Don't initialize unused cdef-function optional args

Cython/Compiler/FlowControl.py

@@ -523,7 +523,6 @@ def check_definitions(flow, compiler_directives):
             if is_arg:
                 if warn_unused_arg:
                     messages.warning(entry.pos, "Unused argument '%s'" % entry.name)
-                entry.cf_used = False
             else:
                 if warn_unused:
                     messages.warning(entry.pos, "Unused entry '%s'" % entry.name)

Cython/Compiler/Nodes.py

@@ -1828,8 +1828,11 @@ class CFuncDefNode(FuncDefNode):
         code.putln("%s%s%s {" % (storage_class, modifiers, header))
 
     def generate_argument_declarations(self, env, code):
+        scope = self.local_scope
         for arg in self.args:
             if arg.default:
+                entry = scope.lookup(arg.name)
+                if entry.cf_used:
                     result = arg.calculate_default_value_code(code)
                     code.putln('%s = %s;' % (
                         arg.type.declaration_code(arg.cname), result))
@@ -1839,17 +1842,26 @@ class CFuncDefNode(FuncDefNode):
 
     def generate_argument_parsing_code(self, env, code):
         i = 0
+        used = 0
         if self.type.optional_arg_count:
+            scope = self.local_scope
             code.putln('if (%s) {' % Naming.optional_args_cname)
             for arg in self.args:
                 if arg.default:
-                    code.putln('if (%s->%sn > %s) {' % (Naming.optional_args_cname, Naming.pyrex_prefix, i))
+                    entry = scope.lookup(arg.name)
+                    if entry.cf_used:
+                        code.putln('if (%s->%sn > %s) {' %
+                                   (Naming.optional_args_cname,
+                                    Naming.pyrex_prefix, i))
                         declarator = arg.declarator
                         while not hasattr(declarator, 'name'):
                             declarator = declarator.base
-                    code.putln('%s = %s->%s;' % (arg.cname, Naming.optional_args_cname, self.type.opt_arg_cname(declarator.name)))
+                        code.putln('%s = %s->%s;' %
+                                   (arg.cname, Naming.optional_args_cname,
+                                    self.type.opt_arg_cname(declarator.name)))
+                        used += 1
                     i += 1
-            for _ in range(self.type.optional_arg_count):
+            for _ in range(used):
                 code.putln('}')
             code.putln('}')