Landing: 6a000bf53e6f

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Project / Subsystem

gcc / tree-optimization

Date

2026-08-14

Author

Richard Biener

Commit

6a000bf53e6f42cff3774822227f47e39d2b76d5

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: tree-optimization
patch_id: —
commit_hash: 6a000bf53e6f42cff3774822227f47e39d2b76d5
source_type: github
headline: Verify SLP schedule also for PHIs
tldr: Ensures SLP vectorizer correctly handles PHI nodes in scheduled code.
author: Richard Biener
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • optimization
• vectorization
• PHI nodes
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/6a000bf53e6f42cff3774822227f47e39d2b76d5
date: 2026-08-14T00:00:00.000Z

This commit enhances the SLP (Sliding Window Parallelization) vectorizer to correctly verify scheduling for PHI nodes. It ensures that the insertion place of the schedule dominates the PHI argument edges. This fix prevents potential issues with vectorization when PHI nodes are involved and includes a new test case.