From 4b17476f473bb73a793c9701f364b15999ca2ebd Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Thu, 5 Jan 2023 15:27:23 -0800
Subject: [PATCH 01/30] Tweak 'This file is generated...' header

---
 Tools/cases_generator/generate_cases.py | 30 +++++++++++++------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 7452b2ced05254..1d9283b3104a9d 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -15,14 +15,14 @@
 import parser
 from parser import StackEffect
 
-DEFAULT_INPUT = os.path.relpath(
-    os.path.join(os.path.dirname(__file__), "../../Python/bytecodes.c")
-)
-DEFAULT_OUTPUT = os.path.relpath(
-    os.path.join(os.path.dirname(__file__), "../../Python/generated_cases.c.h")
-)
+HERE = os.path.dirname(__file__)
+ROOT = os.path.join(HERE, "../..")
+THIS = os.path.relpath(__file__, ROOT)
+
+DEFAULT_INPUT = os.path.relpath(os.path.join(ROOT, "Python/bytecodes.c"))
+DEFAULT_OUTPUT = os.path.relpath(os.path.join(ROOT, "Python/generated_cases.c.h"))
 DEFAULT_METADATA_OUTPUT = os.path.relpath(
-    os.path.join(os.path.dirname(__file__), "../../Python/opcode_metadata.h")
+    os.path.join(ROOT, "Python/opcode_metadata.h")
 )
 BEGIN_MARKER = "// BEGIN BYTECODES //"
 END_MARKER = "// END BYTECODES //"
@@ -624,10 +624,8 @@ def write_metadata(self) -> None:
         """Write instruction metadata to output file."""
         with open(self.output_filename, "w") as f:
             # Write provenance header
-            f.write(
-                f"// This file is generated by {os.path.relpath(__file__)} --metadata\n"
-            )
-            f.write(f"// from {os.path.relpath(self.filename)}\n")
+            f.write(f"// This file is generated by {THIS} --metadata\n")
+            f.write(f"// from {os.path.relpath(self.filename, ROOT)}\n")
             f.write(f"// Do not edit!\n")
 
             # Create formatter; the rest of the code uses this
@@ -662,8 +660,11 @@ def write_metadata(self) -> None:
             # Write end of array
             self.out.emit("};")
 
-    def get_format(self, thing: Instruction | SuperInstruction | MacroInstruction) -> str:
+    def get_format(
+        self, thing: Instruction | SuperInstruction | MacroInstruction
+    ) -> str:
         """Get the format string for a single instruction."""
+
         def instr_format(instr: Instruction) -> str:
             if instr.register:
                 fmt = "IBBB"
@@ -675,6 +676,7 @@ def instr_format(instr: Instruction) -> str:
                     fmt += cache
                     cache = "0"
             return fmt
+
         match thing:
             case Instruction():
                 format = instr_format(thing)
@@ -747,8 +749,8 @@ def write_instructions(self) -> None:
         """Write instructions to output file."""
         with open(self.output_filename, "w") as f:
             # Write provenance header
-            f.write(f"// This file is generated by {os.path.relpath(__file__)}\n")
-            f.write(f"// from {os.path.relpath(self.filename)}\n")
+            f.write(f"// This file is generated by {THIS}\n")
+            f.write(f"// from {os.path.relpath(self.filename, ROOT)}\n")
             f.write(f"// Do not edit!\n")
 
             # Create formatter; the rest of the code uses this

From 69f04e4572829134adc38d099a6d80ac22107d04 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Thu, 5 Jan 2023 16:44:22 -0800
Subject: [PATCH 02/30] Start on array stack effects

---
 Tools/cases_generator/generate_cases.py | 46 ++++++++++++++++++++-----
 Tools/cases_generator/parser.py         | 33 +++++++++++++++---
 Tools/cases_generator/test_generator.py | 33 ++++++++++++++++++
 3 files changed, 99 insertions(+), 13 deletions(-)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 1d9283b3104a9d..8eb64fb4e6df0c 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -83,21 +83,28 @@ def block(self, head: str):
             yield
         self.emit("}")
 
-    def stack_adjust(self, diff: int):
+    def stack_adjust(self, diff: int, symbolic: list[str]):
         if diff > 0:
             self.emit(f"STACK_GROW({diff});")
         elif diff < 0:
             self.emit(f"STACK_SHRINK({-diff});")
+        if symbolic:
+            for sym in symbolic:
+                if sym.startswith("-"):
+                    self.emit(f"STACK_SHRINK({sym[1:]});")
+                else:
+                    self.emit(f"STACK_GROW({sym});")
 
     def declare(self, dst: StackEffect, src: StackEffect | None):
         if dst.name == UNUSED:
             return
-        typ = f"{dst.type} " if dst.type else "PyObject *"
+        typ = f"{dst.type}" if dst.type else "PyObject *"
         init = ""
         if src:
             cast = self.cast(dst, src)
             init = f" = {cast}{src.name}"
-        self.emit(f"{typ}{dst.name}{init};")
+        sepa = "" if typ.endswith("*") else " "
+        self.emit(f"{typ}{sepa}{dst.name}{init};")
 
     def assign(self, dst: StackEffect, src: StackEffect):
         if src.name == UNUSED:
@@ -105,6 +112,12 @@ def assign(self, dst: StackEffect, src: StackEffect):
         cast = self.cast(dst, src)
         if m := re.match(r"^PEEK\((\d+)\)$", dst.name):
             self.emit(f"POKE({m.group(1)}, {cast}{src.name});")
+        elif m := re.match(r"^&PEEK\(.*\)$", dst.name):
+            # NOTE: MOVE_ITEMS() does not exist.
+            # The only supported output array forms are:
+            # - unused[...]
+            # - X[...] where X[...] matches an input array form
+            self.emit(f"MOVE_ITEMS({src.name}, {dst.name}, {src.size});")
         elif m := re.match(r"^REG\(oparg(\d+)\)$", dst.name):
             self.emit(f"Py_XSETREF({dst.name}, {cast}{src.name});")
         else:
@@ -195,7 +208,10 @@ def write(self, out: Formatter) -> None:
         if not self.register:
             # Write input stack effect variable declarations and initializations
             for i, ieffect in enumerate(reversed(self.input_effects), 1):
-                src = StackEffect(f"PEEK({i})", "")
+                if ieffect.size:
+                    src = StackEffect(f"&PEEK({ieffect.size})", "PyObject **")
+                else:
+                    src = StackEffect(f"PEEK({i})", "")
                 out.declare(ieffect, src)
         else:
             # Write input register variable declarations and initializations
@@ -219,13 +235,27 @@ def write(self, out: Formatter) -> None:
 
         if not self.register:
             # Write net stack growth/shrinkage
-            diff = len(self.output_effects) - len(self.input_effects)
-            out.stack_adjust(diff)
+            diff = 0
+            symbolic: list[str] = []
+            for ieff in self.input_effects:
+                if ieff.size:
+                    symbolic.append(f"-{ieff.size}")
+                else:
+                    diff -= 1
+            for oeff in self.output_effects:
+                if oeff.size:
+                    symbolic.append(oeff.size)
+                else:
+                    diff += 1
+            out.stack_adjust(diff, symbolic)
 
             # Write output stack effect assignments
             for i, oeffect in enumerate(reversed(self.output_effects), 1):
                 if oeffect.name not in self.unmoved_names:
-                    dst = StackEffect(f"PEEK({i})", "")
+                    if oeffect.size:
+                        dst = StackEffect(f"&PEEK({oeffect.size})", "PyObject **")
+                    else:
+                        dst = StackEffect(f"PEEK({i})", "")
                     out.assign(dst, oeffect)
         else:
             # Write output register assignments
@@ -843,7 +873,7 @@ def wrap_super_or_macro(self, up: SuperOrMacroInstruction):
 
             yield
 
-            self.out.stack_adjust(up.final_sp - up.initial_sp)
+            self.out.stack_adjust(up.final_sp - up.initial_sp, [])
             for i, var in enumerate(reversed(up.stack[: up.final_sp]), 1):
                 dst = StackEffect(f"PEEK({i})", "")
                 self.out.assign(dst, var)
diff --git a/Tools/cases_generator/parser.py b/Tools/cases_generator/parser.py
index 4885394bf6b1e5..3b086413e46bff 100644
--- a/Tools/cases_generator/parser.py
+++ b/Tools/cases_generator/parser.py
@@ -62,8 +62,17 @@ class Block(Node):
 @dataclass
 class StackEffect(Node):
     name: str
-    type: str = ""
-    # TODO: array, condition
+    type: str = ""  # Optional `:type`
+    size: str = ""  # Optional `[size]`
+    # Note: we can have type or size but not both
+    # TODO: condition (can be combined with type but not size)
+
+
+@dataclass
+class Dimension(Node):
+    # NAME ['*' NUMBER]
+    name: str
+    size: int = 1
 
 
 @dataclass
@@ -224,10 +233,24 @@ def stack_effect(self) -> StackEffect | None:
         # IDENTIFIER [':' IDENTIFIER]
         # TODO: Arrays, conditions
         if tkn := self.expect(lx.IDENTIFIER):
-            type = ""
             if self.expect(lx.COLON):
-                type = self.require(lx.IDENTIFIER).text
-            return StackEffect(tkn.text, type)
+                typ = self.require(lx.IDENTIFIER)
+                return StackEffect(tkn.text, typ.text)
+            elif self.expect(lx.LBRACKET):
+                if not (dim := self.dimension()):
+                    raise self.make_syntax_error("Expected dimension")
+                self.require(lx.RBRACKET)
+                return StackEffect(tkn.text, "PyObject **", dim.text.strip())
+            else:
+                return StackEffect(tkn.text)
+
+    @contextual
+    def dimension(self) -> Dimension | None:
+        if name := self.expect(lx.IDENTIFIER):
+            if self.expect(lx.TIMES):
+                if size := self.expect(lx.NUMBER):
+                    return Dimension(name.text, int(size.text))
+            return Dimension(name.text)
 
     @contextual
     def super_def(self) -> Super | None:
diff --git a/Tools/cases_generator/test_generator.py b/Tools/cases_generator/test_generator.py
index e707a533426814..e7cc18c5f3cfe6 100644
--- a/Tools/cases_generator/test_generator.py
+++ b/Tools/cases_generator/test_generator.py
@@ -308,3 +308,36 @@ def test_macro_instruction():
         }
     """
     run_cases_test(input, output)
+
+def test_array_input():
+    input = """
+        inst(OP, (values[oparg] --)) {
+            spam();
+        }
+    """
+    output = """
+        TARGET(OP) {
+            PyObject **values = &PEEK(oparg);
+            spam();
+            STACK_SHRINK(oparg);
+            DISPATCH();
+        }
+    """
+    run_cases_test(input, output)
+
+def test_array_output():
+    input = """
+        inst(OP, (-- values[oparg])) {
+            spam();
+        }
+    """
+    output = """
+        TARGET(OP) {
+            PyObject **values;
+            spam();
+            STACK_GROW(oparg);
+            MOVE_ITEMS(values, &PEEK(oparg), oparg);
+            DISPATCH();
+        }
+    """
+    run_cases_test(input, output)

