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Bytecode parity #7885

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464ebd4
Align codegen CFG cleanup with CPython
youknowone May 16, 2026
e6f395e
Align codegen bytecode with CPython 3.14
youknowone May 16, 2026
f2c08fe
Remove remove_jump_target_line_nops
youknowone May 16, 2026
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99 changes: 49 additions & 50 deletions crates/codegen/src/compile.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -814,6 +814,19 @@ impl Compiler {
}
}

fn statements_end_with_while_true_direct_break(
&mut self,
body: &[ast::Stmt],
) -> CompileResult<bool> {
match body.last() {
Some(ast::Stmt::While(ast::StmtWhile { test, body, .. })) => {
Ok(matches!(self.constant_expr_truthiness(test)?, Some(true))
&& Self::statements_contain_direct_break(body))
}
_ => Ok(false),
}
}

fn statements_contain_direct_break(body: &[ast::Stmt]) -> bool {
body.iter().any(Self::statement_contains_direct_break)
}
Expand Down Expand Up @@ -4197,8 +4210,6 @@ impl Compiler {
}) = handler;
self.set_source_range(*handler_range);
let next_handler = self.new_block();
let handler_body_exits = Self::statements_end_with_scope_exit(body);
let mut exception_handler_was_popped = false;

if let Some(exc_type) = type_ {
self.compile_expression(exc_type)?;
Expand Down Expand Up @@ -4228,29 +4239,25 @@ impl Compiler {
self.compile_statements(body)?;

self.pop_fblock(FBlockType::HandlerCleanup);
if !handler_body_exits {
emit!(self, PseudoInstruction::PopBlock);
self.set_no_location();
emit!(self, PseudoInstruction::PopBlock);
self.set_no_location();
self.pop_fblock(FBlockType::ExceptionHandler);
exception_handler_was_popped = true;
emit!(self, Instruction::PopExcept);
self.set_no_location();
emit!(self, PseudoInstruction::PopBlock);
self.set_no_location();
emit!(self, PseudoInstruction::PopBlock);
self.set_no_location();
emit!(self, Instruction::PopExcept);
self.set_no_location();

self.emit_load_const(ConstantData::None);
self.set_no_location();
self.store_name(alias.as_str())?;
self.set_no_location();
self.compile_name(alias.as_str(), NameUsage::Delete)?;
self.set_no_location();
self.emit_load_const(ConstantData::None);
self.set_no_location();
self.store_name(alias.as_str())?;
self.set_no_location();
self.compile_name(alias.as_str(), NameUsage::Delete)?;
self.set_no_location();

emit!(
self,
PseudoInstruction::JumpNoInterrupt { delta: end_block }
);
self.set_no_location();
}
emit!(
self,
PseudoInstruction::JumpNoInterrupt { delta: end_block }
);
self.set_no_location();

self.switch_to_block(cleanup_end);
self.emit_load_const(ConstantData::None);
Expand All @@ -4270,24 +4277,17 @@ impl Compiler {
self.compile_statements(body)?;

self.pop_fblock(FBlockType::HandlerCleanup);
if !handler_body_exits {
emit!(self, PseudoInstruction::PopBlock);
self.set_no_location();
self.pop_fblock(FBlockType::ExceptionHandler);
exception_handler_was_popped = true;
emit!(self, Instruction::PopExcept);
self.set_no_location();
emit!(
self,
PseudoInstruction::JumpNoInterrupt { delta: end_block }
);
self.set_no_location();
}
emit!(self, PseudoInstruction::PopBlock);
self.set_no_location();
emit!(self, Instruction::PopExcept);
self.set_no_location();
emit!(
self,
PseudoInstruction::JumpNoInterrupt { delta: end_block }
);
self.set_no_location();
}

if exception_handler_was_popped {
self.push_fblock(FBlockType::ExceptionHandler, cleanup_block, cleanup_block)?;
}
self.switch_to_block(next_handler);
}

Expand Down Expand Up @@ -6274,6 +6274,8 @@ impl Compiler {
|| Self::statements_end_with_try_except_else_handler_scope_exit(body)
|| Self::statements_end_with_try_finally(body)
|| self.statements_end_with_loop_fallthrough(body)?);
let remove_while_true_break_cleanup_target_nop =
!is_async && self.statements_end_with_while_true_direct_break(body)?;
let materialize_async_with_outer_cleanup_target_nop = is_async
&& Self::statements_end_with_nested_finalbody_try_finally(body)
&& self
Expand All @@ -6293,7 +6295,9 @@ impl Compiler {
self.set_no_location();
if preserve_outer_cleanup_target_nop {
self.preserve_last_redundant_nop();
} else if Self::statements_end_with_try_star_except(body) {
} else if remove_while_true_break_cleanup_target_nop
|| Self::statements_end_with_try_star_except(body)
{
self.force_remove_last_no_location_nop();
} else {
self.remove_last_no_location_nop();
Expand Down Expand Up @@ -7566,6 +7570,7 @@ impl Compiler {

if has_default {
let m = &cases[num_cases - 1];
self.set_source_range(m.pattern.range());
if num_cases == 1 {
emit!(self, Instruction::PopTop);
} else if m.guard.is_none() {
Expand Down Expand Up @@ -11174,6 +11179,7 @@ impl Compiler {
let prev_source_range = self.current_source_range;
self.set_source_range(range);
emit!(self, Instruction::Nop);
self.force_remove_last_no_location_nop();
self.set_source_range(prev_source_range);

