https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120895
--- Comment #29 from David C. Partridge <david.partridge at perdrix dot co.uk> --- And somehow macOS g++ gets it (almost) correct: amonra@lethe m512 % g++ --version Apple clang version 15.0.0 (clang-1500.1.0.2.5) Target: x86_64-apple-darwin22.6.0 Thread model: posix InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin amonra@lethe m512 % g++ m512.cpp -std=c++20 amonra@lethe m512 % ./a.out std::alignment_of_v<__m512> is: 16 alignof(__m512) is: 64 __alignof__(__m512) is: 64 Address of data%64: 0 Address1%64: 0 Address2%64: 0 amonra@lethe m512 %