From b9bd7e39ac655f29e7d185f519bc781d0f2c1256 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Fri, 6 Jan 2023 21:00:01 -0800
Subject: [PATCH 03/30] Simple input array effects work

---
 Python/bytecodes.c                      | 13 ++++---------
 Python/compile.c                        |  2 +-
 Python/generated_cases.c.h              | 13 +++++++------
 Python/opcode_metadata.h                |  2 +-
 Tools/cases_generator/generate_cases.py | 18 ++++++++++--------
 Tools/cases_generator/test_generator.py | 12 ++++++------
 6 files changed, 29 insertions(+), 31 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 251ee564eb7275..f86649f64870b6 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1300,18 +1300,13 @@ dummy_func(
             }
         }
 
-        // stack effect: (__array[oparg] -- __0)
-        inst(BUILD_STRING) {
-            PyObject *str;
-            str = _PyUnicode_JoinArray(&_Py_STR(empty),
-                                       stack_pointer - oparg, oparg);
+        inst(BUILD_STRING, (pieces[oparg] -- str)) {
+            str = _PyUnicode_JoinArray(&_Py_STR(empty), pieces, oparg);
             if (str == NULL)
                 goto error;
-            while (--oparg >= 0) {
-                PyObject *item = POP();
-                Py_DECREF(item);
+            for (int i = 0; i < oparg; i++) {
+                Py_DECREF(pieces[i]);
             }
-            PUSH(str);
         }
 
         // stack effect: (__array[oparg] -- __0)
diff --git a/Python/compile.c b/Python/compile.c
index 62f889eb35a557..6d176a83a87acc 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -8873,7 +8873,7 @@ assemble(struct compiler *c, int addNone)
     }
 
     assert(no_redundant_jumps(g));
-    assert(opcode_metadata_is_sane(g));
+    // assert(opcode_metadata_is_sane(g));
 
     /* Can't modify the bytecode after computing jump offsets. */
     assemble_jump_offsets(g->g_entryblock);
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 218bc624fa1538..818bc68ad45086 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1511,16 +1511,17 @@
         }
 
         TARGET(BUILD_STRING) {
+            PyObject **pieces = &PEEK(oparg);
             PyObject *str;
-            str = _PyUnicode_JoinArray(&_Py_STR(empty),
-                                       stack_pointer - oparg, oparg);
+            str = _PyUnicode_JoinArray(&_Py_STR(empty), pieces, oparg);
             if (str == NULL)
                 goto error;
-            while (--oparg >= 0) {
-                PyObject *item = POP();
-                Py_DECREF(item);
+            for (int i = 0; i < oparg; i++) {
+                Py_DECREF(pieces[i]);
             }
-            PUSH(str);
+            STACK_SHRINK(oparg);
+            STACK_GROW(1);
+            POKE(1, str);
             DISPATCH();
         }
 
diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
index fd6f6164888dec..1e128c2c1478ca 100644
--- a/Python/opcode_metadata.h
+++ b/Python/opcode_metadata.h
@@ -88,7 +88,7 @@ static const struct {
     [LOAD_DEREF] = { 0, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [STORE_DEREF] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [COPY_FREE_VARS] = { 0, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
-    [BUILD_STRING] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
+    [BUILD_STRING] = { 1, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_TUPLE] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_LIST] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [LIST_EXTEND] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 8eb64fb4e6df0c..6d7c62d8cb63c4 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -84,16 +84,18 @@ def block(self, head: str):
         self.emit("}")
 
     def stack_adjust(self, diff: int, symbolic: list[str]):
+        # First emit all the pops, then all the pushes.
+        # The symbolic ones go at the ends.
+        for sym in symbolic:
+            if sym.startswith("-"):
+                self.emit(f"STACK_SHRINK({sym[1:]});")
+        if diff < 0:
+            self.emit(f"STACK_SHRINK({-diff});")
         if diff > 0:
             self.emit(f"STACK_GROW({diff});")
-        elif diff < 0:
-            self.emit(f"STACK_SHRINK({-diff});")
-        if symbolic:
-            for sym in symbolic:
-                if sym.startswith("-"):
-                    self.emit(f"STACK_SHRINK({sym[1:]});")
-                else:
-                    self.emit(f"STACK_GROW({sym});")
+        for sym in symbolic:
+            if not sym.startswith("-"):
+                self.emit(f"STACK_GROW({sym});")
 
     def declare(self, dst: StackEffect, src: StackEffect | None):
         if dst.name == UNUSED:
diff --git a/Tools/cases_generator/test_generator.py b/Tools/cases_generator/test_generator.py
index e7cc18c5f3cfe6..3a6631b4a3e528 100644
--- a/Tools/cases_generator/test_generator.py
+++ b/Tools/cases_generator/test_generator.py
@@ -311,15 +311,15 @@ def test_macro_instruction():
 
 def test_array_input():
     input = """
-        inst(OP, (values[oparg] --)) {
+        inst(OP, (values[oparg*2] --)) {
             spam();
         }
     """
     output = """
         TARGET(OP) {
-            PyObject **values = &PEEK(oparg);
+            PyObject **values = &PEEK(oparg*2);
             spam();
-            STACK_SHRINK(oparg);
+            STACK_SHRINK(oparg*2);
             DISPATCH();
         }
     """
@@ -327,7 +327,7 @@ def test_array_input():
 
 def test_array_output():
     input = """
-        inst(OP, (-- values[oparg])) {
+        inst(OP, (-- values[oparg*3])) {
             spam();
         }
     """
@@ -335,8 +335,8 @@ def test_array_output():
         TARGET(OP) {
             PyObject **values;
             spam();
-            STACK_GROW(oparg);
-            MOVE_ITEMS(values, &PEEK(oparg), oparg);
+            STACK_GROW(oparg*3);
+            MOVE_ITEMS(values, &PEEK(oparg*3), oparg*3);
             DISPATCH();
         }
     """

From bb53c44ce27f900d7001e5d32f4fd3708518c93f Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Fri, 6 Jan 2023 22:24:52 -0800
Subject: [PATCH 04/30] Ignore Context when comparing Nodes

---
 Tools/cases_generator/parser.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/cases_generator/parser.py b/Tools/cases_generator/parser.py
index 3b086413e46bff..932fe9f0f8f700 100644
--- a/Tools/cases_generator/parser.py
+++ b/Tools/cases_generator/parser.py
@@ -38,7 +38,7 @@ def __repr__(self):
 
 @dataclass
 class Node:
-    context: Context | None = field(init=False, default=None)
+    context: Context | None = field(init=False, compare=False, default=None)
 
     @property
     def text(self) -> str:

From 4a15c53942847f9b32cce1357736baacc25ae2d4 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Fri, 6 Jan 2023 22:40:32 -0800
Subject: [PATCH 05/30] Improve stack effect counting (TODO: use everywhere)

---
 Tools/cases_generator/generate_cases.py | 67 +++++++++++++++++++++----
 Tools/cases_generator/test_generator.py | 28 +++++++++++
 2 files changed, 86 insertions(+), 9 deletions(-)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 6d7c62d8cb63c4..df8722f41e7e1d 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -48,6 +48,53 @@
 )
 
 
+def effect_size(effect: StackEffect) -> tuple[int, str]:
+    if effect.size:
+        return 0, effect.size
+    else:
+        return 1, ""
+
+
+def list_effect_size(effects: list[StackEffect]) -> tuple[int, str]:
+    numeric = 0
+    symbolic: list[str] = []
+    for effect in effects:
+        diff, sym = effect_size(effect)
+        numeric += diff
+        if sym:
+            symbolic.append(sym)
+    return numeric, " + ".join(symbolic)
+
+
+def net_effect_size(input_effects: list[StackEffect], output_effects: list[StackEffect]) -> tuple[int, str]:
+    input_numeric, input_symbolic = list_effect_size(input_effects)
+    output_numeric, output_symbolic = list_effect_size(output_effects)
+    if "+" in input_symbolic:
+        input_symbolic = f"({input_symbolic})"
+    if input_symbolic and output_symbolic:
+        symbolic = f"{output_symbolic} - {input_symbolic}"
+    elif input_symbolic:
+        symbolic = f"-{input_symbolic}"
+    elif output_symbolic:
+        symbolic = output_symbolic
+    else:
+        symbolic = ""
+    return output_numeric - input_numeric, symbolic
+
+
+def string_effect_size(input_effects: list[StackEffect], output_effects: list[StackEffect]) -> str:
+    numeric, symbolic = net_effect_size(input_effects, output_effects)
+    if numeric and symbolic:
+        if symbolic.startswith("-"):
+            return f"{numeric} - {symbolic[1:]}"
+        else:
+            return f"{numeric} + {symbolic}"
+    elif symbolic:
+        return symbolic
+    else:
+        return str(numeric)
+
+
 class Formatter:
     """Wraps an output stream with the ability to indent etc."""
 
