_P (t))
 	{
@@ -4397,8 +4394,7 @@ fold_non_dependent_expr (tree t)
      as two declarations of the same function, for example.  */
   if (processing_template_decl)
     {
-      if (!instantiation_dependent_expression_p (t)
+      if (potential_nondependent_constant_expression (t))
-	  && potential_constant_expression (t))
 	{
 	  processing_template_decl_sentinel s;
 	  t = instantiate_non_dependent_expr_internal (t, tf_none);
@@ -4449,10 +4445,7 @@ maybe_constant_init (tree t, tree decl)
     t = TREE_OPERAND (t, 0);
   if (TREE_CODE (t) == INIT_EXPR)
     t = TREE_OPERAND (t, 1);
-  if (instantiation_dependent_expression_p (t)
+  if (!potential_nondependent_static_init_expression (t))
-      || type_unknown_p (t)
-      || BRACE_ENCLOSED_INITIALIZER_P (t)
-      || !potential_static_init_expression (t))
     /* Don't try to evaluate it.  */;
   else
     t = cxx_eval_outermost_constant_expr (t, true, false, decl);
@@ -5203,4 +5196,29 @@ require_potential_rvalue_constant_expression (tree t)
   return potential_constant_expression_1 (t, true, true, tf_warning_or_error);
 }
 
+/* Returns true if T is a potential constant expression that is not
+   instantiation-dependent, and therefore a candidate for constant folding even
+   in a template.  */
+
+bool
+potential_nondependent_constant_expression (tree t)
+{
+  return (!type_unknown_p (t)
+	  && !BRACE_ENCLOSED_INITIALIZER_P (t)
+	  && potential_constant_expression (t)
+	  && !instantiation_dependent_expression_p (t));
+}
+
+/* Returns true if T is a potential static initializer expression that is not
+   instantiation-dependent.  */
+
+bool
+potential_nondependent_static_init_expression (tree t)
+{
+  return (!type_unknown_p (t)
+	  && !BRACE_ENCLOSED_INITIALIZER_P (t)
+	  && potential_static_init_expression (t)
+	  && !instantiation_dependent_expression_p (t));
+}
+
 #include "gt-cp-constexpr.h"

gcc/cp/cp-tree.h

@@ -6884,6 +6884,8 @@ extern tree register_constexpr_fundef           (tree, tree);
 extern bool check_constexpr_ctor_body           (tree, tree, bool);
 extern tree ensure_literal_type_for_constexpr_object (tree);
 extern bool potential_constant_expression       (tree);
+extern bool potential_nondependent_constant_expression (tree);
+extern bool potential_nondependent_static_init_expression (tree);
 extern bool potential_static_init_expression    (tree);
 extern bool potential_rvalue_constant_expression (tree);
 extern bool require_potential_constant_expression (tree);

gcc/cp/pt.c

@@ -5655,8 +5655,7 @@ instantiate_non_dependent_expr_sfinae (tree expr, tsubst_flags_t complain)
 
      as two declarations of the same function, for example.  */
   if (processing_template_decl
-      && !instantiation_dependent_expression_p (expr)
+      && potential_nondependent_constant_expression (expr))
-      && potential_constant_expression (expr))
     {
       processing_template_decl_sentinel s;
       expr = instantiate_non_dependent_expr_internal (expr, complain);
@@ -5680,8 +5679,7 @@ instantiate_non_dependent_or_null (tree expr)
     return NULL_TREE;
   if (processing_template_decl)
     {
-      if (instantiation_dependent_expression_p (expr)
+      if (!potential_nondependent_constant_expression (expr))
-	  || !potential_constant_expression (expr))
 	expr = NULL_TREE;
       else
 	{
@@ -6240,10 +6238,8 @@ convert_nontype_argument (tree type, tree expr, tsubst_flags_t complain)
   if (TYPE_REF_OBJ_P (type)
       && has_value_dependent_address (expr))
     /* If we want the address and it's value-dependent, don't fold.  */;
-  else if (!type_unknown_p (expr)
+  else if (processing_template_decl
-	   && processing_template_decl
+	   && potential_nondependent_constant_expression (expr))
-	   && !instantiation_dependent_expression_p (expr)
-	   && potential_constant_expression (expr))
     non_dep = true;
   if (error_operand_p (expr))
     return error_mark_node;