================ Comment at: lib/sanitizer_common/sanitizer_atomic_clang.h:70 @@ +69,3 @@ + v = a->val_dont_use; +#if defined(__i386__) || defined(__x86_64__) + // On x86 loads are implicitly acquire. ---------------- I would split this into multiple files (one with ifdef __arm__, etc) http://llvm-reviews.chandlerc.com/D2582