[all-commits] [llvm/llvm-project] 2fec52: tsan: model atomic read for failing CAS

[Dmitry Vyukov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 2fec52a40261ecab7fc621184159f464c67dcfa4
      https://github.com/llvm/llvm-project/commit/2fec52a40261ecab7fc621184159f464c67dcfa4
  Author: Dmitry Vyukov <dvyukov at google.com>
  Date:   2022-05-02 (Mon, 02 May 2022)

  Changed paths:
    M compiler-rt/lib/tsan/rtl/tsan_interface_atomic.cpp
    A compiler-rt/test/tsan/atomic_norace3.cpp

  Log Message:
  -----------
  tsan: model atomic read for failing CAS

See the added test and https://github.com/google/sanitizers/issues/1520
for the description of the problem.
The standard says that failing CAS is a memory load only,
model it as such to avoid false positives.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D124507