Landing: 610f1166538a

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Project / Subsystem

gcc / tree-optimization

Date

2026-07-28

Author

Andrea Pinski

Commit

610f1166538ad2e637c913be78b074100270cc5c

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: tree-optimization
patch_id: —
commit_hash: 610f1166538ad2e637c913be78b074100270cc5c
source_type: github
headline: match: Fix signed integer overflow in pattern for `cmp + (-cmp ^ x)`
tldr: Corrects a GCC pattern that introduced unintended signed integer overflow with INT_MIN.
author: Andrea Pinski
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • optimization
• bugfix
• integer overflow
• pattern matching
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/610f1166538ad2e637c913be78b074100270cc5c
date: 2026-07-28T00:00:00.000Z

A recent addition to GCC’s pattern matching system inadvertently introduced signed integer overflow for specific inputs, particularly when dealing with INT_MIN. The pattern cmp + (-cmp ^ x) was incorrectly translated, causing overflow when x was INT_MIN and cmp was 0. This commit fixes the issue by using an unsigned type for the negation, preventing the overflow.