GH-100982: Break up COMPARE_AND_BRANCH (GH-102801)

Author: brandtbucher

Doc/library/dis.rst

@@ -1042,15 +1042,6 @@ iterations of the loop.
    ``cmp_op[opname]``.
 
 
-.. opcode:: COMPARE_AND_BRANCH (opname)
-
-   Compares the top two values on the stack, popping them, then branches.
-   The direction and offset of the jump is embedded as a ``POP_JUMP_IF_TRUE``
-   or ``POP_JUMP_IF_FALSE`` instruction immediately following the cache.
-
-   .. versionadded:: 3.12
-
-
 .. opcode:: IS_OP (invert)
 
    Performs ``is`` comparison, or ``is not`` if ``invert`` is 1.

Include/internal/pycore_code.h

@@ -234,7 +234,7 @@ extern void _Py_Specialize_Call(PyObject *callable, _Py_CODEUNIT *instr,
                                 int nargs, PyObject *kwnames);
 extern void _Py_Specialize_BinaryOp(PyObject *lhs, PyObject *rhs, _Py_CODEUNIT *instr,
                                     int oparg, PyObject **locals);
-extern void _Py_Specialize_CompareAndBranch(PyObject *lhs, PyObject *rhs,
+extern void _Py_Specialize_CompareOp(PyObject *lhs, PyObject *rhs,
                                      _Py_CODEUNIT *instr, int oparg);
 extern void _Py_Specialize_UnpackSequence(PyObject *seq, _Py_CODEUNIT *instr,
                                           int oparg);

Include/internal/pycore_opcode.h

@@ -435,7 +435,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.12a6 3519 (Modify SEND instruction)
 #     Python 3.12a6 3520 (Remove PREP_RERAISE_STAR, add CALL_INTRINSIC_2)
 #     Python 3.12a7 3521 (Shrink the LOAD_GLOBAL caches)
-#     Python 3.12a7 3522 (Removed JUMP_IF_FALSE_OR_POP/JUMP_IF_TRUE_OR_POP)
+#     Python 3.12a7 3523 (Convert COMPARE_AND_BRANCH back to COMPARE_OP)
 
 #     Python 3.13 will start with 3550
 
@@ -452,7 +452,7 @@ 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 = (3522).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3523).to_bytes(2, 'little') + b'\r\n'
 
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 

Include/opcode.h

@@ -191,8 +191,6 @@ def pseudo_op(name, op, real_ops):
 def_op('DELETE_DEREF', 139)
 hasfree.append(139)
 jrel_op('JUMP_BACKWARD', 140)    # Number of words to skip (backwards)
-def_op('COMPARE_AND_BRANCH', 141)   # Comparison and jump
-hascompare.append(141)
 
 def_op('CALL_FUNCTION_EX', 142)  # Flags
 
@@ -314,10 +312,10 @@ def pseudo_op(name, op, real_ops):
         "CALL_NO_KW_TUPLE_1",
         "CALL_NO_KW_TYPE_1",
     ],
-    "COMPARE_AND_BRANCH": [
-        "COMPARE_AND_BRANCH_FLOAT",
-        "COMPARE_AND_BRANCH_INT",
-        "COMPARE_AND_BRANCH_STR",
+    "COMPARE_OP": [
+        "COMPARE_OP_FLOAT",
+        "COMPARE_OP_INT",
+        "COMPARE_OP_STR",
     ],
     "FOR_ITER": [
         "FOR_ITER_LIST",
@@ -392,9 +390,6 @@ def pseudo_op(name, op, real_ops):
     "COMPARE_OP": {
         "counter": 1,
     },
-    "COMPARE_AND_BRANCH": {
-        "counter": 1,
-    },
     "BINARY_SUBSCR": {
         "counter": 1,
         "type_version": 2,

Lib/importlib/_bootstrap_external.py

@@ -1283,7 +1283,7 @@ def test_multiline_boolean_expression(self):
         self.assertOpcodeSourcePositionIs(compiled_code, 'POP_JUMP_IF_FALSE',
             line=2, end_line=2, column=15, end_column=16, occurrence=2)
         # compare d and 0
-        self.assertOpcodeSourcePositionIs(compiled_code, 'COMPARE_AND_BRANCH',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'COMPARE_OP',
             line=4, end_line=4, column=8, end_column=13, occurrence=1)
         # jump if comparison it True
         self.assertOpcodeSourcePositionIs(compiled_code, 'POP_JUMP_IF_TRUE',

Lib/opcode.py

@@ -46,7 +46,7 @@ def cm(cls, x):
 
 %3d        LOAD_FAST                1 (x)
            LOAD_CONST               1 (1)
-           COMPARE_OP              32 (==)
+           COMPARE_OP              40 (==)
            LOAD_FAST                0 (self)
            STORE_ATTR               0 (x)
            RETURN_CONST             0 (None)
@@ -56,7 +56,7 @@ def cm(cls, x):
        RESUME                   0
        LOAD_FAST                1
        LOAD_CONST               1
-       COMPARE_OP              32 (==)
+       COMPARE_OP              40 (==)
        LOAD_FAST                0
        STORE_ATTR               0
        RETURN_CONST             0
@@ -67,7 +67,7 @@ def cm(cls, x):
 