@@ -302,19 +349,21 @@ def write_body(self, out: Formatter, dedent: int, cache_adjust: int = 0) -> None
                 # The code block is responsible for DECREF()ing them.
                 # NOTE: If the label doesn't exist, just add it to ceval.c.
                 if not self.register:
-                    ninputs = len(self.input_effects)
                     # Don't pop common input/output effects at the bottom!
                     # These aren't DECREF'ed so they can stay.
-                    for ieff, oeff in zip(self.input_effects, self.output_effects):
-                        if ieff.name == oeff.name:
-                            ninputs -= 1
-                        else:
-                            break
+                    ieffs = list(self.input_effects)
+                    oeffs = list(self.output_effects)
+                    while ieffs and oeffs and ieffs[0] == oeffs[0]:
+                        ieffs.pop(0)
+                        oeffs.pop(0)
+                    ninputs, symbolic = list_effect_size(ieffs)
+                    if ninputs:
+                        label = f"pop_{ninputs}_{label}"
                 else:
-                    ninputs = 0
-                if ninputs:
+                    symbolic = ""
+                if symbolic:
                     out.write_raw(
-                        f"{extra}{space}if ({cond}) goto pop_{ninputs}_{label};\n"
+                        f"{extra}{space}if ({cond}) {{ STACK_SHRINK({symbolic}); goto {label}; }}\n"
                     )
                 else:
                     out.write_raw(f"{extra}{space}if ({cond}) goto {label};\n")
diff --git a/Tools/cases_generator/test_generator.py b/Tools/cases_generator/test_generator.py
index 3a6631b4a3e528..476f1706421835 100644
--- a/Tools/cases_generator/test_generator.py
+++ b/Tools/cases_generator/test_generator.py
@@ -4,6 +4,34 @@
 import tempfile
 
 import generate_cases
+from parser import StackEffect
+
+
+def test_effect_sizes():
+    input_effects = [
+        x := StackEffect("x", "", ""),
+        y := StackEffect("y", "", "oparg"),
+        z := StackEffect("z", "", "oparg*2"),
+    ]
+    output_effects = [
+        a := StackEffect("a", "", ""),
+        b := StackEffect("b", "", "oparg*4"),
+        c := StackEffect("c", "", ""),
+    ]
+    assert generate_cases.effect_size(x) == (1, "")
+    assert generate_cases.effect_size(y) == (0, "oparg")
+    assert generate_cases.effect_size(z) == (0, "oparg*2")
+
+    assert generate_cases.list_effect_size(input_effects) == (1, "oparg + oparg*2")
+    assert generate_cases.list_effect_size(output_effects) == (2, "oparg*4")
+
+    assert generate_cases.net_effect_size(input_effects, []) == (-1, "-(oparg + oparg*2)")
+    assert generate_cases.net_effect_size(input_effects, output_effects) == (1, "oparg*4 - (oparg + oparg*2)")
+    assert generate_cases.net_effect_size([], output_effects) == (2, "oparg*4")
+
+    assert generate_cases.string_effect_size(input_effects, []) == "-1 - (oparg + oparg*2)"
+    assert generate_cases.string_effect_size(input_effects, output_effects) == "1 + oparg*4 - (oparg + oparg*2)"
+    assert generate_cases.string_effect_size([], output_effects) == "2 + oparg*4"
 
 
 def run_cases_test(input: str, expected: str):

From 0a1e9a2c7105afff94a4468a4b5a2821367f2220 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Sat, 7 Jan 2023 16:54:04 -0800
Subject: [PATCH 06/30] Fix stack effect counting in most places

---
 Tools/cases_generator/generate_cases.py | 80 +++++++++++++------------
 Tools/cases_generator/test_generator.py | 77 +++++++++++++++++++++---
 2 files changed, 111 insertions(+), 46 deletions(-)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index df8722f41e7e1d..d37080ee4b4b42 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -82,8 +82,8 @@ def net_effect_size(input_effects: list[StackEffect], output_effects: list[Stack
     return output_numeric - input_numeric, symbolic
 
 
-def string_effect_size(input_effects: list[StackEffect], output_effects: list[StackEffect]) -> str:
-    numeric, symbolic = net_effect_size(input_effects, output_effects)
+def string_effect_size(arg: tuple[int, str]) -> str:
+    numeric, symbolic = arg
     if numeric and symbolic:
         if symbolic.startswith("-"):
             return f"{numeric} - {symbolic[1:]}"
@@ -130,19 +130,19 @@ def block(self, head: str):
             yield
         self.emit("}")
 
-    def stack_adjust(self, diff: int, symbolic: list[str]):
-        # First emit all the pops, then all the pushes.
-        # The symbolic ones go at the ends.
-        for sym in symbolic:
-            if sym.startswith("-"):
-                self.emit(f"STACK_SHRINK({sym[1:]});")
+    def stack_adjust(self, diff: int, input_effects: list[StackEffect], output_effects: list[StackEffect]):
+        # TODO: Get rid of 'diff' parameter
+        shrink, isym = list_effect_size(input_effects)
+        grow, osym = list_effect_size(output_effects)
+        diff += grow - shrink
+        if isym and isym != osym:
+            self.emit(f"STACK_SHRINK({isym});")
         if diff < 0:
             self.emit(f"STACK_SHRINK({-diff});")
         if diff > 0:
             self.emit(f"STACK_GROW({diff});")
-        for sym in symbolic:
-            if not sym.startswith("-"):
-                self.emit(f"STACK_GROW({sym});")
+        if osym and osym != isym:
+            self.emit(f"STACK_GROW({osym});")
 
     def declare(self, dst: StackEffect, src: StackEffect | None):
         if dst.name == UNUSED:
@@ -159,13 +159,13 @@ def assign(self, dst: StackEffect, src: StackEffect):
         if src.name == UNUSED:
             return
         cast = self.cast(dst, src)
-        if m := re.match(r"^PEEK\((\d+)\)$", dst.name):
+        if m := re.match(r"^PEEK\((.*)\)$", dst.name):
             self.emit(f"POKE({m.group(1)}, {cast}{src.name});")
         elif m := re.match(r"^&PEEK\(.*\)$", dst.name):
-            # NOTE: MOVE_ITEMS() does not exist.
+            # NOTE: MOVE_ITEMS() does not actually exist.
             # The only supported output array forms are:
             # - unused[...]
-            # - X[...] where X[...] matches an input array form
+            # - X[...] where X[...] matches an i99nput array form
             self.emit(f"MOVE_ITEMS({src.name}, {dst.name}, {src.size});")
         elif m := re.match(r"^REG\(oparg(\d+)\)$", dst.name):
             self.emit(f"Py_XSETREF({dst.name}, {cast}{src.name});")
@@ -245,7 +245,6 @@ def analyze_registers(self, a: "Analyzer") -> None:
     def write(self, out: Formatter) -> None:
         """Write one instruction, sans prologue and epilogue."""
         # Write a static assertion that a family's cache size is correct
-
         if family := self.family:
             if self.name == family.members[0]:
                 if cache_size := family.size:
@@ -256,11 +255,14 @@ def write(self, out: Formatter) -> None:
 
         if not self.register:
             # Write input stack effect variable declarations and initializations
-            for i, ieffect in enumerate(reversed(self.input_effects), 1):
+            ieffects = list(reversed(self.input_effects))
+            for i in range(len(ieffects)):
+                ieffect = ieffects[i]
+                isize = string_effect_size(list_effect_size(ieffects[:i+1]))
                 if ieffect.size:
-                    src = StackEffect(f"&PEEK({ieffect.size})", "PyObject **")
+                    src = StackEffect(f"&PEEK({isize})", "PyObject **")
                 else:
-                    src = StackEffect(f"PEEK({i})", "")
+                    src = StackEffect(f"PEEK({isize})", "")
                 out.declare(ieffect, src)
         else:
             # Write input register variable declarations and initializations
@@ -284,28 +286,20 @@ def write(self, out: Formatter) -> None:
 
         if not self.register:
             # Write net stack growth/shrinkage
-            diff = 0
-            symbolic: list[str] = []
-            for ieff in self.input_effects:
-                if ieff.size:
-                    symbolic.append(f"-{ieff.size}")
-                else:
-                    diff -= 1
-            for oeff in self.output_effects:
-                if oeff.size:
-                    symbolic.append(oeff.size)
-                else:
-                    diff += 1
-            out.stack_adjust(diff, symbolic)
+            out.stack_adjust(0, self.input_effects, self.output_effects)
 
             # Write output stack effect assignments
-            for i, oeffect in enumerate(reversed(self.output_effects), 1):
-                if oeffect.name not in self.unmoved_names:
-                    if oeffect.size:
-                        dst = StackEffect(f"&PEEK({oeffect.size})", "PyObject **")
-                    else:
-                        dst = StackEffect(f"PEEK({i})", "")
-                    out.assign(dst, oeffect)
+            oeffects = list(reversed(self.output_effects))
+            for i in range(len(oeffects)):
+                oeffect = oeffects[i]
+                if oeffect.name in self.unmoved_names:
+                    continue
+                osize = string_effect_size(list_effect_size(oeffects[:i+1]))
+                if oeffect.size:
+                    dst = StackEffect(f"&PEEK({osize})", "PyObject **")
+                else:
+                    dst = StackEffect(f"PEEK({osize})", "")
+                out.assign(dst, oeffect)
         else:
             # Write output register assignments
             for oeffect, reg in zip(self.output_effects, self.output_registers):
@@ -684,6 +678,12 @@ def stack_analysis(
         for thing in components:
             match thing:
                 case Instruction() as instr:
+                    if any(eff.size for eff in instr.input_effects + instr.output_effects):
+                        self.error(
+                            f"Instruction {instr.name!r} has variable-sized stack effect, "
+                            "which are not supported in super- or macro instructions",
+                            instr.inst,  # TODO: Pass name+location of super/macro
+                        )
                     current -= len(instr.input_effects)
                     lowest = min(lowest, current)
                     current += len(instr.output_effects)
@@ -924,7 +924,9 @@ def wrap_super_or_macro(self, up: SuperOrMacroInstruction):
 
             yield
 
-            self.out.stack_adjust(up.final_sp - up.initial_sp, [])
+            # TODO: Use slices of up.stack instead of numeric values
+            self.out.stack_adjust(up.final_sp - up.initial_sp, [], [])
+
             for i, var in enumerate(reversed(up.stack[: up.final_sp]), 1):
                 dst = StackEffect(f"PEEK({i})", "")
                 self.out.assign(dst, var)
diff --git a/Tools/cases_generator/test_generator.py b/Tools/cases_generator/test_generator.py
index 476f1706421835..ff91edd8ecfce9 100644
--- a/Tools/cases_generator/test_generator.py
+++ b/Tools/cases_generator/test_generator.py
@@ -29,9 +29,9 @@ def test_effect_sizes():
     assert generate_cases.net_effect_size(input_effects, output_effects) == (1, "oparg*4 - (oparg + oparg*2)")
     assert generate_cases.net_effect_size([], output_effects) == (2, "oparg*4")
 
-    assert generate_cases.string_effect_size(input_effects, []) == "-1 - (oparg + oparg*2)"
-    assert generate_cases.string_effect_size(input_effects, output_effects) == "1 + oparg*4 - (oparg + oparg*2)"
-    assert generate_cases.string_effect_size([], output_effects) == "2 + oparg*4"
+    assert generate_cases.string_effect_size(generate_cases.list_effect_size(input_effects)) == "1 + oparg + oparg*2"
+    assert generate_cases.string_effect_size(generate_cases.net_effect_size(input_effects, output_effects)) == "1 + oparg*4 - (oparg + oparg*2)"
+    assert generate_cases.string_effect_size(generate_cases.list_effect_size(output_effects)) == "2 + oparg*4"
 
 
 def run_cases_test(input: str, expected: str):
@@ -151,6 +151,24 @@ def test_binary_op():
     """
     run_cases_test(input, output)
 
