[gcc r11-4657] c++: cp_tree_equal cleanups

[gcc r11-4657] c++: cp_tree_equal cleanups

[Nathan Sidwell]

https://gcc.gnu.org/g:444655b6f02605ae936426a14ba527795795587b

commit r11-4657-g444655b6f02605ae936426a14ba527795795587b
Author: Nathan Sidwell <nathan@acm.org>
Date:   Tue Nov 3 05:11:42 2020 -0800

    c++: cp_tree_equal cleanups
    
    A couple of small fixes.  I noticed bind_template_template_parms was
    not marking the parm a template parm (this broke some module
    handling).  Debugging CALL_EXPR comparisons led me to refactor
    cp_tree_equal's CALL_EXPR code (and my recent fix to debug printing of
    same).  Finally TREE_VECS are best compared by comp_template_args.  I
    recall that last piece being a left over from fixes during gcc-10.
    I've been using it on the modules branch since then.
    
            gcc/cp/
            * tree.c (bind_template_template_parm): Mark the parm as a
            template parm.
            (cp_tree_equal): Refactor CALL_EXPR.  Use comp_template_args for
            TREE_VECs.

Diff:
---
 gcc/cp/tree.c | 48 ++++++++++++++++++++++++++----------------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 9bc37aca95b..3087c4ab52c 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -2700,6 +2700,7 @@ bind_template_template_parm (tree t, tree newargs)
   t2 = cxx_make_type (BOUND_TEMPLATE_TEMPLATE_PARM);
   decl = build_decl (input_location,
 		     TYPE_DECL, DECL_NAME (decl), NULL_TREE);
+  SET_DECL_TEMPLATE_PARM_P (decl);
 
   /* These nodes have to be created to reflect new TYPE_DECL and template
      arguments.  */
@@ -3671,20 +3672,28 @@ cp_tree_equal (tree t1, tree t2)
 
     case CALL_EXPR:
       {
-	tree arg1, arg2;
-	call_expr_arg_iterator iter1, iter2;
-	if (KOENIG_LOOKUP_P (t1) != KOENIG_LOOKUP_P (t2)
-	    || !called_fns_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
+	if (KOENIG_LOOKUP_P (t1) != KOENIG_LOOKUP_P (t2))
 	  return false;
-	for (arg1 = first_call_expr_arg (t1, &iter1),
-	       arg2 = first_call_expr_arg (t2, &iter2);
-	     arg1 && arg2;
-	     arg1 = next_call_expr_arg (&iter1),
-	       arg2 = next_call_expr_arg (&iter2))
-	  if (!cp_tree_equal (arg1, arg2))
-	    return false;
-	if (arg1 || arg2)
+
+	if (!called_fns_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
+	  return false;
+
+	call_expr_arg_iterator iter1, iter2;
+	init_call_expr_arg_iterator (t1, &iter1);
+	init_call_expr_arg_iterator (t2, &iter2);
+	if (iter1.n != iter2.n)
 	  return false;
+
+	while (more_call_expr_args_p (&iter1))
+	  {
+	    tree arg1 = next_call_expr_arg (&iter1);
+	    tree arg2 = next_call_expr_arg (&iter2);
+
+	    gcc_checking_assert (arg1 && arg2);
+	    if (!cp_tree_equal (arg1, arg2))
+	      return false;
+	  }
+
 	return true;
       }
 
@@ -3779,16 +3788,11 @@ cp_tree_equal (tree t1, tree t2)
 				     CHECK_CONSTR_ARGS (t2)));
 
     case TREE_VEC:
-      {
-	unsigned ix;
-	if (TREE_VEC_LENGTH (t1) != TREE_VEC_LENGTH (t2))
-	  return false;
-	for (ix = TREE_VEC_LENGTH (t1); ix--;)
-	  if (!cp_tree_equal (TREE_VEC_ELT (t1, ix),
-			      TREE_VEC_ELT (t2, ix)))
-	    return false;
-	return true;
-      }
+      /* These are template args.  Really we should be getting the
+	 caller to do this as it knows it to be true.  */
+      if (!comp_template_args (t1, t2, NULL, NULL, false))
+	return false;
+      return true;
 
     case SIZEOF_EXPR:
     case ALIGNOF_EXPR: