Red Hat Summit Red Hat SummitSuporteConsoleDesenvolvedoresComeçar um testeContato

Este conteúdo não está disponível no idioma selecionado.

Chapter 5. Changes in LLVM Toolset

LLVM Toolset has been updated from version 17.0.6 to 18.1.8 on RHEL 8 and RHEL 9.

Notable LLVM updates:

  • The constant expression variants of the following instructions have been removed: and, or, lshr, ashr, zext, sext, fptrunc, fpext, fptoui, fptosi, uitofp, sitofp.
  • The llvm.exp10 intrinsic has been added.
  • The code_model attribute for global variables has been added.
  • The backend for the AArch64, AMDGPU, PowerPC, RISC-V, SystemZ and x86 architectures has been improved.
  • LLVM tools have been improved.

Notable Clang enhancements:

  • C++20 feature support:

    • Clang no longer performs One Definition Rule (ODR) checks for declarations in the global module fragment. To enable more strict behavior, use the -Xclang -fno-skip-odr-check-in-gmf option.

  • C++23 feature support:

    • A new diagnostic flag -Wc++23-lambda-attributes has been added to warn about the use of attributes on lambdas.

  • C++2c feature support:

    • Clang now allows using the _ character as a placeholder variable name multiple times in the same scope.
    • Attributes now expect unevaluated strings in attribute parameters that are string literals.
    • The deprecated arithmetic conversion on enumerations from C++26 has been removed.
    • The specification of template parameter initialization has been improved.
  • For a complete list of changes, see the upstream release notes for Clang.

ABI changes in Clang:

  • Following the SystemV ABI for x86_64, the __int128 arguments are no longer split between a register and a stack slot.
  • For more information, see the list of ABI changes in Clang.

Notable backwards incompatible changes:

  • A bug fix in the reversed argument order for templated operators breaks code in C++20 that was previously accepted in C++17.
  • The GCC_INSTALL_PREFIX CMake variable (which sets the default --gcc-toolchain=) is deprecated and will be removed. Specify the --gcc-install-dir= or --gcc-triple= option in a configuration file instead.
  • The default extension name for precompiled headers (PCH) generation (-c -xc-header and -c -xc++-header) is now .pch instead of .gch.
  • When -include a.h probes the a.h.gch file, the include now ignores a.h.gch if it is not a Clang PCH file or a directory containing any Clang PCH file.
  • A bug that caused __has_cpp_attribute and __has_c_attribute to return incorrect values for certain C++-11-style attributes has been fixed.
  • A bug in finding a matching operator!= while adding a reversed operator== has been fixed.
  • The name mangling rules for function templates have been changed to accept that functions can be overloaded on their template parameter lists or requires-clauses.
  • The -Wenum-constexpr-conversion warning is now enabled by default on system headers and macros. It will be turned into a hard (non-downgradable) error in the next Clang release.
  • A path to the imported modules for C++20 named modules can no longer be hardcoded. You must specify all the dependent modules from the command line.
  • It is no longer possible to import modules by using import <module>; Clang uses explicitly-built modules.
  • For more details, see the list of potentially breaking changes.

For detailed information regarding the updates, see the upstream LLVM release notes and Clang release notes.

Red Hat logoGithubredditYoutubeTwitter

Aprender

Experimente, compre e venda

Comunidades

Sobre a documentação da Red Hat

Ajudamos os usuários da Red Hat a inovar e atingir seus objetivos com nossos produtos e serviços com conteúdo em que podem confiar. Explore nossas atualizações recentes.

Tornando o open source mais inclusivo

A Red Hat está comprometida em substituir a linguagem problemática em nosso código, documentação e propriedades da web. Para mais detalhes veja o Blog da Red Hat.

Sobre a Red Hat

Fornecemos soluções robustas que facilitam o trabalho das empresas em plataformas e ambientes, desde o data center principal até a borda da rede.

Theme

© 2026 Red HatVoltar ao topo