Landing: 9af2878b87da

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Project / Subsystem

gcc / gcc

Date

2026-09-15

Author

Richard Biener

Commit

9af2878b87da1f7890c17c50680fb8390936e38a

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: gcc
patch_id: —
commit_hash: 9af2878b87da1f7890c17c50680fb8390936e38a
source_type: github
headline: gcc: Prevent vectorizing conversions from _BitInt with incorrect extension
tldr: Fixes vectorization of _BitInt conversions in GCC by adding a check for proper sign/zero extension.
author: Richard Biener
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • gcc
• optimization
• vectorization
• _BitInt
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/9af2878b87da1f7890c17c50680fb8390936e38a
date: 2026-09-15T00:00:00.000Z

This commit improves GCC’s vectorization capabilities by adding a crucial check to prevent the vectorization of conversions from _BitInt types. Specifically, it ensures that _BitInt values are appropriately sign-extended or zero-extended to match the target mode before vectorization occurs, avoiding potential incorrect results. A new test case, vect-bitint-1.c, is included to verify this correction.