Landing: 7decbb57670c
Project / Subsystem
gcc / gcc/match
Date
2026-07-30
Author
Reshma Roy
Commit
7decbb57670c3c0f6136be00456fe9c8a41f7aed
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc/match
- patch_id
- —
- commit_hash
- 7decbb57670c3c0f6136be00456fe9c8a41f7aed
- source_type
- github
- headline
- Fixes incorrect POPCOUNT pattern identification.
- tldr
- Corrects a pattern matcher to accurately identify the POPCOUNT intrinsic, preventing incorrect optimizations.
- author
- Reshma Roy
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • pattern matching
- • intrinsics
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-30T00:00:00.000Z
This commit corrects a bug in GCC’s pattern matching for the POPCOUNT intrinsic. A previously introduced 32-bit matcher incorrectly identified patterns, accepting any mask due to a flawed predicate. The fix ensures that only the intended Hacker’s Delight popcount idiom is folded into the IFN_POPCOUNT intrinsic by adding a necessary constant check.