+def test_overlap():
+    input = """
+        inst(OP, (left, right -- left, result)) {
+            spam();
+        }
+    """
+    output = """
+        TARGET(OP) {
+            PyObject *right = PEEK(1);
+            PyObject *left = PEEK(2);
+            PyObject *result;
+            spam();
+            POKE(1, result);
+            DISPATCH();
+        }
+    """
+    run_cases_test(input, output)
+
 def test_predictions():
     input = """
         inst(OP1, (--)) {
@@ -339,15 +357,18 @@ def test_macro_instruction():
 
 def test_array_input():
     input = """
-        inst(OP, (values[oparg*2] --)) {
+        inst(OP, (below, values[oparg*2], above --)) {
             spam();
         }
     """
     output = """
         TARGET(OP) {
-            PyObject **values = &PEEK(oparg*2);
+            PyObject *above = PEEK(1);
+            PyObject **values = &PEEK(1 + oparg*2);
+            PyObject *below = PEEK(2 + oparg*2);
             spam();
             STACK_SHRINK(oparg*2);
+            STACK_SHRINK(2);
             DISPATCH();
         }
     """
@@ -355,16 +376,58 @@ def test_array_input():
 
 def test_array_output():
     input = """
-        inst(OP, (-- values[oparg*3])) {
+        inst(OP, (-- below, values[oparg*3], above)) {
             spam();
         }
     """
     output = """
         TARGET(OP) {
+            PyObject *below;
             PyObject **values;
+            PyObject *above;
             spam();
+            STACK_GROW(2);
             STACK_GROW(oparg*3);
-            MOVE_ITEMS(values, &PEEK(oparg*3), oparg*3);
+            POKE(1, above);
+            MOVE_ITEMS(values, &PEEK(1 + oparg*3), oparg*3);
+            POKE(2 + oparg*3, below);
+            DISPATCH();
+        }
+    """
+    run_cases_test(input, output)
+
+def test_array_input_output():
+    input = """
+        inst(OP, (below, values[oparg] -- values[oparg], above)) {
+            spam();
+        }
+    """
+    output = """
+        TARGET(OP) {
+            PyObject **values = &PEEK(oparg);
+            PyObject *below = PEEK(1 + oparg);
+            PyObject *above;
+            spam();
+            POKE(1, above);
+            MOVE_ITEMS(values, &PEEK(1 + oparg), oparg);
+            DISPATCH();
+        }
+    """
+    run_cases_test(input, output)
+
+def test_array_error_if():
+    input = """
+        inst(OP, (extra, values[oparg] --)) {
+            ERROR_IF(oparg == 0, somewhere);
+        }
+    """
+    output = """
+        TARGET(OP) {
+            PyObject **values = &PEEK(oparg);
+            PyObject *extra = PEEK(1 + oparg);
+            if (oparg == 0) { STACK_SHRINK(oparg); goto pop_1_somewhere; }
+            STACK_SHRINK(oparg);
+            STACK_SHRINK(1);
             DISPATCH();
         }
     """

From b02323600b1c267d22dbbbe683ec0c559b4c4b7e Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Sun, 8 Jan 2023 21:34:25 -0800
Subject: [PATCH 07/30] Fix TODO

---
 Tools/cases_generator/parser.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/cases_generator/parser.py b/Tools/cases_generator/parser.py
index 932fe9f0f8f700..cdac80378d04a9 100644
--- a/Tools/cases_generator/parser.py
+++ b/Tools/cases_generator/parser.py
@@ -231,7 +231,7 @@ def cache_effect(self) -> CacheEffect | None:
     @contextual
     def stack_effect(self) -> StackEffect | None:
         # IDENTIFIER [':' IDENTIFIER]
-        # TODO: Arrays, conditions
+        # TODO: Conditions
         if tkn := self.expect(lx.IDENTIFIER):
             if self.expect(lx.COLON):
                 typ = self.require(lx.IDENTIFIER)

From 9ec91e19fc17e51ab33e31fa7a49a40b50dac05b Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Sun, 8 Jan 2023 21:34:35 -0800
Subject: [PATCH 08/30] Fix opcode metadata for array stack effects

---
 Python/compile.c                        | 2 +-
 Python/opcode_metadata.h                | 2 +-
 Tools/cases_generator/generate_cases.py | 8 ++++++--
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/Python/compile.c b/Python/compile.c
index 6d176a83a87acc..62f889eb35a557 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -8873,7 +8873,7 @@ assemble(struct compiler *c, int addNone)
     }
 
     assert(no_redundant_jumps(g));
-    // assert(opcode_metadata_is_sane(g));
+    assert(opcode_metadata_is_sane(g));
 
     /* Can't modify the bytecode after computing jump offsets. */
     assemble_jump_offsets(g->g_entryblock);
diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
index 1e128c2c1478ca..fd6f6164888dec 100644
--- a/Python/opcode_metadata.h
+++ b/Python/opcode_metadata.h
@@ -88,7 +88,7 @@ static const struct {
     [LOAD_DEREF] = { 0, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [STORE_DEREF] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [COPY_FREE_VARS] = { 0, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
-    [BUILD_STRING] = { 1, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
+    [BUILD_STRING] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_TUPLE] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_LIST] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [LIST_EXTEND] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index d37080ee4b4b42..f803488743ab49 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -679,6 +679,7 @@ def stack_analysis(
             match thing:
                 case Instruction() as instr:
                     if any(eff.size for eff in instr.input_effects + instr.output_effects):
+                        # TODO: Eventually this will be needed, at least for macros.
                         self.error(
                             f"Instruction {instr.name!r} has variable-sized stack effect, "
                             "which are not supported in super- or macro instructions",
@@ -792,8 +793,11 @@ def write_metadata_for_inst(self, instr: Instruction) -> None:
             n_popped = n_pushed = -1
             assert not instr.register
         else:
-            n_popped = len(instr.input_effects)
-            n_pushed = len(instr.output_effects)
+            n_popped, sym_popped = list_effect_size(instr.input_effects)
+            n_pushed, sym_pushed = list_effect_size(instr.output_effects)
+            if sym_popped or sym_pushed:
+                # TODO: Record symbolic effects (how?)
+                n_popped = n_pushed = -1
             if instr.register:
                 directions: list[str] = []
                 directions.extend("DIR_READ" for _ in instr.input_effects)

From af785de41a0a5a008898314f08befb0ba4241962 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Mon, 9 Jan 2023 16:09:47 -0800
Subject: [PATCH 09/30] Array-ize LIST_APPEND

---
 Python/bytecodes.c         | 7 +++----
 Python/generated_cases.c.h | 4 ++--
 Python/opcode_metadata.h   | 2 +-
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index f86649f64870b6..904b7f881d5e62 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -456,10 +456,9 @@ dummy_func(
             DISPATCH_INLINED(new_frame);
         }
 
-        // Alternative: (list, unused[oparg], v -- list, unused[oparg])
-        inst(LIST_APPEND, (v --)) {
-            PyObject *list = PEEK(oparg + 1);  // +1 to account for v staying on stack
-            ERROR_IF(_PyList_AppendTakeRef((PyListObject *)list, v) < 0, error);
+        // 'stuff' is a list object followed by (oparg - 1) unused values
+        inst(LIST_APPEND, (stuff[oparg], v -- stuff[oparg])) {
+            ERROR_IF(_PyList_AppendTakeRef((PyListObject *)stuff[0], v) < 0, error);
             PREDICT(JUMP_BACKWARD);
         }
 
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 818bc68ad45086..32e424f0b932c6 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -574,8 +574,8 @@
 
         TARGET(LIST_APPEND) {
             PyObject *v = PEEK(1);
-            PyObject *list = PEEK(oparg + 1);  // +1 to account for v staying on stack
-            if (_PyList_AppendTakeRef((PyListObject *)list, v) < 0) goto pop_1_error;
+            PyObject **stuff = &PEEK(1 + oparg);
+            if (_PyList_AppendTakeRef((PyListObject *)stuff[0], v) < 0) goto pop_1_error;
             STACK_SHRINK(1);
             PREDICT(JUMP_BACKWARD);
             DISPATCH();
diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
index fd6f6164888dec..4816439321bbd2 100644
--- a/Python/opcode_metadata.h
+++ b/Python/opcode_metadata.h
@@ -44,7 +44,7 @@ static const struct {
     [BINARY_SUBSCR_TUPLE_INT] = { 2, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC000" },
     [BINARY_SUBSCR_DICT] = { 2, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC000" },
     [BINARY_SUBSCR_GETITEM] = { 2, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC000" },
-    [LIST_APPEND] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
+    [LIST_APPEND] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [SET_ADD] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [STORE_SUBSCR] = { 3, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC" },
     [STORE_SUBSCR_LIST_INT] = { 3, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC" },

From 4fddf2b5952e53cd0ded93009cec1942d4d6331e Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Mon, 9 Jan 2023 16:38:53 -0800
Subject: [PATCH 10/30] Array-ize SET_ADD

---
 Python/bytecodes.c         | 7 +++----
 Python/generated_cases.c.h | 4 ++--
 Python/opcode_metadata.h   | 2 +-
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 904b7f881d5e62..139fc57ebc02cc 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -462,10 +462,9 @@ dummy_func(
             PREDICT(JUMP_BACKWARD);
         }
 
-        // Alternative: (set, unused[oparg], v -- set, unused[oparg])
-        inst(SET_ADD, (v --)) {
-            PyObject *set = PEEK(oparg + 1);  // +1 to account for v staying on stack
-            int err = PySet_Add(set, v);
+        // Ditto
+        inst(SET_ADD,  (stuff[oparg], v -- stuff[oparg])) {
+            int err = PySet_Add(stuff[0], v);
             Py_DECREF(v);
             ERROR_IF(err, error);
             PREDICT(JUMP_BACKWARD);
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 32e424f0b932c6..46588a914c9a15 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -583,8 +583,8 @@
 
         TARGET(SET_ADD) {
             PyObject *v = PEEK(1);
-            PyObject *set = PEEK(oparg + 1);  // +1 to account for v staying on stack
-            int err = PySet_Add(set, v);
+            PyObject **stuff = &PEEK(1 + oparg);
+            int err = PySet_Add(stuff[0], v);
             Py_DECREF(v);
             if (err) goto pop_1_error;
             STACK_SHRINK(1);
diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
index 4816439321bbd2..0cf40426eb5f15 100644
--- a/Python/opcode_metadata.h
+++ b/Python/opcode_metadata.h
@@ -45,7 +45,7 @@ static const struct {
     [BINARY_SUBSCR_DICT] = { 2, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC000" },
     [BINARY_SUBSCR_GETITEM] = { 2, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC000" },
     [LIST_APPEND] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
-    [SET_ADD] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
+    [SET_ADD] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [STORE_SUBSCR] = { 3, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC" },
     [STORE_SUBSCR_LIST_INT] = { 3, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC" },
     [STORE_SUBSCR_DICT] = { 3, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IBC" },

From ac221153f7ce83b113bd4acab589df5de1b6f254 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Mon, 9 Jan 2023 16:42:18 -0800
Subject: [PATCH 11/30] Array-ize LIST_EXTEND

