bpo-46031: add POP_JUMP_IF_NOT_NONE and POP_JUMP_IF_NONE (GH-30019)

Author: penguin-wwy

Doc/library/dis.rst

@@ -896,6 +896,20 @@ All of the following opcodes use their arguments.
    .. versionadded:: 3.11
 
 
+.. opcode:: POP_JUMP_IF_NOT_NONE (target)
+
+   If TOS is not none, sets the bytecode counter to *target*.  TOS is popped.
+
+   .. versionadded:: 3.11
+
+
+.. opcode:: POP_JUMP_IF_NONE (target)
+
+   If TOS is none, sets the bytecode counter to *target*.  TOS is popped.
+
+   .. versionadded:: 3.11
+
+
 .. opcode:: PREP_RERAISE_STAR
 
    Combines the raised and reraised exceptions list from TOS, into an exception

Doc/whatsnew/3.11.rst

@@ -398,6 +398,9 @@ CPython bytecode changes
 * Added :opcode:`COPY`, which pushes the *i*-th item to the top of the stack.
   The item is not removed from its original location.
 
+* Add :opcode:`POP_JUMP_IF_NOT_NONE` and :opcode:`POP_JUMP_IF_NONE` opcodes to
+  speed up conditional jumps.
+
 * :opcode:`JUMP_IF_NOT_EXC_MATCH` no longer pops the active exception.
 
 

Include/opcode.h

@@ -378,6 +378,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.11a4 3470 (bpo-46221: PREP_RERAISE_STAR no longer pushes lasti)
 #     Python 3.11a4 3471 (bpo-46202: remove pop POP_EXCEPT_AND_RERAISE)
 #     Python 3.11a4 3472 (bpo-46009: replace GEN_START with POP_TOP)
+#     Python 3.11a4 3473 (Add POP_JUMP_IF_NOT_NONE/POP_JUMP_IF_NONE opcodes)
 
 #
 # MAGIC must change whenever the bytecode emitted by the compiler may no
@@ -387,7 +388,7 @@ def _write_atomic(path, data, mode=0o666):
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3472).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3473).to_bytes(2, 'little') + b'\r\n'
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 
 _PYCACHE = '__pycache__'

Lib/importlib/_bootstrap_external.py

@@ -148,9 +148,9 @@ def jabs_op(name, op):
 haslocal.append(125)
 def_op('DELETE_FAST', 126)      # Local variable number
 haslocal.append(126)
-
 jabs_op('JUMP_IF_NOT_EG_MATCH', 127)
-
+jabs_op('POP_JUMP_IF_NOT_NONE', 128)
+jabs_op('POP_JUMP_IF_NONE', 129)
 def_op('RAISE_VARARGS', 130)    # Number of raise arguments (1, 2, or 3)
 
 def_op('MAKE_FUNCTION', 132)    # Flags

Lib/opcode.py

@@ -0,0 +1 @@
+Add :opcode:`POP_JUMP_IF_NOT_NONE` and :opcode:`POP_JUMP_IF_NONE` opcodes to speed up conditional jumps.

Misc/NEWS.d/next/Core and Builtins/2021-12-10-09-10-32.bpo-46031.rM7JOX.rst

@@ -4049,6 +4049,30 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, InterpreterFrame *frame, int thr
             DISPATCH();
         }
 
+        TARGET(POP_JUMP_IF_NOT_NONE) {
+            PyObject *value = POP();
+            if (!Py_IsNone(value)) {
+                Py_DECREF(value);
+                JUMPTO(oparg);
+                CHECK_EVAL_BREAKER();
+                DISPATCH();
+            }
+            Py_DECREF(value);
+            DISPATCH();
+        }
+
+        TARGET(POP_JUMP_IF_NONE) {
+            PyObject *value = POP();
+            if (Py_IsNone(value)) {
+                Py_DECREF(value);
+                JUMPTO(oparg);
+                CHECK_EVAL_BREAKER();
+                DISPATCH();
+            }
+            Py_DECREF(value);
+            DISPATCH();
+        }
+
         TARGET(JUMP_IF_FALSE_OR_POP) {
             PyObject *cond = TOP();
             int err;

Python/ceval.c

@@ -1110,6 +1110,8 @@ stack_effect(int opcode, int oparg, int jump)
 
         case POP_JUMP_IF_FALSE:
         case POP_JUMP_IF_TRUE:
+        case POP_JUMP_IF_NONE:
+        case POP_JUMP_IF_NOT_NONE:
             return -1;
 
         case LOAD_GLOBAL:
@@ -8519,6 +8521,21 @@ optimize_basic_block(struct compiler *c, basicblock *bb, PyObject *consts)
                             bb->b_instr[i+1].i_opcode = NOP;
                         }
                         break;
+                    case IS_OP:
+                        cnt = get_const_value(inst->i_opcode, oparg, consts);
+                        if (cnt == NULL) {
+                            goto error;
+                        }
+                        int jump_op = i+2 < bb->b_iused ? bb->b_instr[i+2].i_opcode : 0;
+                        if (Py_IsNone(cnt) && (jump_op == POP_JUMP_IF_FALSE || jump_op == POP_JUMP_IF_TRUE)) {
+                            unsigned char nextarg = bb->b_instr[i+1].i_oparg;
+                            inst->i_opcode = NOP;
+                            bb->b_instr[i+1].i_opcode = NOP;
+                            bb->b_instr[i+2].i_opcode = nextarg ^ (jump_op == POP_JUMP_IF_FALSE) ?
+                                    POP_JUMP_IF_NOT_NONE : POP_JUMP_IF_NONE;
+                        }
+                        Py_DECREF(cnt);
+                        break;
                 }
                 break;
             }
@@ -8611,6 +8628,14 @@ optimize_basic_block(struct compiler *c, basicblock *bb, PyObject *consts)
                         break;
                 }
                 break;
+            case POP_JUMP_IF_NOT_NONE:
+            case POP_JUMP_IF_NONE:
+                switch (target->i_opcode) {
+                    case JUMP_ABSOLUTE:
+                    case JUMP_FORWARD:
+                        i -= jump_thread(inst, target, inst->i_opcode);
+                }
+                break;
             case POP_JUMP_IF_FALSE:
                 switch (target->i_opcode) {
                     case JUMP_ABSOLUTE:
@@ -8766,6 +8791,8 @@ normalize_basic_block(basicblock *bb) {
             case JUMP_FORWARD:
                 bb->b_nofallthrough = 1;
                 /* fall through */
+            case POP_JUMP_IF_NOT_NONE:
+            case POP_JUMP_IF_NONE:
             case POP_JUMP_IF_FALSE:
             case POP_JUMP_IF_TRUE:
             case JUMP_IF_FALSE_OR_POP: