tree e153a3d7d0539236e452a17245d7e8f2e9e067b8
parent 98748087682a940ad4d5f9dba2bef85e610d6c7f
author Schrodinger ZHU Yifan <yifanzhu@rochester.edu> 1715356502 -0400
committer Copybara-Service <copybara-worker@google.com> 1715362702 -0700

[libc] avoid cmpxchg on the fastpath of callonce (#91748)

Avoid `cmpxchg` operation if the function has already been called.
The destination operand of `cmpxchg` may receive a write cycle without
regard to the result of the comparison

GitOrigin-RevId: b8f4f39d3d43d348e31fc5709b72e1f51392e52d