Landing: 1bdc9e13987f
Project / Subsystem
gcc / gcc/match.pd
Date
2026-05-22
Author
Jakub Jelinek
Commit
1bdc9e13987fc7451a4f11cfdf8b6dfb827cf9f5
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc/match.pd
- patch_id
- —
- commit_hash
- 1bdc9e13987fc7451a4f11cfdf8b6dfb827cf9f5
- source_type
- github
- headline
- Match.pd now handles BUILT_IN_BITREVERSE8 like the other bitreverses.
- tldr
- GCC's pattern-matching pass now recognises `__builtin_bitreverse8` when optimising bit-reversal operations.
- author
- Jakub Jelinek
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • gcc
- • optimization
- • bit manipulation
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-05-22T00:00:00.000Z
GCC’s pattern matching pass (match.pd) missed BUILT_IN_BITREVERSE8 when optimizing bit-reversal operations; this commit adds it to the BITREVERSE operator list. The change comes with additional test cases for __builtin_bitreverse{8,16,64,128}.