Landing: afa9dd376907
Project / Subsystem
gcc / scheduler
Date
2026-09-14
Author
xiezhiheng
Commit
afa9dd3769077c50180865f53bf2ff8abb0a2f97
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- scheduler
- patch_id
- —
- commit_hash
- afa9dd3769077c50180865f53bf2ff8abb0a2f97
- source_type
- github
- headline
- sched: Cap max_lookahead_tries to prevent overflow
- tldr
- Prevents scheduler overflow on modern cores by capping `max_lookahead_tries`.
- author
- xiezhiheng
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • scheduler
- • AArch64
- • overflow
- • optimization
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-14T00:00:00.000Z
The issue rate on modern CPU cores has been increasing, leading to a value of 10 in the AArch64 backend’s max_issue calculation. This caused an integer overflow when calculating max_lookahead_tries. This commit caps max_lookahead_tries to prevent this overflow, ensuring the scheduler operates correctly. The change is a small but crucial fix for handling high issue rates on contemporary hardware.