Optimize compare_op_str and add test

Author: savannahostrowski

Lib/test/test_capi/test_opt.py

@@ -843,7 +843,6 @@ def testfunc(n):
         self.assertLessEqual(len(guard_tos_unicode_count), 1)
         self.assertLessEqual(len(guard_nos_unicode_count), 1)
         self.assertIn("_COMPARE_OP_STR", uops)
-        self.assertNotIn("_POP_TWO_LOAD_CONST_INLINE_BORROW", uops)
 
     def test_type_inconsistency(self):
         ns = {}
@@ -1615,7 +1614,7 @@ def f(n):
         # But all of the appends we care about are still there:
         self.assertEqual(uops.count("_CALL_LIST_APPEND"), len("ABCDEFG"))
 
-    def test_compare_pop_two_load_const_inline_borrow(self):
+    def test_compare_op_int_pop_two_load_const_inline_borrow(self):
         def testfunc(n):
             x = 0
             for _ in range(n):
@@ -1632,6 +1631,23 @@ def testfunc(n):
         self.assertNotIn("_COMPARE_OP_INT", uops)
         self.assertNotIn("_POP_TWO_LOAD_CONST_INLINE_BORROW", uops)
 
+    def test_compare_op_str_pop_two_load_const_inline_borrow(self):
+        def testfunc(n):
+            x = 0
+            for _ in range(n):
+                a = "foo"
+                b = "foo"
+                if a == b:
+                    x += 1
+            return x
+
+        res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
+        self.assertEqual(res, TIER2_THRESHOLD)
+        self.assertIsNotNone(ex)
+        uops = get_opnames(ex)
+        self.assertNotIn("_COMPARE_OP_STR", uops)
+        self.assertNotIn("_POP_TWO_LOAD_CONST_INLINE_BORROW", uops)
+
     def test_to_bool_bool_contains_op_set(self):
         """
         Test that _TO_BOOL_BOOL is removed from code like:

Python/optimizer_bytecodes.c

@@ -440,7 +440,7 @@ dummy_func(void) {
     }
 
     op(_COMPARE_OP_STR, (left, right -- res)) {
-        // REPLACE_OPCODE_IF_EVALUATES_PURE(left, right);
+        REPLACE_OPCODE_IF_EVALUATES_PURE(left, right);
         res = sym_new_type(ctx, &PyBool_Type);
     }