Landing: 675b6856ca66

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Project / Subsystem

gcc / libstdc++

Date

2026-07-28

Author

Tomasz Kamiński

Commit

675b6856ca66366632598cb0f5ccedbb337ccc0b

Source

github

Perf win

No

Breaking

No

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All attributes

project: gcc
subsystem: libstdc++
patch_id: —
commit_hash: 675b6856ca66366632598cb0f5ccedbb337ccc0b
source_type: github
headline: libstdc++: Lemire's algorithm adapted for non--bit ranges.
tldr: Random number generation in libstdc++ uses Lemire's algorithm more broadly for power-of-two ranges, improving portability.
author: Tomasz Kamiński
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • libstdc++
• random
• portability
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/675b6856ca66366632598cb0f5ccedbb337ccc0b
date: 2026-07-28T00:00:00.000Z

GCC’s libstdc++ now more broadly applies Lemire’s algorithm for generating random numbers within power-of-two ranges. Previously, this efficient algorithm was primarily used for 32-bit (__UINT32_TYPE__) and 64-bit (__UINT64_TYPE__) unsigned integers. This update allows it to work with targets that lack these specific types, by masking the result of integer conversions to the required bit width. The core logic for Lemire’s algorithm and the necessary type definitions are now consolidated in uniform_int_dist.h for better organization and portability.