Landing: af981ba6b6df
Project / Subsystem
gcc / risc-v
Date
2026-09-04
Author
Jakub Jelinek
Commit
af981ba6b6dfb1a7e15e4472318535ab7d866893
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- risc-v
- patch_id
- —
- commit_hash
- af981ba6b6dfb1a7e15e4472318535ab7d866893
- source_type
- github
- headline
- RISC-V: Improve __builtin_bitreverse code generation with ZBKB extension.
- tldr
- RISC-V __builtin_bitreverse functions now use more efficient instructions when the ZBKB extension is enabled.
- author
- Jakub Jelinek
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • risc-v
- • optimization
- • builtin
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-04T00:00:00.000Z
GCC improves code generation for __builtin_bitreverse{8,16,32,64} on RISC-V when the ZBKB extension is enabled. It now utilizes specific brev8 or rev8 instructions for better performance. The change also adjusts the condition for using the bswaphi2 instruction to include the ZBKB extension.