fix repeated list multiplication

--HG--
extra : amend_source : 2797e0ad678cc0a33a2548a8a20b00475bc8a21b

CHANGES.rst

@@ -11,6 +11,9 @@ Features added
 Bugs fixed
 ----------
 
+* List/Tuple literals multiplied by more than one factor were only multiplied
+  by the last factor instead of all.
+
 * In-place assignments to variables with inferred Python builtin/extension
   types could fail with type errors if the result value type was incompatible
   with the type of the previous value.

Cython/Compiler/Optimize.py

@@ -3379,18 +3379,29 @@ class ConstantFolding(Visitor.VisitorTransform, SkipDeclarations):
 
     def visit_MulNode(self, node):
         self._calculate_const(node)
-        if isinstance(node.operand1, (ExprNodes.ListNode, ExprNodes.TupleNode)):
-            return self._calculate_constant_seq(node.operand1, node.operand2)
+        if node.operand1.is_sequence_constructor:
+            return self._calculate_constant_seq(node, node.operand1, node.operand2)
         if isinstance(node.operand1, ExprNodes.IntNode) and \
-                isinstance(node.operand2, (ExprNodes.ListNode, ExprNodes.TupleNode)):
-            return self._calculate_constant_seq(node.operand2, node.operand1)
+                node.operand2.is_sequence_constructor:
+            return self._calculate_constant_seq(node, node.operand2, node.operand1)
         return self.visit_BinopNode(node)
 
-    def _calculate_constant_seq(self, sequence_node, factor):
+    def _calculate_constant_seq(self, node, sequence_node, factor):
         if factor.constant_result != 1 and sequence_node.args:
             if isinstance(factor.constant_result, (int, long)) and factor.constant_result <= 0:
                 del sequence_node.args[:]
-                factor = None
+                sequence_node.mult_factor = None
+            elif sequence_node.mult_factor is not None:
+                if (isinstance(factor.constant_result, (int, long)) and
+                        isinstance(sequence_node.mult_factor.constant_result, (int, long))):
+                    value = sequence_node.mult_factor.constant_result * factor.constant_result
+                    sequence_node.mult_factor = ExprNodes.IntNode(
+                        sequence_node.mult_factor.pos,
+                        value=str(value), constant_result=value)
+                else:
+                    # don't know if we can combine the factors, so don't
+                    return self.visit_BinopNode(node)
+            else:
                 sequence_node.mult_factor = factor
         return sequence_node
 

tests/run/constant_folding.py

@@ -291,6 +291,28 @@ def mult_empty_list():
     return 5 * [] * 100
 
 
+@cython.test_fail_if_path_exists(
+    "//MulNode",
+)
+def mult_list_int_int():
+    """
+    >>> mult_list_int_int()
+    [1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2]
+    """
+    return [1, 2] * 2 * 3
+
+
+@cython.test_fail_if_path_exists(
+    "//MulNode",
+)
+def mult_int_list_int():
+    """
+    >>> mult_int_list_int()
+    [1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2]
+    """
+    return 3 * [1, 2] * 2
+
+
 @cython.test_fail_if_path_exists(
     "//MulNode",
     "//ListNode//IntNode",