Landing: 2c87d96c3115

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Project / Subsystem

gcc / tree-optimization

Date

2026-08-31

Author

Richard Biener

Commit

2c87d96c31157ef45c0bb80b04c444d6891ef108

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: tree-optimization
patch_id: —
commit_hash: 2c87d96c31157ef45c0bb80b04c444d6891ef108
source_type: github
headline: Fixes wrong code for vectorized reduction by restoring computation order.
tldr: Restores correct computation order for vectorized reduction to avoid wrong code.
author: Richard Biener
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • optimization
• vectorization
• bugfix
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/2c87d96c31157ef45c0bb80b04c444d6891ef108
date: 2026-08-31T00:00:00.000Z

This commit fixes wrong code generated for vectorized reduction operations by restoring the original computation order of vectype_in. The number of input vector types (vec_in_num) is now computed before the input array is potentially modified, ensuring correctness. A new test case is included to verify the fix.