Landing: ddacdb8b37ce
Project / Subsystem
gcc / gcc
Date
2026-06-08
Author
Richard Sandiford
Commit
ddacdb8b37ce268cac26e594e8f84b530b4f85b4
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc
- patch_id
- —
- commit_hash
- ddacdb8b37ce268cac26e594e8f84b530b4f85b4
- source_type
- github
- headline
- Simplifies vec_duplicates of vec_duplicates
- tldr
- This commit simplifies nested `vec_duplicate` operations in GCC's RTL, folding them into a single `vec_duplicate` to improve optimization.
- author
- Richard Sandiford
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • rtl
- • aarch64
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-06-08T00:00:00.000Z
GCC’s RTL simplifier now optimizes expressions that involve duplicating replicated vectors. Previously, a vec_duplicate of another vec_duplicate could occur unnecessarily. This change modifies simplify_context::simplify_unary_operation_1 to detect and fold these nested operations into a single vec_duplicate, improving the efficiency of the intermediate representation and potentially affecting downstream optimizations. This was primarily observed and fixed in AArch64 SVE specific patterns.