Add test code

Author: corona10

Lib/test/test_peepholer.py

@@ -1083,5 +1083,52 @@ def test_no_unsafe_static_swap(self):
         ]
         self.cfg_optimization_test(insts, expected_insts, consts=list(range(3)), nlocals=1)
 
+    def test_dead_store_elimination_in_same_lineno(self):
+        insts = [
+            ('LOAD_CONST', 0, 1),
+            ('LOAD_CONST', 1, 2),
+            ('LOAD_CONST', 2, 3),
+            ('SWAP', 3, 4),
+            ('STORE_FAST', 1, 4),
+            ('STORE_FAST', 1, 4),
+            ('STORE_FAST', 1, 4),
+            ('RETURN_VALUE', 5)
+        ]
+        expected_insts = [
+            ('LOAD_CONST', 0, 1),
+            ('LOAD_CONST', 1, 2),
+            ('LOAD_CONST', 2, 3),
+            ('SWAP', 3, 4),
+            ('POP_TOP', 0, 4),
+            ('POP_TOP', 0, 4),
+            ('STORE_FAST', 1, 4),
+            ('RETURN_VALUE', 5)
+        ]
+        self.cfg_optimization_test(insts, expected_insts, consts=list(range(3)), nlocals=1)
+
+    def test_no_dead_store_elimination_in_different_lineno(self):
+        insts = [
+            ('LOAD_CONST', 0, 1),
+            ('LOAD_CONST', 1, 2),
+            ('LOAD_CONST', 2, 3),
+            ('SWAP', 3, 4),
+            ('STORE_FAST', 1, 4),
+            ('STORE_FAST', 1, 5),
+            ('STORE_FAST', 1, 6),
+            ('RETURN_VALUE', 5)
+        ]
+        expected_insts = [
+            ('LOAD_CONST', 0, 1),
+            ('LOAD_CONST', 1, 2),
+            ('LOAD_CONST', 2, 3),
+            ('SWAP', 3, 4),
+            ('STORE_FAST', 1, 4),
+            ('STORE_FAST', 1, 5),
+            ('STORE_FAST', 1, 6),
+            ('RETURN_VALUE', 5)
+        ]
+        self.cfg_optimization_test(insts, expected_insts, consts=list(range(3)), nlocals=1)
+
+
 if __name__ == "__main__":
     unittest.main()