Landing: ce285dde2110
Project / Subsystem
gcc / libstdc++
Date
2026-07-28
Author
Tomasz Kamiński
Commit
ce285dde2110f453fdbbd89fbb2f85a4d039705d
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- libstdc++
- patch_id
- —
- commit_hash
- ce285dde2110f453fdbbd89fbb2f85a4d039705d
- source_type
- github
- headline
- Timezone database loading: calculate DST save adjustment upfront
- tldr
- Improves performance of timezone lookups after the first call by pre-calculating DST offsets.
- author
- Tomasz Kamiński
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • performance
- • timezone
- • c++
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-28T00:00:00.000Z
This change optimizes timezone handling in libstdc++ by calculating daylight saving time (DST) save adjustments when the timezone database is loaded, rather than on-demand. Previously, calculating these adjustments could incur a performance cost on subsequent lookups, even with caching. By performing the calculation during the initial database load, subsequent calls to retrieve time zone information are faster, though the initial load time increases slightly.