Mark some Integer methods as inline (#3264)

Merged-By: k0kubun <takashikkbn@gmail.com>

integer.rb

@@ -1,4 +1,82 @@
 class Integer
+  def abs
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'rb_int_abs(self)'
+  end
+
+  def bit_length
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'rb_int_bit_length(self)'
+  end
+
+  #  call-seq:
+  #     int.even?  ->  true or false
+  #
+  #  Returns +true+ if +int+ is an even number.
+  def even?
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'int_even_p(self)'
+  end
+
+  #  call-seq:
+  #     int.integer?  ->  true
+  #
+  #  Since +int+ is already an Integer, this always returns +true+.
+  def integer?
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'Qtrue'
+  end
+
+  def magnitude
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'rb_int_abs(self)'
+  end
+
+  #  call-seq:
+  #     int.odd?  ->  true or false
+  #
+  #  Returns +true+ if +int+ is an odd number.
+  def odd?
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'rb_int_odd_p(self)'
+  end
+
+  #  call-seq:
+  #     int.ord  ->  self
+  #
+  #  Returns the +int+ itself.
+  #
+  #     97.ord   #=> 97
+  #
+  #  This method is intended for compatibility to character literals
+  #  in Ruby 1.9.
+  #
+  #  For example, <code>?a.ord</code> returns 97 both in 1.8 and 1.9.
+  def ord
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'self'
+  end
+
+  #  call-seq:
+  #     int.to_i    ->  integer
+  #
+  #  Since +int+ is already an Integer, returns +self+.
+  #
+  #  #to_int is an alias for #to_i.
+  def to_i
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'self'
+  end
+
+  #  call-seq:
+  #     int.to_int  ->  integer
+  #
+  #  Since +int+ is already an Integer, returns +self+.
+  def to_int
+    Primitive.attr! 'inline'
+    Primitive.cexpr! 'self'
+  end
+
   # call-seq:
   #    int.zero? -> true or false
   #