Landing: ea57201777f8

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Project / Subsystem

gcc / libstdc++

Date

2026-05-21

Author

Patrick Palka

Commit

ea57201777f8cb58766953f87880bcf89244411b

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: libstdc++
patch_id: —
commit_hash: ea57201777f8cb58766953f87880bcf89244411b
source_type: github
headline: Libstdc++: Fix recent std::flat_map test with COW std::string
tldr: The std::flat_map test is fixed to disable constant evaluation when std::string is not constexpr.
author: Patrick Palka
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • libstdc++
• testsuite
• flat_map
• constexpr
• std::string
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/ea57201777f8cb58766953f87880bcf89244411b
date: 2026-05-21T00:00:00.000Z

A recent test added for std::flat_map in libstdc++ used std::string in a context requiring constant evaluation. However, std::string is not always constexpr, particularly when using a copy-on-write (COW) implementation. This commit fixes the test by disabling constant evaluation when std::string is not constexpr, ensuring the test passes in all configurations.