Landing: 8747b25bcd96

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Project / Subsystem

gcc / i386

Date

2026-09-10

Author

Uros Bizjak

Commit

8747b25bcd9606418296906091674d97fd4b65a7

Source

github

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Breaking

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All attributes

project: gcc
subsystem: i386
patch_id: —
commit_hash: 8747b25bcd9606418296906091674d97fd4b65a7
source_type: github
headline: i386: Correct SSE vector concat patterns for SSE4.1
tldr: i386: Fixes incorrect conditions for SSE vec_concatv2{sf,si} patterns when SSE4.1 is enabled.
author: Uros Bizjak
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • i386
• sse
• optimization
• instruction-selection
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/8747b25bcd9606418296906091674d97fd4b65a7
date: 2026-09-10T00:00:00.000Z

This commit corrects instruction selection for SSE vector concatenation on x86. It fixes an incorrect condition in vec_concatv2sf and vec_concatv2si patterns, preventing them from being selected when SSE4.1 is available and the operands are not compatible with the SSE4.1 specific instructions. Additionally, the generic SSE patterns are now disabled when SSE4.1 is enabled to ensure the more appropriate SSE4.1 patterns are used.