---
 Python/bytecodes.c         | 6 +++---
 Python/generated_cases.c.h | 4 ++--
 Python/opcode_metadata.h   | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 139fc57ebc02cc..9b509d7ebb5a0a 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1325,9 +1325,9 @@ dummy_func(
             PUSH(list);
         }
 
-        inst(LIST_EXTEND, (iterable -- )) {
-            PyObject *list = PEEK(oparg + 1);  // iterable is still on the stack
-            PyObject *none_val = _PyList_Extend((PyListObject *)list, iterable);
+        // 'stuff' is a list object followed by (oparg - 1) unused values
+        inst(LIST_EXTEND, (stuff[oparg], iterable -- stuff[oparg])) {
+            PyObject *none_val = _PyList_Extend((PyListObject *)stuff[0], iterable);
             if (none_val == NULL) {
                 if (_PyErr_ExceptionMatches(tstate, PyExc_TypeError) &&
                    (Py_TYPE(iterable)->tp_iter == NULL && !PySequence_Check(iterable)))
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 46588a914c9a15..c227eb20d5ec80 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1545,8 +1545,8 @@
 
         TARGET(LIST_EXTEND) {
             PyObject *iterable = PEEK(1);
-            PyObject *list = PEEK(oparg + 1);  // iterable is still on the stack
-            PyObject *none_val = _PyList_Extend((PyListObject *)list, iterable);
+            PyObject **stuff = &PEEK(1 + oparg);
+            PyObject *none_val = _PyList_Extend((PyListObject *)stuff[0], iterable);
             if (none_val == NULL) {
                 if (_PyErr_ExceptionMatches(tstate, PyExc_TypeError) &&
                    (Py_TYPE(iterable)->tp_iter == NULL && !PySequence_Check(iterable)))
diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
index 0cf40426eb5f15..cf96d753482884 100644
--- a/Python/opcode_metadata.h
+++ b/Python/opcode_metadata.h
@@ -91,7 +91,7 @@ static const struct {
     [BUILD_STRING] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_TUPLE] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_LIST] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
-    [LIST_EXTEND] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
+    [LIST_EXTEND] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [SET_UPDATE] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_SET] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_MAP] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },

From 6c83be037346e4ed1b5b45c5b4fbf3608b9058de Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Mon, 9 Jan 2023 16:46:58 -0800
Subject: [PATCH 12/30] Array-ize SET_UPDATE

---
 Python/bytecodes.c         | 8 ++++----
 Python/generated_cases.c.h | 4 ++--
 Python/opcode_metadata.h   | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 9b509d7ebb5a0a..3319d29257b3c1 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -462,7 +462,7 @@ dummy_func(
             PREDICT(JUMP_BACKWARD);
         }
 
-        // Ditto
+        // 'stuff' is a set object followed by (oparg - 1) unused values
         inst(SET_ADD,  (stuff[oparg], v -- stuff[oparg])) {
             int err = PySet_Add(stuff[0], v);
             Py_DECREF(v);
@@ -1344,9 +1344,9 @@ dummy_func(
             DECREF_INPUTS();
         }
 
-        inst(SET_UPDATE, (iterable --)) {
-            PyObject *set = PEEK(oparg + 1);  // iterable is still on the stack
-            int err = _PySet_Update(set, iterable);
+        // 'stuff' is a set object followed by (oparg - 1) unused values
+        inst(SET_UPDATE, (stuff[oparg], iterable -- stuff[oparg])) {
+            int err = _PySet_Update(stuff[0], iterable);
             DECREF_INPUTS();
             ERROR_IF(err < 0, error);
         }
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index c227eb20d5ec80..4b8828fa00376c 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1567,8 +1567,8 @@
 
         TARGET(SET_UPDATE) {
             PyObject *iterable = PEEK(1);
-            PyObject *set = PEEK(oparg + 1);  // iterable is still on the stack
-            int err = _PySet_Update(set, iterable);
+            PyObject **stuff = &PEEK(1 + oparg);
+            int err = _PySet_Update(stuff[0], iterable);
             Py_DECREF(iterable);
             if (err < 0) goto pop_1_error;
             STACK_SHRINK(1);
diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
index cf96d753482884..4396bb6ccd0d77 100644
--- a/Python/opcode_metadata.h
+++ b/Python/opcode_metadata.h
@@ -92,7 +92,7 @@ static const struct {
     [BUILD_TUPLE] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_LIST] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [LIST_EXTEND] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
-    [SET_UPDATE] = { 1, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
+    [SET_UPDATE] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_SET] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [BUILD_MAP] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },
     [SETUP_ANNOTATIONS] = { 0, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, "IB" },

From c7999dd43f69abf6a429776605a968888f7d366e Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Mon, 9 Jan 2023 21:08:49 -0800
Subject: [PATCH 13/30] Array-ize BUILD_TUPLE

---
 Python/bytecodes.c         | 10 +++-------
 Python/generated_cases.c.h | 10 ++++++----
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 3319d29257b3c1..a54109331bf51d 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1307,13 +1307,9 @@ dummy_func(
             }
         }
 
-        // stack effect: (__array[oparg] -- __0)
-        inst(BUILD_TUPLE) {
-            STACK_SHRINK(oparg);
-            PyObject *tup = _PyTuple_FromArraySteal(stack_pointer, oparg);
-            if (tup == NULL)
-                goto error;
-            PUSH(tup);
+        inst(BUILD_TUPLE, (values[oparg] -- tup)) {
+            tup = _PyTuple_FromArraySteal(values, oparg);
+            ERROR_IF(tup == NULL, error);
         }
 
         // stack effect: (__array[oparg] -- __0)
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 4b8828fa00376c..963ee474008674 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1526,11 +1526,13 @@
         }
 
         TARGET(BUILD_TUPLE) {
+            PyObject **values = &PEEK(oparg);
+            PyObject *tup;
+            tup = _PyTuple_FromArraySteal(values, oparg);
+            if (tup == NULL) { STACK_SHRINK(oparg); goto error; }
             STACK_SHRINK(oparg);
-            PyObject *tup = _PyTuple_FromArraySteal(stack_pointer, oparg);
-            if (tup == NULL)
-                goto error;
-            PUSH(tup);
+            STACK_GROW(1);
+            POKE(1, tup);
             DISPATCH();
         }
 

From a7aa4257d055959f9a75f01f7a2bf1cdf09bc115 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Mon, 9 Jan 2023 21:10:09 -0800
Subject: [PATCH 14/30] Array-ize BUILD_LIST

---
 Python/bytecodes.c         | 10 +++-------
 Python/generated_cases.c.h | 10 ++++++----
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index a54109331bf51d..b042f2d9817ecb 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1312,13 +1312,9 @@ dummy_func(
             ERROR_IF(tup == NULL, error);
         }
 
-        // stack effect: (__array[oparg] -- __0)
-        inst(BUILD_LIST) {
-            STACK_SHRINK(oparg);
-            PyObject *list = _PyList_FromArraySteal(stack_pointer, oparg);
-            if (list == NULL)
-                goto error;
-            PUSH(list);
+        inst(BUILD_LIST, (values[oparg] -- list)) {
+            list = _PyList_FromArraySteal(values, oparg);
+            ERROR_IF(list == NULL, error);
         }
 
         // 'stuff' is a list object followed by (oparg - 1) unused values
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 963ee474008674..4df08336315f5f 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1537,11 +1537,13 @@
         }
 
         TARGET(BUILD_LIST) {
+            PyObject **values = &PEEK(oparg);
+            PyObject *list;
+            list = _PyList_FromArraySteal(values, oparg);
+            if (list == NULL) { STACK_SHRINK(oparg); goto error; }
             STACK_SHRINK(oparg);
-            PyObject *list = _PyList_FromArraySteal(stack_pointer, oparg);
-            if (list == NULL)
-                goto error;
-            PUSH(list);
+            STACK_GROW(1);
+            POKE(1, list);
             DISPATCH();
         }
 

From 11f6a583a6729a68413ab9c6321b0884acad03bf Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Mon, 9 Jan 2023 21:15:42 -0800
Subject: [PATCH 15/30] Use ERROR_IF() in BUILD_STRING

---
 Python/bytecodes.c         | 3 +--
 Python/generated_cases.c.h | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index b042f2d9817ecb..df4a5fc2bc73ee 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1300,11 +1300,10 @@ dummy_func(
 
         inst(BUILD_STRING, (pieces[oparg] -- str)) {
             str = _PyUnicode_JoinArray(&_Py_STR(empty), pieces, oparg);
-            if (str == NULL)
-                goto error;
             for (int i = 0; i < oparg; i++) {
                 Py_DECREF(pieces[i]);
             }
+            ERROR_IF(str == NULL, error);
         }
 
         inst(BUILD_TUPLE, (values[oparg] -- tup)) {
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 4df08336315f5f..9bb94d6efbe2d1 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1514,11 +1514,10 @@
             PyObject **pieces = &PEEK(oparg);
             PyObject *str;
             str = _PyUnicode_JoinArray(&_Py_STR(empty), pieces, oparg);
-            if (str == NULL)
-                goto error;
             for (int i = 0; i < oparg; i++) {
                 Py_DECREF(pieces[i]);
             }
+            if (str == NULL) { STACK_SHRINK(oparg); goto error; }
             STACK_SHRINK(oparg);
             STACK_GROW(1);
             POKE(1, str);

From abff4ae9f4b3d488bfa898c0fad5c07e88501f94 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 11 Jan 2023 21:57:21 -0800
Subject: [PATCH 16/30] Apply most suggestions from code review

---
 Tools/cases_generator/parser.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Tools/cases_generator/parser.py b/Tools/cases_generator/parser.py
index cdac80378d04a9..b5d39c2a155d00 100644
--- a/Tools/cases_generator/parser.py
+++ b/Tools/cases_generator/parser.py
@@ -230,7 +230,9 @@ def cache_effect(self) -> CacheEffect | None:
 
     @contextual
     def stack_effect(self) -> StackEffect | None:
-        # IDENTIFIER [':' IDENTIFIER]
+        # IDENTIFIER
+        #   | IDENTIFIER ':' IDENTIFIER
+        #   | IDENTIFIER '[' dimension ']'
         # TODO: Conditions
         if tkn := self.expect(lx.IDENTIFIER):
             if self.expect(lx.COLON):

From a02a9eb8a4257b11886a9b75476d6c2f8b890d56 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 11 Jan 2023 22:50:55 -0800
Subject: [PATCH 17/30] Accept more general dimensions

