Class Branch

mypyc/ir/ops.py:427–490

Branch based on a value. If op is BOOL, branch based on a bit/bool value: if [not] r1 goto L1 else goto L2 If op is IS_ERROR, branch based on whether there is an error value: if [not] is_error(r1) goto L1 else goto L2

@final
class Branch(ControlOp):
    """Branch based on a value.

    If op is BOOL, branch based on a bit/bool value:
       if [not] r1 goto L1 else goto L2

    If op is IS_ERROR, branch based on whether there is an error value:
       if [not] is_error(r1) goto L1 else goto L2
    """

    # Branch ops never raise an exception.
    error_kind = ERR_NEVER

    BOOL: Final = 100
    IS_ERROR: Final = 101

    def __init__(
        self,
        value: Value,
        true_label: BasicBlock,
        false_label: BasicBlock,
        op: int,
        line: int = -1,
        *,
        rare: bool = False,
    ) -> None:
        super().__init__(line)
        # Target value being checked
        self.value = value
        # Branch here if the condition is true
        self.true = true_label
        # Branch here if the condition is false
        self.false = false_label
        # Branch.BOOL (boolean check) or Branch.IS_ERROR (error value check)
        self.op = op
        # If True, the condition is negated
        self.negated = False
        # If not None, the true label should generate a traceback entry (func name, line number)
        self.traceback_entry: tuple[str, int] | None = None
        # If True, we expect to usually take the false branch (for optimization purposes);
        # this is implicitly treated as true if there is a traceback entry
        self.rare = rare

    def targets(self) -> Sequence[BasicBlock]:
        return (self.true, self.false)

    def set_target(self, i: int, new: BasicBlock) -> None:
        assert i == 0 or i == 1
        if i == 0:
            self.true = new
        else:
            self.false = new

    def sources(self) -> list[Value]:
        return [self.value]

    def set_sources(self, new: list[Value]) -> None:
        (self.value,) = new