Landing: 4fe2072d5d16
Project / Subsystem
gcc / tree-optimization
Date
2026-08-17
Author
Richard Biener
Commit
4fe2072d5d16ce26112d8035e627d47809aaa6c2
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- tree-optimization
- patch_id
- —
- commit_hash
- 4fe2072d5d16ce26112d8035e627d47809aaa6c2
- source_type
- github
- headline
- Allow backward threading to loop exit
- tldr
- Loop optimization can now thread backward through loop headers to exit, enabling better peeling of non-iterating loops.
- author
- Richard Biener
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • compiler
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-17T00:00:00.000Z
This change enhances the backward threader in GCC’s tree-ssa optimization passes. It allows threading to pass through loop headers when exiting a loop, which helps in fully peeling loops that do not iterate. Care has been taken to prevent random loop peeling, with specific measures and new test cases added to ensure correctness.