Landing: 301afaab5b8e
Project / Subsystem
gcc / ifcvt
Date
2026-08-23
Author
Kyrylo Tkachov
Commit
301afaab5b8eafd3d24234fbc266be05590e1acf
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- ifcvt
- patch_id
- —
- commit_hash
- 301afaab5b8eafd3d24234fbc266be05590e1acf
- source_type
- github
- headline
- ifcvt: Handle disjoint live-outs in diamond conversions for ARM
- tldr
- The ifcvt pass now correctly handles conditional diamond conversions on ARM where arms update distinct live-out variables.
- author
- Kyrylo Tkachov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • arm
- • optimization
- • if-conversion
- • compiler pass
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-23T00:00:00.000Z
The ifcvt (if-conversion) pass has been improved to handle conditional diamond conversions, particularly on ARM, when the two branches of the diamond update different sets of live-out variables. Previously, it required overlapping live-outs, forcing the use of temporary variables for values only defined in one arm. This change allows for more flexible and efficient conversion by correctly managing disjoint live-outs and enabling one-set arms, improving code generation for conditional constructs.