Landing: 1de4393ddec6
Project / Subsystem
gcc / s390
Date
2026-10-06
Author
Stefan Schulze Frielinghaus
Commit
1de4393ddec6ce2980184f32b0fd428c54d82a20
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- s390
- patch_id
- —
- commit_hash
- 1de4393ddec6ce2980184f32b0fd428c54d82a20
- source_type
- github
- headline
- s390: Fix bswap:HI reg-reg splitter to avoid ICE
- tldr
- Fixes a compiler ICE on s390 by ensuring the bswap:HI reg-reg splitter only runs after register allocation.
- author
- Stefan Schulze Frielinghaus
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • s390
- • compiler bug
- • ICE
- • register allocation
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-10-06T00:00:00.000Z
A compiler internal error (ICE) on s390 occurred because the bswap:HI reg-reg splitter was incorrectly firing before register allocation. This led to invalid subregister operations that simplified_gen_subreg could not handle, resulting in NULL_RTX and a crash. The fix ensures the splitter runs only after register allocation, when it operates on hard registers and avoids paradoxical subreg issues, while also adding a safety check for NULL_RTX.