Changelog — v2.0.1

Released: 2026-10-07

A front-end timing fix: decode no longer refetches a path fetch already took, which made IPC depend on unrelated parameters.

Fixed

• Decode refetched the path fetch had already taken whenever it found a branch the BTB missed, predicted it not taken, and fetch had predicted a younger branch: it undid the younger predictions, which were made without the branch in the histories, and redirected fetch to remake them. A never-taken branch, which never enters the BTB, paid this every loop iteration, so how often it happened depended on front-end timing and moved IPC with unrelated parameters (#143). Decode now redoes those predictions in program order as it reaches them and redirects only when the path changes. bp.decode_redirects falls by up to 99% and the affected programs take up to 10% fewer cycles; mispredictions are unchanged.