PR c++/71711 - mangle C++1z fold-expressions.

	* operators.def: Add *_FOLD_EXPR.
	* cp-tree.h (FOLD_EXPR_P): Parenthesize.
	* mangle.c (write_expression): Handle fold-expressions.
	* pt.c (tsubst_unary_left_fold, tsubst_binary_left_fold)
	(tsubst_unary_right_fold, tsubst_binary_right_fold): Handle
	partial instantiation.

From-SVN: r238390

gcc/cp/ChangeLog

 2016-07-15  Jason Merrill  <jason@redhat.com>
 
+	PR c++/71711
+	* operators.def: Add *_FOLD_EXPR.
+	* cp-tree.h (FOLD_EXPR_P): Parenthesize.
+	* mangle.c (write_expression): Handle fold-expressions.
+	* pt.c (tsubst_unary_left_fold, tsubst_binary_left_fold)
+	(tsubst_unary_right_fold, tsubst_binary_right_fold): Handle
+	partial instantiation.
+
 	PR c++/71814
 	* mangle.c (write_expression): Handle sizeof... an argument pack.
 

gcc/cp/cp-tree.h

@@ -3334,11 +3334,11 @@ extern void decl_shadowed_for_var_insert (tree, tree);
   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
+#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) \

gcc/cp/mangle.c

@@ -3145,6 +3145,29 @@ write_expression (tree expr)
 			 "cannot be mangled");
 		  continue;
 		}
+	      else if (FOLD_EXPR_P (expr))
+		{
+		  /* The first 'operand' of a fold-expression is the operator
+		     that it folds over.  */
+		  if (i == 0)
+		    {
+		      int fcode = TREE_INT_CST_LOW (operand);
+		      write_string (operator_name_info[fcode].mangled_name);
+		      continue;
+		    }
+		  else if (code == BINARY_LEFT_FOLD_EXPR)
+		    {
+		      /* The order of operands of the binary left and right
+			 folds is the same, but we want to mangle them in
+			 lexical order, i.e. non-pack first.  */
+		      if (i == 1)
+			operand = FOLD_EXPR_INIT (expr);
+		      else
+			operand = FOLD_EXPR_PACK (expr);
+		    }
+		  if (PACK_EXPANSION_P (operand))
+		    operand = PACK_EXPANSION_PATTERN (operand);
+		}
 	      write_expression (operand);
 	    }
 	}

gcc/cp/operators.def

@@ -155,3 +155,7 @@ DEF_SIMPLE_OPERATOR ("()", CALL_EXPR, "cl", -1)
 
 /* Variadic templates extension. */
 DEF_SIMPLE_OPERATOR ("...", EXPR_PACK_EXPANSION, "sp", 1)
+DEF_SIMPLE_OPERATOR ("... +", UNARY_LEFT_FOLD_EXPR, "fl", 2)
+DEF_SIMPLE_OPERATOR ("+ ...", UNARY_RIGHT_FOLD_EXPR, "fr", 2)
+DEF_SIMPLE_OPERATOR ("+ ... +", BINARY_LEFT_FOLD_EXPR, "fL", 3)
+DEF_SIMPLE_OPERATOR ("+ ... +", BINARY_RIGHT_FOLD_EXPR, "fR", 3)

gcc/cp/pt.c

@@ -10791,6 +10791,12 @@ tsubst_unary_left_fold (tree t, tree args, tsubst_flags_t complain,
   tree pack = tsubst_fold_expr_pack (t, args, complain, in_decl);
   if (pack == error_mark_node)
     return error_mark_node;
+  if (PACK_EXPANSION_P (pack))
+    {
+      tree r = copy_node (t);
+      FOLD_EXPR_PACK (r) = pack;
+      return r;
+    }
   if (TREE_VEC_LENGTH (pack) == 0)
     return expand_empty_fold (t, complain);
   else
@@ -10813,6 +10819,14 @@ tsubst_binary_left_fold (tree t, tree args, tsubst_flags_t complain,
   if (init == error_mark_node)
     return error_mark_node;
 
+  if (PACK_EXPANSION_P (pack))
+    {
+      tree r = copy_node (t);
+      FOLD_EXPR_PACK (r) = pack;
+      FOLD_EXPR_INIT (r) = init;
+      return r;
+    }
+
   tree vec = make_tree_vec (TREE_VEC_LENGTH (pack) + 1);
   TREE_VEC_ELT (vec, 0) = init;
   for (int i = 0; i < TREE_VEC_LENGTH (pack); ++i)
@@ -10854,6 +10868,12 @@ tsubst_unary_right_fold (tree t, tree args, tsubst_flags_t complain,
   tree pack = tsubst_fold_expr_pack (t, args, complain, in_decl);
   if (pack == error_mark_node)
     return error_mark_node;
+  if (PACK_EXPANSION_P (pack))
+    {
+      tree r = copy_node (t);
+      FOLD_EXPR_PACK (r) = pack;
+      return r;
+    }
   if (TREE_VEC_LENGTH (pack) == 0)
     return expand_empty_fold (t, complain);
   else
@@ -10876,6 +10896,14 @@ tsubst_binary_right_fold (tree t, tree args, tsubst_flags_t complain,
   if (init == error_mark_node)
     return error_mark_node;
 
+  if (PACK_EXPANSION_P (pack))
+    {
+      tree r = copy_node (t);
+      FOLD_EXPR_PACK (r) = pack;
+      FOLD_EXPR_INIT (r) = init;
+      return r;
+    }
+
   int n = TREE_VEC_LENGTH (pack);
   tree vec = make_tree_vec (n + 1);
   for (int i = 0; i < n; ++i)

gcc/testsuite/g++.dg/cpp1z/fold-mangle.C

+// PR c++/71711
+// { dg-options -std=c++1z }
+
+template < int > struct A {};
+template < int ... N > void unary_left (A < (... + N) >);
+template < int ... N > void unary_right (A < (N + ...) >);
+template < int ... N > void binary_left (A < (42 + ... + N) >);
+template < int ... N > void binary_right (A < (N + ... + 42) >);
+
+void bar ()  
+{
+  // { dg-final { scan-assembler "_Z10unary_leftIJLi1ELi2ELi3EEEv1AIXflplT_EE" } }
+  unary_left < 1, 2, 3 > ({});
+  // { dg-final { scan-assembler "_Z11unary_rightIJLi1ELi2ELi3EEEv1AIXfrplT_EE" } }
+  unary_right < 1, 2, 3 > ({});
+  // { dg-final { scan-assembler "_Z11binary_leftIJLi1ELi2ELi3EEEv1AIXfLplLi42ET_EE" } }
+  binary_left < 1, 2, 3 > ({});
+  // { dg-final { scan-assembler "_Z12binary_rightIJLi1ELi2ELi3EEEv1AIXfRplT_Li42EEE" } }
+  binary_right < 1, 2, 3 > ({});
+}