Landing: fe724b27ce6d
Project / Subsystem
gcc / aarch64
Date
2026-07-21
Author
Tamar Christina
Commit
fe724b27ce6dadb82d0a51b8232bca13405d7abc
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- aarch64
- patch_id
- —
- commit_hash
- fe724b27ce6dadb82d0a51b8232bca13405d7abc
- source_type
- github
- headline
- Fold WHILE_ULT to ptrue for AArch64 SVE.
- tldr
- Optimize ARM SVE loops by folding WHILE_ULT into ptrue.
- author
- Tamar Christina
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • aarch64
- • sve
- • optimization
- • vectorization
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-21T00:00:00.000Z
This optimization for AArch64 with Scalable Vector Extension (SVE) targets the WHILE_ULT instruction, commonly used in loop pre-headers. Due to architectural guarantees on minimum and maximum vector lengths, the predicate generated by WHILE_ULT is always an all-lanes-active predicate (ptrue). This change replaces WHILE_ULT with ptrue where applicable, reducing the overhead of entering loops and improving performance.