Landing: 0a1b2250a962
Project / Subsystem
gcc / s390
Date
2026-09-29
Author
Stefan Schulze Frielinghaus
Commit
0a1b2250a962e7a500768e98363ec4dc0179155a
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- s390
- patch_id
- —
- commit_hash
- 0a1b2250a962e7a500768e98363ec4dc0179155a
- source_type
- github
- headline
- Improve GCC build time on s390
- tldr
- Optimized scheduler description processing to reduce GCC build times on s390.
- author
- Stefan Schulze Frielinghaus
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • s390
- • build time
- • optimization
- • compiler
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-29T00:00:00.000Z
This commit significantly reduces GCC’s build time on the s390 architecture by optimizing how scheduler descriptions are processed, particularly impacting partial rebuilds. The bottleneck was identified in genattrtab, where complex attribute definitions led to massive intermediate expression (RTX) structures. The changes refactor the construction of these expressions, moving from a right-biased insertion that leads to O(n^2) complexity to a more efficient method that avoids quadratic blowup in expression simplification and insertion.