Landing: 1df63c7f3a3f
Project / Subsystem
gcc / i386
Date
2026-08-26
Author
Sun, Qin
Commit
1df63c7f3a3f9c52669c11d289abc0238e909813
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- i386
- patch_id
- —
- commit_hash
- 1df63c7f3a3f9c52669c11d289abc0238e909813
- source_type
- github
- headline
- i386: Fix vec_concatv2df condition to match its constraints
- tldr
- i386: Corrects a miss-optimization in vec_concatv2df by refining its condition to prevent unnecessary reloads.
- author
- Sun, Qin
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • x86
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-26T00:00:00.000Z
This patch corrects a miss-optimization in the i386 vec_concatv2df instruction pattern. The previous condition incorrectly allowed memory operands in certain cases, forcing a reload and potentially an extra instruction. By restricting the condition to only accept CONST0_RTX as operand 2 when operand 1 is a memory operand, the compiler avoids this issue and generates more efficient code, as demonstrated in the provided example.