Landing: 1dc037ec4216
Project / Subsystem
gcc / aarch64
Date
2026-09-10
Author
Dominic P
Commit
1dc037ec42169fe28715dc3fa8181506046dab1c
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- aarch64
- patch_id
- —
- commit_hash
- 1dc037ec42169fe28715dc3fa8181506046dab1c
- source_type
- github
- headline
- Improve AArch64 rounding shift-right pair reachability.
- tldr
- Makes AArch64 rounding shift-right instructions more accessible to generic code.
- author
- Dominic P
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • aarch64
- • optimization
- • vectorization
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-10T00:00:00.000Z
AArch64’s rounding shift-right instructions were previously only reachable by their own specific expanders, preventing general code and the optimizer from utilizing them effectively. This change modifies these instructions to accept shift amounts as vectors, making them compatible with generic code and improving optimization opportunities, such as simplifying sequences involving addition and shifts.