Landing: bab20a370641
Project / Subsystem
gcc / gcc/vectorization
Date
2026-04-28
Author
Richard Biener
Commit
bab20a370641484fffa5ac5bb30b7d19f5d3fe92
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc/vectorization
- patch_id
- —
- commit_hash
- bab20a370641484fffa5ac5bb30b7d19f5d3fe92
- source_type
- github
- headline
- Improve x86 epilogue loop selection with cost comparison.
- tldr
- The compiler now prefers existing epilogues unless a new candidate offers optimal vectorization, resolving a test failure.
- author
- Richard Biener
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • gcc
- • vectorization
- • x86
- • optimization
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-04-28T00:00:00.000Z
This commit resolves a failure in gcc.target/i386/vect-epilogues-3.c when --param ix86-vect-compare-costs=1 is specified. The change modifies the better_epilogue_loop_than_p function to favor the existing epilogue when the target requests multiple epilogues, unless the new candidate uses a vectorization factor of one. This prevents regressions in gcc.dg/vect/costmodel/x86_64/costmodel-pr122573.c.