Landing: d8f1bd8c34a2
Project / Subsystem
gcc / tree-optimization
Date
2026-08-31
Author
Richard Biener
Commit
d8f1bd8c34a289de0810178d897cb246ce2033cf
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- tree-optimization
- patch_id
- —
- commit_hash
- d8f1bd8c34a289de0810178d897cb246ce2033cf
- source_type
- github
- headline
- Fixes incorrect lane calculation for vector reductions.
- tldr
- Corrects lane calculation in vectorizer to fix wrong code for reduction operations.
- author
- Richard Biener
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • vectorization
- • bugfix
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-31T00:00:00.000Z
This commit fixes an issue in the vectorizer where the calculation of excess lanes for lane-reducing reductions was incorrect. The poly computation for the number of copies for an invariant value is now ensured to be constant, resolving wrong code in vectorized reduction operations. A new test case is added to verify the fix.