Landing: 238a3c104226
Project / Subsystem
gcc / aarch64
Date
2026-09-10
Author
Dominic P
Commit
238a3c1042262cb5f4107fb3a90c679e00d9d0c8
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- aarch64
- patch_id
- —
- commit_hash
- 238a3c1042262cb5f4107fb3a90c679e00d9d0c8
- source_type
- github
- headline
- AArch64 supports rounding narrowing shifts at source width.
- tldr
- Enables AArch64 to match rounding narrowing shift instructions written at the source data width.
- author
- Dominic P
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • aarch64
- • optimization
- • SIMD
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-10T00:00:00.000Z
This change introduces new AArch64 instruction patterns to match rounding narrowing shifts (RSHRN) when the operation is expressed at the source data width, rather than requiring a wider intermediate representation. This improves code generation for common narrowing operations, reducing instruction counts in areas like video encoding and media processing.