[PATCH] Clean up old code in callback_only attribute handler

[Josef Melcr]

Hi,
this patch cleans up two useless loops from the callback_only attribute
handler.

The first loop used to check for void_list_node, now it does
literally nothing.  Seems like I forgot to remove it when I changed the
validation logic a few weeks ago.

The second loop also checks for void_list_node and decrements type_nargs
if it finds it, but since we ensure !stdarg_p for both the carrying and
the callback function, looking for void_list_node again is pointless.
In this case, we can just initialize type_nargs differently.

Bootstrapped and regtested on x86_64-linux with no new regressions.  OK
for master?

Best regards,
Josef

gcc/c-family/ChangeLog:

        * c-attribs.cc (handle_callback_only_attribute): Clean up old code.

Signed-off-by: Josef Melcr <josef.me...@suse.com>
---
 gcc/c-family/c-attribs.cc | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/gcc/c-family/c-attribs.cc b/gcc/c-family/c-attribs.cc
index 54403011063..204055f6332 100644
--- a/gcc/c-family/c-attribs.cc
+++ b/gcc/c-family/c-attribs.cc
@@ -4716,10 +4716,6 @@ handle_callback_only_attribute (tree *node, tree name, 
tree args,
      DECL_ARGUMENTS returns NULL at this point.  */
   int callback_fn_idx = TREE_INT_CST_LOW (val);
   tree decl_type_args = TYPE_ARG_TYPES (decl_type);
-  tree it;
-  for (it = decl_type_args; it != NULL_TREE; it = TREE_CHAIN (it))
-    if (it == void_list_node)
-      break;
 
   if (callback_fn_idx == CB_UNKNOWN_POS)
     {
@@ -4768,13 +4764,7 @@ handle_callback_only_attribute (tree *node, tree name, 
tree args,
   /* Compare the length of the list of argument indices
      and the real number of parameters the callback takes.  */
   unsigned cfn_nargs = list_length (TREE_CHAIN (args));
-  unsigned type_nargs = list_length (type_args);
-  for (it = type_args; it != NULL_TREE; it = TREE_CHAIN (it))
-    if (it == void_list_node)
-      {
-       --type_nargs;
-       break;
-      }
+  unsigned type_nargs = list_length (type_args) - 1;
   if (cfn_nargs != type_nargs)
     {
       warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wattributes,
@@ -4785,7 +4775,7 @@ handle_callback_only_attribute (tree *node, tree name, 
tree args,
     }
 
   unsigned curr = 0;
-  tree cfn_it;
+  tree it, cfn_it;
   /* Validate type compatibility of the arguments passed
      from caller function to callback.  "it" is used to step
      through the parameters of the caller, "cfn_it" is
-- 
2.55.0