gcc, like other compilers, has it's own documented extensions which are used in many projects (such as the linux kernel, but also many interpreters/vms using direct threading for example).
The clang devs try to support them nonetheless for compatibility, except, for what I understand, a few that are explicitly unsupported by design.
The clang devs try to support them nonetheless for compatibility, except, for what I understand, a few that are explicitly unsupported by design.