 %3d        LOAD_FAST                1 (x)
            LOAD_CONST               1 (1)
-           COMPARE_OP              32 (==)
+           COMPARE_OP              40 (==)
            LOAD_FAST                0 (cls)
            STORE_ATTR               0 (x)
            RETURN_CONST             0 (None)
@@ -78,7 +78,7 @@ def cm(cls, x):
 
 %3d        LOAD_FAST                0 (x)
            LOAD_CONST               1 (1)
-           COMPARE_OP              32 (==)
+           COMPARE_OP              40 (==)
            STORE_FAST               0 (x)
            RETURN_CONST             0 (None)
 """ % (_C.sm.__code__.co_firstlineno, _C.sm.__code__.co_firstlineno + 2,)
@@ -1554,12 +1554,12 @@ def _prepare_test_cases():
   Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=54, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='LOAD_FAST', opcode=124, arg=0, argval='i', argrepr='i', offset=56, starts_line=5, is_jump_target=False, positions=None),
   Instruction(opname='LOAD_CONST', opcode=100, arg=2, argval=4, argrepr='4', offset=58, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='COMPARE_AND_BRANCH', opcode=141, arg=13, argval='<', argrepr='<', offset=60, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='COMPARE_OP', opcode=107, arg=2, argval='<', argrepr='<', offset=60, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_JUMP_IF_FALSE', opcode=114, arg=1, argval=68, argrepr='to 68', offset=64, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='JUMP_BACKWARD', opcode=140, arg=21, argval=26, argrepr='to 26', offset=66, starts_line=6, is_jump_target=False, positions=None),
   Instruction(opname='LOAD_FAST', opcode=124, arg=0, argval='i', argrepr='i', offset=68, starts_line=7, is_jump_target=True, positions=None),
   Instruction(opname='LOAD_CONST', opcode=100, arg=3, argval=6, argrepr='6', offset=70, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='COMPARE_AND_BRANCH', opcode=141, arg=68, argval='>', argrepr='>', offset=72, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='COMPARE_OP', opcode=107, arg=68, argval='>', argrepr='>', offset=72, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_JUMP_IF_TRUE', opcode=115, arg=1, argval=80, argrepr='to 80', offset=76, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='JUMP_BACKWARD', opcode=140, arg=27, argval=26, argrepr='to 26', offset=78, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=80, starts_line=8, is_jump_target=True, positions=None),
@@ -1581,12 +1581,12 @@ def _prepare_test_cases():
   Instruction(opname='STORE_FAST', opcode=125, arg=0, argval='i', argrepr='i', offset=146, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='LOAD_FAST', opcode=124, arg=0, argval='i', argrepr='i', offset=148, starts_line=14, is_jump_target=False, positions=None),
   Instruction(opname='LOAD_CONST', opcode=100, arg=3, argval=6, argrepr='6', offset=150, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='COMPARE_AND_BRANCH', opcode=141, arg=75, argval='>', argrepr='>', offset=152, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='COMPARE_OP', opcode=107, arg=68, argval='>', argrepr='>', offset=152, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_JUMP_IF_FALSE', opcode=114, arg=1, argval=160, argrepr='to 160', offset=156, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='JUMP_BACKWARD', opcode=140, arg=25, argval=110, argrepr='to 110', offset=158, starts_line=15, is_jump_target=False, positions=None),
   Instruction(opname='LOAD_FAST', opcode=124, arg=0, argval='i', argrepr='i', offset=160, starts_line=16, is_jump_target=True, positions=None),
   Instruction(opname='LOAD_CONST', opcode=100, arg=2, argval=4, argrepr='4', offset=162, starts_line=None, is_jump_target=False, positions=None),
-  Instruction(opname='COMPARE_AND_BRANCH', opcode=141, arg=13, argval='<', argrepr='<', offset=164, starts_line=None, is_jump_target=False, positions=None),
+  Instruction(opname='COMPARE_OP', opcode=107, arg=2, argval='<', argrepr='<', offset=164, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='POP_JUMP_IF_FALSE', opcode=114, arg=1, argval=172, argrepr='to 172', offset=168, starts_line=None, is_jump_target=False, positions=None),
   Instruction(opname='JUMP_FORWARD', opcode=110, arg=15, argval=202, argrepr='to 202', offset=170, starts_line=17, is_jump_target=False, positions=None),
   Instruction(opname='LOAD_FAST', opcode=124, arg=0, argval='i', argrepr='i', offset=172, starts_line=11, is_jump_target=True, positions=None),

Lib/test/test_compile.py

@@ -0,0 +1 @@
+Replace all occurrences of ``COMPARE_AND_BRANCH`` with :opcode:`COMPARE_OP`.

Lib/test/test_dis.py

@@ -347,14 +347,6 @@ mark_stacks(PyCodeObject *code_obj, int len)
                     assert(stacks[j] == UNINITIALIZED || stacks[j] == next_stack);
                     stacks[j] = next_stack;
                     break;
-                case COMPARE_AND_BRANCH:
-                    next_stack = pop_value(pop_value(next_stack));
-                    i++;
-                    j = get_arg(code, i) + i + 1;
-                    assert(j < len);
-                    assert(stacks[j] == UNINITIALIZED || stacks[j] == next_stack);
-                    stacks[j] = next_stack;
-                    break;
                 case GET_ITER:
                 case GET_AITER:
                     next_stack = push_value(pop_value(next_stack), Iterator);