[clang] [clang] Emitting a warning if optimizations are enabled with sanitizers (PR #95934)

[Fangrui Song via cfe-commits]

MaskRay wrote:

I agree that we should not add a driver diagnostic.
Using sanitizers with -O2/-O3 is pretty common, especially when user programs are so large that -O0 is too slow or does not build at all.
I think msan is the most affected sanitizer which will detect fewer bugs.


https://github.com/llvm/llvm-project/pull/95934