Module `opshin.optimize.optimize_remove_unreachable`

Expand source code

from ..typed_util import ScopedSequenceNodeTransformer

"""
Removes statements that are unreachable because a previous statement in the same
sequence is known not to fall through.
"""


class OptimizeRemoveUnreachable(ScopedSequenceNodeTransformer):
    step = "Removing unreachable statements"

    def visit_sequence(self, statements):
        visited = []
        for stmt in statements:
            if stmt is None:
                continue
            stmt_cp = self.visit(stmt)
            if stmt_cp is None:
                continue
            visited.append(stmt_cp)
            if not getattr(stmt_cp, "can_fall_through", True):
                break
        return visited

Classes

class OptimizeRemoveUnreachable

Rewrite nested statement sequences while preserving the surrounding node.

Expand source code

class OptimizeRemoveUnreachable(ScopedSequenceNodeTransformer):
    step = "Removing unreachable statements"

    def visit_sequence(self, statements):
        visited = []
        for stmt in statements:
            if stmt is None:
                continue
            stmt_cp = self.visit(stmt)
            if stmt_cp is None:
                continue
            visited.append(stmt_cp)
            if not getattr(stmt_cp, "can_fall_through", True):
                break
        return visited

Ancestors

Class variables

var step: Inherited from: ScopedSequenceNodeTransformer.step

The type of the None singleton.

Methods

def visit(self, node)

Inherited from: ScopedSequenceNodeTransformer.visit

Visit a node.

def visit_sequence(self, statements)

Expand source code

def visit_sequence(self, statements):
    visited = []
    for stmt in statements:
        if stmt is None:
            continue
        stmt_cp = self.visit(stmt)
        if stmt_cp is None:
            continue
        visited.append(stmt_cp)
        if not getattr(stmt_cp, "can_fall_through", True):
            break
    return visited