Landing: 6cda72b8bd64
Project / Subsystem
gcc / range
Date
2026-08-13
Author
Aldy Hernandez
Commit
6cda72b8bd646c32a691ae1424387da259f61edc
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- range
- patch_id
- —
- commit_hash
- 6cda72b8bd646c32a691ae1424387da259f61edc
- source_type
- github
- headline
- Range analysis handles abnormal PHIs
- tldr
- GCC's range analysis no longer avoids SSA names in abnormal PHIs, allowing for more comprehensive analysis.
- author
- Aldy Hernandez
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • range analysis
- • gcc
- • optimization
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-13T00:00:00.000Z
GCC’s range analysis has been updated to no longer restrict itself from analyzing SSA names that occur within abnormal PHI nodes. Previously, this restriction was in place due to a misunderstanding of the ‘abnormal’ marker, which pertains to transformation constraints rather than analysis limitations. The range analysis can now correctly determine value ranges even when PHIs are involved in abnormal control flow paths, as the core semantics of PHI and copy operations still hold. This change aims to improve the accuracy and completeness of range analysis.