[libcxx-commits] [libcxx] [libcxx][test] Prevent compiler optimising out uses of 64-bit atomics (PR #172517)

[David Spickett via libcxx-commits]

DavidSpickett wrote:

https://libcxx.llvm.org/TestingLibcxx.html mentions optimisations only in the context of benchmarks, so I do not know what expectations are for tests. Is it assumed that they are going to be run at -O0 generally? That seems reasonable, as we are not testing for optimisation here.

Glancing at the files in `libcxx/test/configs` all the `config.substitutions.append(('%{compile_flags}'` do not include compiler optimisation flags.

If it's generally assumed they'll be run at -O0 then there's no need for the changes in this PR.

https://github.com/llvm/llvm-project/pull/172517