Landing: 3f6fb81133df
Project / Subsystem
gcc / ifcvt
Date
2026-09-28
Author
Stian Halseth
Commit
3f6fb81133dfa2b8f843b328fd6b697534e7b3fe
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- ifcvt
- patch_id
- —
- commit_hash
- 3f6fb81133dfa2b8f843b328fd6b697534e7b3fe
- source_type
- github
- headline
- ifcvt: Avoid clobbering live condition-code register
- tldr
- Fixes miscompilations on SPARC by preventing if-conversion from overwriting live condition codes.
- author
- Stian Halseth
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • ifcvt
- • sparc
- • compiler bug
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-28T00:00:00.000Z
The if-conversion pass’s find_cond_trap function has been updated to prevent it from overwriting a live condition-code register. Previously, on SPARC, this could lead to incorrect program behavior when a condition code set earlier in the code was needed by a later branch, causing miscompilations, particularly for switch statements with unreachable default cases. The fix reuses an existing check (noce_clobbers_live_cc_p) to ensure condition codes are not clobbered, resolving issues on SPARC64.