---
 Tools/cases_generator/generate_cases.py | 21 +--------------------
 Tools/cases_generator/parser.py         | 14 ++++++--------
 Tools/cases_generator/test_generator.py |  5 -----
 3 files changed, 7 insertions(+), 33 deletions(-)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 2c2ead7290c342..c74c555fb320a0 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -66,29 +66,10 @@ def list_effect_size(effects: list[StackEffect]) -> tuple[int, str]:
     return numeric, " + ".join(symbolic)
 
 
-def net_effect_size(input_effects: list[StackEffect], output_effects: list[StackEffect]) -> tuple[int, str]:
-    input_numeric, input_symbolic = list_effect_size(input_effects)
-    output_numeric, output_symbolic = list_effect_size(output_effects)
-    if "+" in input_symbolic:
-        input_symbolic = f"({input_symbolic})"
-    if input_symbolic and output_symbolic:
-        symbolic = f"{output_symbolic} - {input_symbolic}"
-    elif input_symbolic:
-        symbolic = f"-{input_symbolic}"
-    elif output_symbolic:
-        symbolic = output_symbolic
-    else:
-        symbolic = ""
-    return output_numeric - input_numeric, symbolic
-
-
 def string_effect_size(arg: tuple[int, str]) -> str:
     numeric, symbolic = arg
     if numeric and symbolic:
-        if symbolic.startswith("-"):
-            return f"{numeric} - {symbolic[1:]}"
-        else:
-            return f"{numeric} + {symbolic}"
+        return f"{numeric} + {symbolic}"
     elif symbolic:
         return symbolic
     else:
diff --git a/Tools/cases_generator/parser.py b/Tools/cases_generator/parser.py
index b5d39c2a155d00..56b8280845cd3f 100644
--- a/Tools/cases_generator/parser.py
+++ b/Tools/cases_generator/parser.py
@@ -70,9 +70,7 @@ class StackEffect(Node):
 
 @dataclass
 class Dimension(Node):
-    # NAME ['*' NUMBER]
-    name: str
-    size: int = 1
+    size: str
 
 
 @dataclass
@@ -248,11 +246,11 @@ def stack_effect(self) -> StackEffect | None:
 
     @contextual
     def dimension(self) -> Dimension | None:
-        if name := self.expect(lx.IDENTIFIER):
-            if self.expect(lx.TIMES):
-                if size := self.expect(lx.NUMBER):
-                    return Dimension(name.text, int(size.text))
-            return Dimension(name.text)
+        tokens: list[lx.Token] = []
+        while (tkn := self.peek()) and tkn.kind != lx.RBRACKET:
+            tokens.append(tkn)
+            self.next()
+        return Dimension(lx.to_text(tokens).strip())
 
     @contextual
     def super_def(self) -> Super | None:
diff --git a/Tools/cases_generator/test_generator.py b/Tools/cases_generator/test_generator.py
index ff91edd8ecfce9..dd7b77e268b9c2 100644
--- a/Tools/cases_generator/test_generator.py
+++ b/Tools/cases_generator/test_generator.py
@@ -25,12 +25,7 @@ def test_effect_sizes():
     assert generate_cases.list_effect_size(input_effects) == (1, "oparg + oparg*2")
     assert generate_cases.list_effect_size(output_effects) == (2, "oparg*4")
 
-    assert generate_cases.net_effect_size(input_effects, []) == (-1, "-(oparg + oparg*2)")
-    assert generate_cases.net_effect_size(input_effects, output_effects) == (1, "oparg*4 - (oparg + oparg*2)")
-    assert generate_cases.net_effect_size([], output_effects) == (2, "oparg*4")
-
     assert generate_cases.string_effect_size(generate_cases.list_effect_size(input_effects)) == "1 + oparg + oparg*2"
-    assert generate_cases.string_effect_size(generate_cases.net_effect_size(input_effects, output_effects)) == "1 + oparg*4 - (oparg + oparg*2)"
     assert generate_cases.string_effect_size(generate_cases.list_effect_size(output_effects)) == "2 + oparg*4"
 
 

From 2bcd90f818fb845041202084f91d3c1e33da6bae Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 11 Jan 2023 22:51:26 -0800
Subject: [PATCH 18/30] Fix LIST_EXTEND

---
 Python/bytecodes.c         | 5 ++---
 Python/generated_cases.c.h | 4 ++--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index df4a5fc2bc73ee..675d2500b2bec5 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1316,9 +1316,8 @@ dummy_func(
             ERROR_IF(list == NULL, error);
         }
 
-        // 'stuff' is a list object followed by (oparg - 1) unused values
-        inst(LIST_EXTEND, (stuff[oparg], iterable -- stuff[oparg])) {
-            PyObject *none_val = _PyList_Extend((PyListObject *)stuff[0], iterable);
+        inst(LIST_EXTEND, (list, unused[oparg-1], iterable -- list, unused[oparg-1])) {
+            PyObject *none_val = _PyList_Extend((PyListObject *)list, iterable);
             if (none_val == NULL) {
                 if (_PyErr_ExceptionMatches(tstate, PyExc_TypeError) &&
                    (Py_TYPE(iterable)->tp_iter == NULL && !PySequence_Check(iterable)))
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 9bb94d6efbe2d1..81020f032474e6 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1548,8 +1548,8 @@
 
         TARGET(LIST_EXTEND) {
             PyObject *iterable = PEEK(1);
-            PyObject **stuff = &PEEK(1 + oparg);
-            PyObject *none_val = _PyList_Extend((PyListObject *)stuff[0], iterable);
+            PyObject *list = PEEK(2 + oparg-1);
+            PyObject *none_val = _PyList_Extend((PyListObject *)list, iterable);
             if (none_val == NULL) {
                 if (_PyErr_ExceptionMatches(tstate, PyExc_TypeError) &&
                    (Py_TYPE(iterable)->tp_iter == NULL && !PySequence_Check(iterable)))

From c579a40d654b7a8e9a3cc9be0664b995b2fcd664 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 11 Jan 2023 23:08:05 -0800
Subject: [PATCH 19/30] Fix LIST_APPEND, SET_ADD, SET_UPDATE

---
 Python/bytecodes.c         | 15 ++++++---------
 Python/generated_cases.c.h | 12 ++++++------
 2 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 675d2500b2bec5..fbb015df52f1f4 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -456,15 +456,13 @@ dummy_func(
             DISPATCH_INLINED(new_frame);
         }
 
-        // 'stuff' is a list object followed by (oparg - 1) unused values
-        inst(LIST_APPEND, (stuff[oparg], v -- stuff[oparg])) {
-            ERROR_IF(_PyList_AppendTakeRef((PyListObject *)stuff[0], v) < 0, error);
+        inst(LIST_APPEND, (list, unused[oparg-1], v -- list, unused[oparg-1])) {
+            ERROR_IF(_PyList_AppendTakeRef((PyListObject *)list, v) < 0, error);
             PREDICT(JUMP_BACKWARD);
         }
 
-        // 'stuff' is a set object followed by (oparg - 1) unused values
-        inst(SET_ADD,  (stuff[oparg], v -- stuff[oparg])) {
-            int err = PySet_Add(stuff[0], v);
+        inst(SET_ADD,  (set, unused[oparg-1], v -- set, unused[oparg-1])) {
+            int err = PySet_Add(set, v);
             Py_DECREF(v);
             ERROR_IF(err, error);
             PREDICT(JUMP_BACKWARD);
@@ -1334,9 +1332,8 @@ dummy_func(
             DECREF_INPUTS();
         }
 
-        // 'stuff' is a set object followed by (oparg - 1) unused values
-        inst(SET_UPDATE, (stuff[oparg], iterable -- stuff[oparg])) {
-            int err = _PySet_Update(stuff[0], iterable);
+        inst(SET_UPDATE, (set, unused[oparg-1], iterable -- set, unused[oparg-1])) {
+            int err = _PySet_Update(set, iterable);
             DECREF_INPUTS();
             ERROR_IF(err < 0, error);
         }
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 81020f032474e6..c0c78be86c8712 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -574,8 +574,8 @@
 
         TARGET(LIST_APPEND) {
             PyObject *v = PEEK(1);
-            PyObject **stuff = &PEEK(1 + oparg);
-            if (_PyList_AppendTakeRef((PyListObject *)stuff[0], v) < 0) goto pop_1_error;
+            PyObject *list = PEEK(2 + oparg-1);
+            if (_PyList_AppendTakeRef((PyListObject *)list, v) < 0) goto pop_1_error;
             STACK_SHRINK(1);
             PREDICT(JUMP_BACKWARD);
             DISPATCH();
@@ -583,8 +583,8 @@
 
         TARGET(SET_ADD) {
             PyObject *v = PEEK(1);
-            PyObject **stuff = &PEEK(1 + oparg);
-            int err = PySet_Add(stuff[0], v);
+            PyObject *set = PEEK(2 + oparg-1);
+            int err = PySet_Add(set, v);
             Py_DECREF(v);
             if (err) goto pop_1_error;
             STACK_SHRINK(1);
@@ -1570,8 +1570,8 @@
 
         TARGET(SET_UPDATE) {
             PyObject *iterable = PEEK(1);
-            PyObject **stuff = &PEEK(1 + oparg);
-            int err = _PySet_Update(stuff[0], iterable);
+            PyObject *set = PEEK(2 + oparg-1);
+            int err = _PySet_Update(set, iterable);
             Py_DECREF(iterable);
             if (err < 0) goto pop_1_error;
             STACK_SHRINK(1);

From 70e983df334dccf53791478759856de5100ccfc5 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Fri, 13 Jan 2023 17:36:12 -0800
Subject: [PATCH 20/30] Array-ize BUILD_SET

---
 Python/bytecodes.c         | 16 +++++-----------
 Python/generated_cases.c.h | 18 +++++++++---------
 2 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index f70e57da05add8..a184dd36fc7490 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1338,25 +1338,19 @@ dummy_func(
             ERROR_IF(err < 0, error);
         }
 
-        // stack effect: (__array[oparg] -- __0)
-        inst(BUILD_SET) {
-            PyObject *set = PySet_New(NULL);
+        inst(BUILD_SET, (values[oparg] -- set)) {
+            set = PySet_New(NULL);
             int err = 0;
-            int i;
-            if (set == NULL)
-                goto error;
-            for (i = oparg; i > 0; i--) {
-                PyObject *item = PEEK(i);
+            for (int i = 0; i < oparg; i++) {
+                PyObject *item = values[i];
                 if (err == 0)
                     err = PySet_Add(set, item);
                 Py_DECREF(item);
             }
-            STACK_SHRINK(oparg);
             if (err != 0) {
                 Py_DECREF(set);
-                goto error;
+                ERROR_IF(true, error);
             }
-            PUSH(set);
         }
 
         // stack effect: (__array[oparg*2] -- __0)
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index cfb29cbc72aa83..57117f69fcc3a7 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1579,23 +1579,23 @@
         }
 
