extend PyLong optimisation to '>>' (rshift) operator

CHANGES.rst

@@ -19,8 +19,8 @@ Features added
 
 * Adding/subtracting constant Python floats and small integers is faster.
 
-* Binary and/or/xor operations and modulus with small constant Python integers
-  are faster.
+* Binary and/or/xor/rshift operations and modulus with small constant Python
+  integers are faster.
 
 Bugs fixed
 ----------

Cython/Compiler/Optimize.py

@@ -2811,6 +2811,13 @@ class OptimizeBuiltinCalls(Visitor.NodeRefCleanupMixin,
     def _handle_simple_method_object___xor__(self, node, function, args, is_unbound_method):
         return self._optimise_num_binop('Xor', node, function, args, is_unbound_method)
 
+    def _handle_simple_method_object___rshift__(self, node, function, args, is_unbound_method):
+        if len(args) != 2 or not isinstance(args[1], ExprNodes.IntNode):
+            return node
+        if not args[1].has_constant_result() or not (1 <= args[1].constant_result <= 63):
+            return node
+        return self._optimise_num_binop('Rshift', node, function, args, is_unbound_method)
+
     def _handle_simple_method_object___mod__(self, node, function, args, is_unbound_method):
         if len(args) != 2 or not isinstance(args[1], ExprNodes.IntNode):
             return node
@@ -2826,25 +2833,26 @@ class OptimizeBuiltinCalls(Visitor.NodeRefCleanupMixin,
 
     def _optimise_num_binop(self, operator, node, function, args, is_unbound_method):
         """
-        Optimise '+' / '-' operator for (likely) float or small integer operations.
+        Optimise math operators for (likely) float or small integer operations.
         """
         if len(args) != 2:
             return node
         if not node.type.is_pyobject:
             return node
 
-        # when adding IntNode/FloatNode to something else, assume other operand is also numeric
+        # When adding IntNode/FloatNode to something else, assume other operand is also numeric.
+        # Prefer constants on RHS as they allows better size control for some operators.
         num_nodes = (ExprNodes.IntNode, ExprNodes.FloatNode)
-        if isinstance(args[0], num_nodes):
-            if args[1].type is not PyrexTypes.py_object_type:
-                return node
-            numval = args[0]
-            arg_order = 'CObj'
-        elif isinstance(args[1], num_nodes):
+        if isinstance(args[1], num_nodes):
             if args[0].type is not PyrexTypes.py_object_type:
                 return node
             numval = args[1]
             arg_order = 'ObjC'
+        elif isinstance(args[0], num_nodes):
+            if args[1].type is not PyrexTypes.py_object_type:
+                return node
+            numval = args[0]
+            arg_order = 'CObj'
         else:
             return node
 

Cython/Utility/Optimize.c

@@ -494,7 +494,7 @@ static PyObject* __Pyx_PyInt_{{op}}{{order}}(PyObject *op1, PyObject *op2, long
 
 #if CYTHON_COMPILING_IN_CPYTHON
 {{py: pyval, ival = ('op2', 'b') if order == 'CObj' else ('op1', 'a') }}
-{{py: c_op = {'Add': '+', 'Subtract': '-', 'Remainder': '%', 'Or': '|', 'Xor': '^', 'And': '&'}[op] }}
+{{py: c_op = {'Add': '+', 'Subtract': '-', 'Remainder': '%', 'Or': '|', 'Xor': '^', 'And': '&', 'Rshift': '>>'}[op] }}
 
 static PyObject* __Pyx_PyInt_{{op}}{{order}}(PyObject *op1, PyObject *op2, CYTHON_UNUSED long intval, int inplace) {
     #if PY_MAJOR_VERSION < 3

tests/run/pyintop.pyx

 # mode: run
 
 
+def bigint(x):
+    # avoid 'L' postfix in Py2.x
+    print(str(x).rstrip('L'))
+
+
 def or_obj(obj2, obj3):
     """
     >>> or_obj(2, 3)
@@ -79,6 +84,52 @@ def rshift_obj(obj2, obj3):
     return obj1
 
 
+def rshift_int(obj2):
+    """
+    >>> rshift_int(2)
+    0
+
+    >>> rshift_int(27)
+    3
+    >>> (-27) >> 3
+    -4
+    >>> rshift_int(-27)
+    -4
+
+    >>> rshift_int(32)
+    4
+    >>> (-32) >> 3
+    -4
+    >>> rshift_int(-32)
+    -4
+
+    >>> (2**28) >> 3
+    33554432
+    >>> rshift_int(2**28)
+    33554432
+    >>> (-2**28) >> 3
+    -33554432
+    >>> rshift_int(-2**28)
+    -33554432
+
+    >>> (2**30) >> 3
+    134217728
+    >>> rshift_int(2**30)
+    134217728
+    >>> rshift_int(-2**30)
+    -134217728
+
+    >>> bigint((2**60) >> 3)
+    144115188075855872
+    >>> bigint(rshift_int(2**60))
+    144115188075855872
+    >>> bigint(rshift_int(-2**60))
+    -144115188075855872
+    """
+    obj1 = obj2 >> 3
+    return obj1
+
+
 def mixed_obj(obj2, obj3):
     """
     >>> mixed_obj(2, 3)