bpo-45510: Specialize BINARY_SUBTRACT (GH-29523)

Author: corona10

Include/internal/pycore_long.h

@@ -23,6 +23,7 @@ static inline PyObject* _PyLong_GetOne(void)
 
 PyObject *_PyLong_Add(PyLongObject *left, PyLongObject *right);
 PyObject *_PyLong_Multiply(PyLongObject *left, PyLongObject *right);
+PyObject *_PyLong_Subtract(PyLongObject *left, PyLongObject *right);
 
 /* Used by Python/mystrtoul.c, _PyBytes_FromHex(),
    _PyBytes_DecodeEscape(), etc. */

Include/opcode.h

@@ -231,6 +231,8 @@ def jabs_op(name, op):
     "BINARY_OP_INPLACE_ADD_UNICODE",
     "BINARY_OP_MULTIPLY_INT",
     "BINARY_OP_MULTIPLY_FLOAT",
+    "BINARY_OP_SUBTRACT_INT",
+    "BINARY_OP_SUBTRACT_FLOAT",
     "BINARY_SUBSCR_ADAPTIVE",
     "BINARY_SUBSCR_LIST_INT",
     "BINARY_SUBSCR_TUPLE_INT",

Lib/opcode.py

@@ -3155,14 +3155,11 @@ long_add(PyLongObject *a, PyLongObject *b)
     return _PyLong_Add(a, b);
 }
 
-
-static PyObject *
-long_sub(PyLongObject *a, PyLongObject *b)
+PyObject *
+_PyLong_Subtract(PyLongObject *a, PyLongObject *b)
 {
     PyLongObject *z;
 
-    CHECK_BINOP(a, b);
-
     if (IS_MEDIUM_VALUE(a) && IS_MEDIUM_VALUE(b)) {
         return _PyLong_FromSTwoDigits(medium_value(a) - medium_value(b));
     }
@@ -3187,6 +3184,13 @@ long_sub(PyLongObject *a, PyLongObject *b)
     return (PyObject *)z;
 }
 
+static PyObject *
+long_sub(PyLongObject *a, PyLongObject *b)
+{
+    CHECK_BINOP(a, b);
+    return _PyLong_Subtract(a, b);
+}
+
 /* Grade school multiplication, ignoring the signs.
  * Returns the absolute value of the product, or NULL if error.
  */

Objects/longobject.c

@@ -2009,6 +2009,41 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, InterpreterFrame *frame, int thr
             DISPATCH();
         }
 
+        TARGET(BINARY_OP_SUBTRACT_INT) {
+            PyObject *left = SECOND();
+            PyObject *right = TOP();
+            DEOPT_IF(!PyLong_CheckExact(left), BINARY_OP);
+            DEOPT_IF(!PyLong_CheckExact(right), BINARY_OP);
+            STAT_INC(BINARY_OP, hit);
+            PyObject *sub = _PyLong_Subtract((PyLongObject *)left, (PyLongObject *)right);
+            SET_SECOND(sub);
+            Py_DECREF(right);
+            Py_DECREF(left);
+            STACK_SHRINK(1);
+            if (sub == NULL) {
+                goto error;
+            }
+            DISPATCH();
+        }
+
+        TARGET(BINARY_OP_SUBTRACT_FLOAT) {
+            PyObject *left = SECOND();
+            PyObject *right = TOP();
+            DEOPT_IF(!PyFloat_CheckExact(left), BINARY_OP);
+            DEOPT_IF(!PyFloat_CheckExact(right), BINARY_OP);
+            STAT_INC(BINARY_OP, hit);
+            double dsub = ((PyFloatObject *)left)->ob_fval - ((PyFloatObject *)right)->ob_fval;
+            PyObject *sub = PyFloat_FromDouble(dsub);
+            SET_SECOND(sub);
+            Py_DECREF(right);
+            Py_DECREF(left);
+            STACK_SHRINK(1);
+            if (sub == NULL) {
+                goto error;
+            }
+            DISPATCH();
+        }
+
         TARGET(BINARY_OP_ADD_UNICODE) {
             PyObject *left = SECOND();
             PyObject *right = TOP();

Python/ceval.c

@@ -1424,6 +1424,19 @@ _Py_Specialize_BinaryOp(PyObject *lhs, PyObject *rhs, _Py_CODEUNIT *instr,
                 goto success;
             }
             break;
+        case NB_SUBTRACT:
+        case NB_INPLACE_SUBTRACT:
+            if (PyLong_CheckExact(lhs)) {
+                *instr = _Py_MAKECODEUNIT(BINARY_OP_SUBTRACT_INT,
+                                          _Py_OPARG(*instr));
+                goto success;
+            }
+            if (PyFloat_CheckExact(lhs)) {
+                *instr = _Py_MAKECODEUNIT(BINARY_OP_SUBTRACT_FLOAT,
+                                          _Py_OPARG(*instr));
+                goto success;
+            }
+            break;
         default:
             // These operators don't have any available specializations. Rather
             // than repeatedly attempting to specialize them, just convert them