         TARGET(BUILD_SET) {
-            PyObject *set = PySet_New(NULL);
+            PyObject **values = &PEEK(oparg);
+            PyObject *set;
+            set = PySet_New(NULL);
             int err = 0;
-            int i;
-            if (set == NULL)
-                goto error;
-            for (i = oparg; i > 0; i--) {
-                PyObject *item = PEEK(i);
+            for (int i = 0; i < oparg; i++) {
+                PyObject *item = values[i];
                 if (err == 0)
                     err = PySet_Add(set, item);
                 Py_DECREF(item);
             }
-            STACK_SHRINK(oparg);
             if (err != 0) {
                 Py_DECREF(set);
-                goto error;
+                if (true) { STACK_SHRINK(oparg); goto error; }
             }
-            PUSH(set);
+            STACK_SHRINK(oparg);
+            STACK_GROW(1);
+            POKE(1, set);
             DISPATCH();
         }
 

From 827481ee88d009104fff7d39e255e85a3f51faa8 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Fri, 13 Jan 2023 17:42:08 -0800
Subject: [PATCH 21/30] Array-ize BUILD_MAP

---
 Python/bytecodes.c         | 17 ++++++++---------
 Python/generated_cases.c.h | 19 ++++++++++++-------
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index a184dd36fc7490..8366aa85e3e7df 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1353,20 +1353,19 @@ dummy_func(
             }
         }
 
-        // stack effect: (__array[oparg*2] -- __0)
-        inst(BUILD_MAP) {
-            PyObject *map = _PyDict_FromItems(
-                    &PEEK(2*oparg), 2,
-                    &PEEK(2*oparg - 1), 2,
+        inst(BUILD_MAP, (values[oparg*2] -- map)) {
+            map = _PyDict_FromItems(
+                    values, 2,
+                    values+1, 2,
                     oparg);
             if (map == NULL)
                 goto error;
 
-            while (oparg--) {
-                Py_DECREF(POP());
-                Py_DECREF(POP());
+            for (int i = 0; i < oparg; i++) {
+                Py_DECREF(values[i*2]);
+                Py_DECREF(values[i*2+1]);
             }
-            PUSH(map);
+            ERROR_IF(map == NULL, error);
         }
 
         inst(SETUP_ANNOTATIONS, (--)) {
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 57117f69fcc3a7..d433f9d0264edd 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1600,18 +1600,23 @@
         }
 
         TARGET(BUILD_MAP) {
-            PyObject *map = _PyDict_FromItems(
-                    &PEEK(2*oparg), 2,
-                    &PEEK(2*oparg - 1), 2,
+            PyObject **values = &PEEK(oparg*2);
+            PyObject *map;
+            map = _PyDict_FromItems(
+                    values, 2,
+                    values+1, 2,
                     oparg);
             if (map == NULL)
                 goto error;
 
-            while (oparg--) {
-                Py_DECREF(POP());
-                Py_DECREF(POP());
+            for (int i = 0; i < oparg; i++) {
+                Py_DECREF(values[i*2]);
+                Py_DECREF(values[i*2+1]);
             }
-            PUSH(map);
+            if (map == NULL) { STACK_SHRINK(oparg*2); goto error; }
+            STACK_SHRINK(oparg*2);
+            STACK_GROW(1);
+            POKE(1, map);
             DISPATCH();
         }
 

From aa69c55b369e9e369c07c4a061abe9932020a98b Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Fri, 13 Jan 2023 17:51:29 -0800
Subject: [PATCH 22/30] Array-ize BUILD_CONST_KEY_MAP

---
 Python/bytecodes.c         | 21 +++++++--------------
 Python/generated_cases.c.h | 21 ++++++++++-----------
 2 files changed, 17 insertions(+), 25 deletions(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 8366aa85e3e7df..50d9e2e5923cb3 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1410,28 +1410,21 @@ dummy_func(
             }
         }
 
-        // stack effect: (__array[oparg] -- )
-        inst(BUILD_CONST_KEY_MAP) {
-            PyObject *map;
-            PyObject *keys = TOP();
+        inst(BUILD_CONST_KEY_MAP, (values[oparg], keys -- map)) {
             if (!PyTuple_CheckExact(keys) ||
                 PyTuple_GET_SIZE(keys) != (Py_ssize_t)oparg) {
                 _PyErr_SetString(tstate, PyExc_SystemError,
                                  "bad BUILD_CONST_KEY_MAP keys argument");
-                goto error;
+                goto error;  // Pop the keys and values.
             }
             map = _PyDict_FromItems(
                     &PyTuple_GET_ITEM(keys, 0), 1,
-                    &PEEK(oparg + 1), 1, oparg);
-            if (map == NULL) {
-                goto error;
-            }
-
-            Py_DECREF(POP());
-            while (oparg--) {
-                Py_DECREF(POP());
+                    values, 1, oparg);
+            Py_DECREF(keys);
+            for (int i = 0; i < oparg; i++) {
+                Py_DECREF(values[i]);
             }
-            PUSH(map);
+            ERROR_IF(map == NULL, error);
         }
 
         inst(DICT_UPDATE, (update --)) {
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index d433f9d0264edd..d5e591a8d6a246 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -1664,26 +1664,25 @@
         }
 
         TARGET(BUILD_CONST_KEY_MAP) {
+            PyObject *keys = PEEK(1);
+            PyObject **values = &PEEK(1 + oparg);
             PyObject *map;
-            PyObject *keys = TOP();
             if (!PyTuple_CheckExact(keys) ||
                 PyTuple_GET_SIZE(keys) != (Py_ssize_t)oparg) {
                 _PyErr_SetString(tstate, PyExc_SystemError,
                                  "bad BUILD_CONST_KEY_MAP keys argument");
-                goto error;
+                goto error;  // Pop the keys and values.
             }
             map = _PyDict_FromItems(
                     &PyTuple_GET_ITEM(keys, 0), 1,
-                    &PEEK(oparg + 1), 1, oparg);
-            if (map == NULL) {
-                goto error;
-            }
-
-            Py_DECREF(POP());
-            while (oparg--) {
-                Py_DECREF(POP());
+                    values, 1, oparg);
+            Py_DECREF(keys);
+            for (int i = 0; i < oparg; i++) {
+                Py_DECREF(values[i]);
             }
-            PUSH(map);
+            if (map == NULL) { STACK_SHRINK(oparg); goto pop_1_error; }
+            STACK_SHRINK(oparg);
+            POKE(1, map);
             DISPATCH();
         }
 

From 6cbabc7847ff870145e748b0f10b1eb387e5c2e2 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Fri, 13 Jan 2023 18:10:55 -0800
Subject: [PATCH 23/30] Add comment warning that RAISE_VARARGS needs to stay
 legacy

---
 Python/bytecodes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 50d9e2e5923cb3..b8f5e49ec89259 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -533,7 +533,7 @@ dummy_func(
             ERROR_IF(res == NULL, error);
         }
 
-        // stack effect: (__array[oparg] -- )
+        // This should remain a legacy instruction.
         inst(RAISE_VARARGS) {
             PyObject *cause = NULL, *exc = NULL;
             switch (oparg) {

From c7cfe9aeaf43f2443d47b0eb816b9b1d62bbc50d Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 17 Jan 2023 12:22:34 -0800
Subject: [PATCH 24/30] Look for 'oparg' in the whole instruction

---
 Python/opcode_metadata.h                |  8 ++++----
 Tools/cases_generator/generate_cases.py |  8 ++++----
 Tools/cases_generator/parser.py         | 19 +++++++++++++++----
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
index 5cb9881d797eaf..4891f07627ccba 100644
--- a/Python/opcode_metadata.h
+++ b/Python/opcode_metadata.h
@@ -45,8 +45,8 @@ static const struct {
     [BINARY_SUBSCR_TUPLE_INT] = { 2, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IXC000 },
     [BINARY_SUBSCR_DICT] = { 2, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IXC000 },
     [BINARY_SUBSCR_GETITEM] = { 2, 1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IXC000 },
-    [LIST_APPEND] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IX },
-    [SET_ADD] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IX },
+    [LIST_APPEND] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
+    [SET_ADD] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [STORE_SUBSCR] = { 3, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IXC },
     [STORE_SUBSCR_LIST_INT] = { 3, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IXC },
     [STORE_SUBSCR_DICT] = { 3, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IXC },
@@ -92,8 +92,8 @@ static const struct {
     [BUILD_STRING] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [BUILD_TUPLE] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [BUILD_LIST] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
-    [LIST_EXTEND] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IX },
-    [SET_UPDATE] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IX },
+    [LIST_EXTEND] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
+    [SET_UPDATE] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [BUILD_SET] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [BUILD_MAP] = { -1, -1, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [SETUP_ANNOTATIONS] = { 0, 0, DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IX },
diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index d0022fb2a49a35..079ba120a8a825 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -215,7 +215,7 @@ def __init__(self, inst: parser.InstDef):
             num_dummies = (num_regs // 2) * 2 + 1 - num_regs
             fmt = "I" + "B"*num_regs + "X"*num_dummies
         else:
-            if variable_used(inst.block, "oparg"):
+            if variable_used(inst, "oparg"):
                 fmt = "IB"
             else:
                 fmt = "IX"
@@ -965,9 +965,9 @@ def always_exits(lines: list[str]) -> bool:
     )
 
 
-def variable_used(block: parser.Block, name: str) -> bool:
-    """Determine whether a variable with a given name is used in a block."""
-    return any(token.kind == "IDENTIFIER" and token.text == name for token in block.tokens)
+def variable_used(node: parser.Node, name: str) -> bool:
+    """Determine whether a variable with a given name is used in a node."""
+    return any(token.kind == "IDENTIFIER" and token.text == name for token in node.tokens)
 
 
 def main():
diff --git a/Tools/cases_generator/parser.py b/Tools/cases_generator/parser.py
index 8cd4e8c194cf85..d2ed73caa50e2b 100644
--- a/Tools/cases_generator/parser.py
+++ b/Tools/cases_generator/parser.py
@@ -51,12 +51,23 @@ def to_text(self, dedent: int = 0) -> str:
         tokens = context.owner.tokens
         begin = context.begin
         end = context.end
-        return lx.to_text(tokens[begin:end], dedent)
+        return lx.to_text(self.tokens, dedent)
+
+    @property
+    def tokens(self) -> list[lx.Token]:
+        context = self.context
+        if not context:
+            return []
+        tokens = context.owner.tokens
+        begin = context.begin
+        end = context.end
+        return tokens[begin:end]
 
 
 @dataclass
 class Block(Node):
-    tokens: list[lx.Token]
+    # This just holds a context which has the list of tokens.
+    pass
 
 
 @dataclass
@@ -354,8 +365,8 @@ def members(self) -> list[str] | None:
 
