Add COMPARE_IS_NONE opcode to CPython for performance

is_none_bytecode.diff

b66bbc41ce52efe667af0ba47a6098216b758236
diff --git a/Include/opcode.h b/Include/opcode.h
index 99c3b0ef81..dceedc662a 100644
--- a/Include/opcode.h
+++ b/Include/opcode.h
@@ -12,6 +12,8 @@ extern "C" {
 #define ROT_THREE                 3
 #define DUP_TOP                   4
 #define DUP_TOP_TWO               5
+#define COMPARE_IS_NONE           6
+#define COMPARE_IS_NOT_NONE       7
 #define NOP                       9
 #define UNARY_POSITIVE           10
 #define UNARY_NEGATIVE           11
diff --git a/Lib/opcode.py b/Lib/opcode.py
index dffb38c314..53fac107c1 100644
--- a/Lib/opcode.py
+++ b/Lib/opcode.py
@@ -60,6 +60,8 @@ def_op('ROT_TWO', 2)
 def_op('ROT_THREE', 3)
 def_op('DUP_TOP', 4)
 def_op('DUP_TOP_TWO', 5)
+def_op('COMPARE_IS_NONE', 6)
+def_op('COMPARE_IS_NOT_NONE', 7)
 
 def_op('NOP', 9)
 def_op('UNARY_POSITIVE', 10)
diff --git a/Python/ceval.c b/Python/ceval.c
index 3243a4f8a0..40d697c193 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1235,6 +1235,28 @@ _PyEval_EvalFrameDefault(PyFrameObject *f, int throwflag)
             FAST_DISPATCH();
         }
 
+        TARGET(COMPARE_IS_NONE) {
+            PyObject *top = TOP();
+            PyObject *res = (top == Py_None) ? Py_True : Py_False;
+            Py_INCREF(res);
+            Py_DECREF(top);
+            SET_TOP(res);
+            PREDICT(POP_JUMP_IF_FALSE);
+            PREDICT(POP_JUMP_IF_TRUE);
+            DISPATCH();
+        }
+
+        TARGET(COMPARE_IS_NOT_NONE) {
+            PyObject *top = TOP();
+            PyObject *res = (top != Py_None) ? Py_True : Py_False;
+            Py_INCREF(res);
+            Py_DECREF(top);
+            SET_TOP(res);
+            PREDICT(POP_JUMP_IF_FALSE);
+            PREDICT(POP_JUMP_IF_TRUE);
+            DISPATCH();
+        }
+
         TARGET(UNARY_POSITIVE) {
             PyObject *value = TOP();
             PyObject *res = PyNumber_Positive(value);
diff --git a/Python/compile.c b/Python/compile.c
index 280ddc39e3..8fc39d092e 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -867,6 +867,10 @@ PyCompile_OpcodeStackEffect(int opcode, int oparg)
         case DUP_TOP_TWO:
             return 2;
 
+        case COMPARE_IS_NONE:
+        case COMPARE_IS_NOT_NONE:
+            return 0;
+
         case UNARY_POSITIVE:
         case UNARY_NEGATIVE:
         case UNARY_NOT:
@@ -3419,6 +3423,24 @@ compiler_compare(struct compiler *c, expr_ty e)
     VISIT(c, expr, e->v.Compare.left);
     n = asdl_seq_LEN(e->v.Compare.ops);
     assert(n > 0);
+
+    if (n == 1) {
+        cmpop_ty cmp = (cmpop_ty)asdl_seq_GET(e->v.Compare.ops, 0);
+        expr_ty exp = (expr_ty)asdl_seq_GET(e->v.Compare.comparators, 0);
+        if (exp->kind == NameConstant_kind && exp->v.NameConstant.value == Py_None) {
+            if (cmp == Is) {
+                ADDOP(c, COMPARE_IS_NONE);
+                return 1;
+            } else if (cmp == IsNot) {
+                ADDOP(c, COMPARE_IS_NOT_NONE);
+                return 1;
+            }
+        }
+        VISIT(c, expr, exp);
+        ADDOP_I(c, COMPARE_OP, cmpop(cmp));
+        return 1;
+    }
+
     if (n > 1) {
         cleanup = compiler_new_block(c);
         if (cleanup == NULL)
diff --git a/Python/opcode_targets.h b/Python/opcode_targets.h
index 567f8723a6..d2156ca154 100644
--- a/Python/opcode_targets.h
+++ b/Python/opcode_targets.h
@@ -5,8 +5,8 @@ static void *opcode_targets[256] = {
     &&TARGET_ROT_THREE,
     &&TARGET_DUP_TOP,
     &&TARGET_DUP_TOP_TWO,
-    &&_unknown_opcode,
-    &&_unknown_opcode,
+    &&TARGET_COMPARE_IS_NONE,
+    &&TARGET_COMPARE_IS_NOT_NONE,
     &&_unknown_opcode,
     &&TARGET_NOP,
     &&TARGET_UNARY_POSITIVE,