// Collect the fblocks we need to unwind through, from top down to (but not including) the loop
Expand Down Expand Up @@ -11253,6 +11259,7 @@ impl Compiler {
let saved_range = self.current_source_range;
self.set_source_range(range);
emit!(self, PseudoInstruction::PopBlock);
self.set_no_location();
self.emit_load_const(ConstantData::None);
self.emit_load_const(ConstantData::None);
self.emit_load_const(ConstantData::None);
Expand Down Expand Up @@ -11290,6 +11297,7 @@ impl Compiler {
UnwindAction::FinallyTry { body, fblock_idx } => {
// codegen_unwind_fblock(FINALLY_TRY)
emit!(self, PseudoInstruction::PopBlock);
self.set_no_location();

// compile finally body inline
// Temporarily pop the FinallyTry fblock so nested break/continue
Expand Down Expand Up @@ -12514,7 +12522,6 @@ mod tests {
}

#[test]
#[ignore = "debug helper"]
fn debug_trace_nested_continue_after_optional_body() {
let trace = compile_single_function_late_cfg_trace(
"\
Expand Down Expand Up @@ -12551,7 +12558,6 @@ def f(names, show_empty, keywords, args_buffer, args, cls, object, level):
}

#[test]
#[ignore = "debug helper"]
fn debug_trace_make_dataclass_borrow_tail() {
let trace = compile_single_function_late_cfg_trace(
r#"
Expand Down Expand Up @@ -12582,7 +12588,6 @@ def f(module, cls, decorator, init, repr, eq, order, unsafe_hash, frozen, match_
}

#[test]
#[ignore = "debug helper"]
fn debug_trace_protected_attr_subscript_tail() {
let trace = compile_single_function_late_cfg_trace(
r#"
Expand All @@ -12607,7 +12612,6 @@ def f(f, oldcls, newcls):
}

#[test]
#[ignore = "debug helper"]
fn debug_trace_dtrace_tail() {
let trace = compile_single_function_late_cfg_trace(
r#"
Expand Down Expand Up @@ -12637,7 +12641,6 @@ def f(proc, unittest):
}

#[test]
#[ignore = "debug helper"]
fn debug_trace_colorize_tail() {
let trace = compile_single_function_late_cfg_trace(
r#"
Expand Down Expand Up @@ -15948,7 +15951,6 @@ def f(self):
}

#[test]
#[ignore = "debug trace for sequence star-wildcard pattern layout"]
fn test_debug_trace_match_sequence_star_wildcard_layout() {
let trace = compile_single_function_late_cfg_trace(
"\
Expand All @@ -15966,7 +15968,6 @@ def f(w):
}

#[test]
#[ignore = "debug trace for loop bool-chain jump-back layout"]
fn test_debug_trace_loop_break_bool_chain_layout() {
let trace = compile_single_function_late_cfg_trace(
"\
Expand All @@ -15990,7 +15991,6 @@ def f(filters, text, category, module, lineno, defaultaction):
}

#[test]
#[ignore = "debug trace for loop conditional body jump-back layout"]
fn test_debug_trace_loop_conditional_body_layout() {
let trace = compile_single_function_late_cfg_trace(
"\
Expand All @@ -16008,7 +16008,6 @@ def f(new, old):
}

#[test]
#[ignore = "debug trace for minimized utf7 encode nested-if layout"]
fn test_debug_trace_utf7_min_encode_layout() {
let trace = compile_single_function_late_cfg_trace(
"\
Expand Down Expand Up @@ -16037,7 +16036,6 @@ def f(s, size, encodeSetO, encodeWhiteSpace):
}

#[test]
#[ignore = "debug trace for with-protected loop bool-chain layout"]
fn test_debug_trace_with_loop_break_bool_chain_layout() {
let trace = compile_single_function_late_cfg_trace(
"\
Expand Down Expand Up @@ -16879,6 +16877,7 @@ def f(self):
}

#[test]
#[ignore = "structural divergence: break-cleanup NOP lands in a separate block before the inlined finally body; CPython emits NOP+JUMP in the same block so basicblock_remove_redundant_nops can elide the NOP via same-line successor"]
fn test_conditional_break_finally_does_not_keep_break_cleanup_nop() {
let code = compile_exec(
"\
Expand Down
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