     @contextual
     def block(self) -> Block:
-        tokens = self.c_blob()
-        return Block(tokens)
+        if self.c_blob():
+            return Block()
 
     def c_blob(self) -> list[lx.Token]:
         tokens: list[lx.Token] = []

From a1a4688ff687f2cfacbaec6f92b5aac6aa8cb600 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 17 Jan 2023 12:27:52 -0800
Subject: [PATCH 25/30] Add docstring for effect_size()

---
 Tools/cases_generator/generate_cases.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 079ba120a8a825..7730c2769f9347 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -49,6 +49,15 @@
 
 
 def effect_size(effect: StackEffect) -> tuple[int, str]:
+    """Return the 'size' impact of a stack effect.
+
+    Returns a tuple (numeric, symbolic) where:
+
+    - numeric is an int giving the statically analyzable size of the effect
+    - symbolic is a string representing a variable effect (e.g. 'oparg*2')
+
+    At most one of these will be non-zero / non-empty.
+    """
     if effect.size:
         return 0, effect.size
     else:

From 16a2d99d0356e581a1825c748b80a49842826231 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 17 Jan 2023 12:42:25 -0800
Subject: [PATCH 26/30] Parenthesize certain symbolic effects

Anything that's not 'oparg' or 'oparg*2' will be parenthesized.
---
 Python/generated_cases.c.h              |  8 ++++----
 Tools/cases_generator/generate_cases.py | 14 +++++++++++++-
 Tools/cases_generator/test_generator.py |  7 +++++++
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index d5e591a8d6a246..8b2737b8284f98 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -574,7 +574,7 @@
 
         TARGET(LIST_APPEND) {
             PyObject *v = PEEK(1);
-            PyObject *list = PEEK(2 + oparg-1);
+            PyObject *list = PEEK(2 + (oparg-1));
             if (_PyList_AppendTakeRef((PyListObject *)list, v) < 0) goto pop_1_error;
             STACK_SHRINK(1);
             PREDICT(JUMP_BACKWARD);
@@ -583,7 +583,7 @@
 
         TARGET(SET_ADD) {
             PyObject *v = PEEK(1);
-            PyObject *set = PEEK(2 + oparg-1);
+            PyObject *set = PEEK(2 + (oparg-1));
             int err = PySet_Add(set, v);
             Py_DECREF(v);
             if (err) goto pop_1_error;
@@ -1548,7 +1548,7 @@
 
         TARGET(LIST_EXTEND) {
             PyObject *iterable = PEEK(1);
-            PyObject *list = PEEK(2 + oparg-1);
+            PyObject *list = PEEK(2 + (oparg-1));
             PyObject *none_val = _PyList_Extend((PyListObject *)list, iterable);
             if (none_val == NULL) {
                 if (_PyErr_ExceptionMatches(tstate, PyExc_TypeError) &&
@@ -1570,7 +1570,7 @@
 
         TARGET(SET_UPDATE) {
             PyObject *iterable = PEEK(1);
-            PyObject *set = PEEK(2 + oparg-1);
+            PyObject *set = PEEK(2 + (oparg-1));
             int err = _PySet_Update(set, iterable);
             Py_DECREF(iterable);
             if (err < 0) goto pop_1_error;
diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 7730c2769f9347..841a8c0672af83 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -64,6 +64,18 @@ def effect_size(effect: StackEffect) -> tuple[int, str]:
         return 1, ""
 
 
+def maybe_parenthesize(sym: str) -> str:
+    """Add parentheses around a string if it contains an operator.
+
+    An exception is made for '*' which is common and harmless
+    in the context where the symbolic size is used.
+    """
+    if re.match(r"^[\s\w*]+$", sym):
+        return sym
+    else:
+        return f"({sym})"
+
+
 def list_effect_size(effects: list[StackEffect]) -> tuple[int, str]:
     numeric = 0
     symbolic: list[str] = []
@@ -71,7 +83,7 @@ def list_effect_size(effects: list[StackEffect]) -> tuple[int, str]:
         diff, sym = effect_size(effect)
         numeric += diff
         if sym:
-            symbolic.append(sym)
+            symbolic.append(maybe_parenthesize(sym))
     return numeric, " + ".join(symbolic)
 
 
diff --git a/Tools/cases_generator/test_generator.py b/Tools/cases_generator/test_generator.py
index dd7b77e268b9c2..5b9e8ae543094b 100644
--- a/Tools/cases_generator/test_generator.py
+++ b/Tools/cases_generator/test_generator.py
@@ -18,15 +18,22 @@ def test_effect_sizes():
         b := StackEffect("b", "", "oparg*4"),
         c := StackEffect("c", "", ""),
     ]
+    other_effects = [
+        p := StackEffect("p", "", "oparg<<1"),
+        q := StackEffect("q", "", ""),
+        r := StackEffect("r", "", ""),
+    ]
     assert generate_cases.effect_size(x) == (1, "")
     assert generate_cases.effect_size(y) == (0, "oparg")
     assert generate_cases.effect_size(z) == (0, "oparg*2")
 
     assert generate_cases.list_effect_size(input_effects) == (1, "oparg + oparg*2")
     assert generate_cases.list_effect_size(output_effects) == (2, "oparg*4")
+    assert generate_cases.list_effect_size(other_effects) == (2, "(oparg<<1)")
 
     assert generate_cases.string_effect_size(generate_cases.list_effect_size(input_effects)) == "1 + oparg + oparg*2"
     assert generate_cases.string_effect_size(generate_cases.list_effect_size(output_effects)) == "2 + oparg*4"
+    assert generate_cases.string_effect_size(generate_cases.list_effect_size(other_effects)) == "2 + (oparg<<1)"
 
 
 def run_cases_test(input: str, expected: str):

From 1ef085d9d0ac0f29e882a4eb4a81f1bcc1228b1e Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 17 Jan 2023 12:45:03 -0800
Subject: [PATCH 27/30] Fix typo in comment

---
 Tools/cases_generator/generate_cases.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 841a8c0672af83..053c1e1726241c 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -167,7 +167,7 @@ def assign(self, dst: StackEffect, src: StackEffect):
             # NOTE: MOVE_ITEMS() does not actually exist.
             # The only supported output array forms are:
             # - unused[...]
-            # - X[...] where X[...] matches an i99nput array form
+            # - X[...] where X[...] matches an input array exactly
             self.emit(f"MOVE_ITEMS({src.name}, {dst.name}, {src.size});")
         elif m := re.match(r"^REG\(oparg(\d+)\)$", dst.name):
             self.emit(f"Py_XSETREF({dst.name}, {cast}{src.name});")

From 1bf42ced2d1598761f8895cdf2efeaa8ac0fbed9 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 17 Jan 2023 12:48:01 -0800
Subject: [PATCH 28/30] Swap args of imaginary MOVE_ITEMS() macro

---
 Tools/cases_generator/generate_cases.py | 2 +-
 Tools/cases_generator/test_generator.py | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 053c1e1726241c..1e9c4f9a6aa6b9 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -168,7 +168,7 @@ def assign(self, dst: StackEffect, src: StackEffect):
             # The only supported output array forms are:
             # - unused[...]
             # - X[...] where X[...] matches an input array exactly
-            self.emit(f"MOVE_ITEMS({src.name}, {dst.name}, {src.size});")
+            self.emit(f"MOVE_ITEMS({dst.name}, {src.name}, {src.size});")
         elif m := re.match(r"^REG\(oparg(\d+)\)$", dst.name):
             self.emit(f"Py_XSETREF({dst.name}, {cast}{src.name});")
         else:
diff --git a/Tools/cases_generator/test_generator.py b/Tools/cases_generator/test_generator.py
index 5b9e8ae543094b..ae0c1e2f97c35e 100644
--- a/Tools/cases_generator/test_generator.py
+++ b/Tools/cases_generator/test_generator.py
@@ -391,7 +391,7 @@ def test_array_output():
             STACK_GROW(2);
             STACK_GROW(oparg*3);
             POKE(1, above);
-            MOVE_ITEMS(values, &PEEK(1 + oparg*3), oparg*3);
+            MOVE_ITEMS(&PEEK(1 + oparg*3), values, oparg*3);
             POKE(2 + oparg*3, below);
             DISPATCH();
         }
@@ -411,7 +411,7 @@ def test_array_input_output():
             PyObject *above;
             spam();
             POKE(1, above);
-            MOVE_ITEMS(values, &PEEK(1 + oparg), oparg);
+            MOVE_ITEMS(&PEEK(1 + oparg), values, oparg);
             DISPATCH();
         }
     """

From c2be1ab0a2c2b9e62e5865837a6acf1fbe787318 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 17 Jan 2023 13:08:48 -0800
Subject: [PATCH 29/30] Tune for loops

---
 Tools/cases_generator/generate_cases.py | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/Tools/cases_generator/generate_cases.py b/Tools/cases_generator/generate_cases.py
index 1e9c4f9a6aa6b9..59e249930b45df 100644
--- a/Tools/cases_generator/generate_cases.py
+++ b/Tools/cases_generator/generate_cases.py
@@ -275,8 +275,7 @@ def write(self, out: Formatter) -> None:
         if not self.register:
             # Write input stack effect variable declarations and initializations
             ieffects = list(reversed(self.input_effects))
-            for i in range(len(ieffects)):
-                ieffect = ieffects[i]
+            for i, ieffect in enumerate(ieffects):
                 isize = string_effect_size(list_effect_size(ieffects[:i+1]))
                 if ieffect.size:
                     src = StackEffect(f"&PEEK({isize})", "PyObject **")
@@ -309,8 +308,7 @@ def write(self, out: Formatter) -> None:
 
             # Write output stack effect assignments
             oeffects = list(reversed(self.output_effects))
-            for i in range(len(oeffects)):
-                oeffect = oeffects[i]
+            for i, oeffect in enumerate(oeffects):
                 if oeffect.name in self.unmoved_names:
                     continue
                 osize = string_effect_size(list_effect_size(oeffects[:i+1]))

From c7edea2268b2069abdd647362ab97839e52ed6d4 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 17 Jan 2023 13:16:54 -0800
Subject: [PATCH 30/30] Disallow empty dimension

---
 Tools/cases_generator/parser.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Tools/cases_generator/parser.py b/Tools/cases_generator/parser.py
index d2ed73caa50e2b..c2cebe96ccd6be 100644
--- a/Tools/cases_generator/parser.py
+++ b/Tools/cases_generator/parser.py
@@ -261,6 +261,8 @@ def dimension(self) -> Dimension | None:
         while (tkn := self.peek()) and tkn.kind != lx.RBRACKET:
             tokens.append(tkn)
             self.next()
+        if not tokens:
+            return None
         return Dimension(lx.to_text(tokens).strip())
 
     @contextual