tree d3ffbcd0c0f1ba479438720326705699d4757c8a
parent 862f4cfc86c122bace7f1b7ad3f289b8a135a08a
author Alex Richardson <Alexander.Richardson@cl.cam.ac.uk> 1610106784 +0000
committer Copybara-Service <copybara-worker@google.com> 1610322347 -0800

[compiler-rt] Implement __atomic_is_lock_free

This function is called by the __atomic_is_lock_free() builtin if the value
cannot be resolved to true at compile time. Lack of this function is
causing the non-lockfree atomics tests in libc++ to not be run (see D91911)

This function is also added in D85044, but that review also adds support
for using lock-free atomics in more cases, whereas this is a minimal change
that just adds __atomic_is_lock_free() for the implementation of atomic.c.

Reviewed By: ldionne

Differential Revision: https://reviews.llvm.org/D92302

GitOrigin-RevId: 00530dee5d1295dc20ebafdd9a8a79662f41513e