Landing: 10c43486134d
Project / Subsystem
gcc / aarch64
Date
2026-07-29
Author
Christopher Bazley
Commit
10c43486134d6a64e941fc758f2aa20008b43190
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- aarch64
- patch_id
- —
- commit_hash
- 10c43486134d6a64e941fc758f2aa20008b43190
- source_type
- github
- headline
- AArch64: Improve vectorizer's costing of truncated stores.
- tldr
- Vectorizer now correctly costs truncated stores on AArch64, preventing incorrect vectorization of scalar code.
- author
- Christopher Bazley
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • aarch64
- • vectorization
- • performance
- • compiler optimization
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-29T00:00:00.000Z
This commit enhances the AArch64 vectorizer’s accuracy by improving the costing of truncated stores. Previously, the vectorizer overestimated costs for scalar assignments that were effectively free as part of a store operation, potentially leading to incorrect vectorization. A new function, vect_is_truncating_store, is introduced to identify these cases, ensuring that code with truncating stores is not mis-vectorized.