Landing: 878b5b0030d4

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Project / Subsystem

gcc / tree-optimization

Date

2026-06-08

Author

Richard Biener

Commit

878b5b0030d4b42b94b7df38375d6bf5f187dc33

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: tree-optimization
patch_id: —
commit_hash: 878b5b0030d4b42b94b7df38375d6bf5f187dc33
source_type: github
headline: Forward propagation now preserves alignment for LHS assignments.
tldr: A bug in forward propagation that missed updating alignment for assignments to the left-hand side has been fixed.
author: Richard Biener
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • optimization
• bugfix
• alignment
• ssa
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/878b5b0030d4b42b94b7df38375d6bf5f187dc33
date: 2026-06-08T00:00:00.000Z

This commit fixes a bug in GCC’s forward propagation pass where the alignment of expressions was not correctly preserved when propagating values into the left-hand side of an assignment. This oversight, introduced in a previous fix, could lead to incorrect assumptions about memory access alignment, potentially causing performance issues or incorrect code generation. The fix ensures that the original access alignment is maintained during such propagations.