Implement N4295 fold-expressions.

	* cp-tree.def: Add UNARY_LEFT_FOLD_EXPR, UNARY_RIGHT_FOLD_EXPR,
	BINARY_LEFT_FOLD_EXPR, BINARY_RIGHT_FOLD_EXPR.
	* cp-objcp-common.c (cp_common_init_ts): Handle them.
	* cp-tree.h (FOLD_EXPR_CHECK, BINARY_FOLD_EXPR_CHECK, FOLD_EXPR_P)
	(FOLD_EXPR_MODIFY_P, FOLD_EXPR_OP, FOLD_EXPR_PACK, FOLD_EXPR_INIT): New.
	* parser.c (cp_parser_skip_to_closing_parenthesis): Split out...
	(cp_parser_skip_to_closing_parenthesis_1): This function.  Change
	or_comma parameter to or_ttype.
	(cp_parser_fold_operator, cp_parser_fold_expr_p)
	(cp_parser_fold_expression): New.
	(cp_parser_primary_expression): Use them.
	* pt.c (expand_empty_fold, fold_expression, tsubst_fold_expr_pack)
	(tsubst_fold_expr_init, expand_left_fold, tsubst_unary_left_fold)
	(tsubst_binary_left_fold, expand_right_fold)
	(tsubst_unary_right_fold, tsubst_binary_right_fold): New.
	(tsubst_copy): Use them.
	(type_dependent_expression_p): Handle fold-expressions.
	* semantics.c (finish_unary_fold_expr)
	(finish_left_unary_fold_expr, finish_right_unary_fold_expr)
	(finish_binary_fold_expr): New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@227883 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 36 insertions, 0 deletions

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 8643e089d03..80d6c4e4a2f 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -80,6 +80,7 @@ c-common.h, not after.
       COMPOUND_REQ_NOEXCEPT_P (in COMPOUND_REQ)
       WILDCARD_PACK_P (in WILDCARD_DECL)
       BLOCK_OUTER_CURLY_BRACE_P (in BLOCK)
+      FOLD_EXPR_MODOP_P (*_FOLD_EXPR)
    1: IDENTIFIER_VIRTUAL_P (in IDENTIFIER_NODE)
       TI_PENDING_TEMPLATE_FLAG.
       TEMPLATE_PARMS_FOR_INLINE.
@@ -3249,6 +3250,37 @@ extern void decl_shadowed_for_var_insert (tree, tree);
   TREE_VEC_ELT (ARGUMENT_PACK_ARGS (ARGUMENT_PACK_SELECT_FROM_PACK (NODE)), \
 	        ARGUMENT_PACK_SELECT_INDEX (NODE))
 
+#define FOLD_EXPR_CHECK(NODE)						\
+  TREE_CHECK4 (NODE, UNARY_LEFT_FOLD_EXPR, UNARY_RIGHT_FOLD_EXPR,	\
+	       BINARY_LEFT_FOLD_EXPR, BINARY_RIGHT_FOLD_EXPR)
+
+#define BINARY_FOLD_EXPR_CHECK(NODE) \
+  TREE_CHECK2 (NODE, BINARY_LEFT_FOLD_EXPR, BINARY_RIGHT_FOLD_EXPR)
+
+/* True if NODE is UNARY_FOLD_EXPR or a BINARY_FOLD_EXPR */
+#define FOLD_EXPR_P(NODE) \
+  TREE_CODE (NODE) == UNARY_LEFT_FOLD_EXPR \
+    || TREE_CODE (NODE) == UNARY_RIGHT_FOLD_EXPR \
+    || TREE_CODE (NODE) == BINARY_LEFT_FOLD_EXPR \
+    || TREE_CODE (NODE) == BINARY_RIGHT_FOLD_EXPR
+
+/* True when NODE is a fold over a compound assignment operator. */
+#define FOLD_EXPR_MODIFY_P(NODE) \
+  TREE_LANG_FLAG_0 (FOLD_EXPR_CHECK (NODE))
+
+/* An INTEGER_CST containing the tree code of the folded operator. */
+#define FOLD_EXPR_OP(NODE) \
+  TREE_OPERAND (FOLD_EXPR_CHECK (NODE), 0)
+
+/* The expression containing an unexpanded parameter pack. */
+#define FOLD_EXPR_PACK(NODE) \
+  TREE_OPERAND (FOLD_EXPR_CHECK (NODE), 1)
+
+/* In a binary fold expression, the argument with no unexpanded
+   parameter packs. */
+#define FOLD_EXPR_INIT(NODE) \
+  TREE_OPERAND (BINARY_FOLD_EXPR_CHECK (NODE), 2)
+
 /* In a FUNCTION_DECL, the saved language-specific per-function data.  */
 #define DECL_SAVED_FUNCTION_DATA(NODE)			\
   (LANG_DECL_FN_CHECK (FUNCTION_DECL_CHECK (NODE))	\
@@ -6567,6 +6599,10 @@ extern bool check_literal_operator_args		(const_tree, bool *, bool *);
 extern void maybe_warn_about_useless_cast       (tree, tree, tsubst_flags_t);
 extern tree cp_perform_integral_promotions      (tree, tsubst_flags_t);
 
+extern tree finish_left_unary_fold_expr      (tree, int);
+extern tree finish_right_unary_fold_expr     (tree, int);
+extern tree finish_binary_fold_expr          (tree, tree, int);
+
 /* in typeck2.c */
 extern void require_complete_eh_spec_types	(tree, tree);
 extern void cxx_incomplete_type_diagnostic	(const_tree, const_tree, diagnostic_t);