Author: ericwf Date: Sun Jul 9 21:16:50 2017 New Revision: 307517 URL: http://llvm.org/viewvc/llvm-project?rev=307517&view=rev Log: Work around PR31864 - ATOMIC_LLONG_LOCK_FREE is incorrect in 32 bit builds
Modified: libcxx/trunk/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp Modified: libcxx/trunk/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp?rev=307517&r1=307516&r2=307517&view=diff ============================================================================== --- libcxx/trunk/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp (original) +++ libcxx/trunk/test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp Sun Jul 9 21:16:50 2017 @@ -25,6 +25,40 @@ template <typename T> void checkAlwaysLo assert(std::atomic<T>().is_lock_free()); } +// FIXME: This separate test is needed to work around llvm.org/PR31864 +// which causes ATOMIC_LLONG_LOCK_FREE to be defined as '1' in 32-bit builds +// even though __atomic_always_lock_free returns true for the same type. +constexpr bool NeedWorkaroundForPR31864 = +#if defined(__clang__) +(sizeof(void*) == 4); // Needed on 32 bit builds +#else +false; +#endif + +template <bool Disable = NeedWorkaroundForPR31864, + std::enable_if_t<!Disable>* = nullptr, + class LLong = long long, + class ULLong = unsigned long long> +void checkLongLongTypes() { + static_assert(std::atomic<LLong>::is_always_lock_free == (2 == ATOMIC_LLONG_LOCK_FREE)); + static_assert(std::atomic<ULLong>::is_always_lock_free == (2 == ATOMIC_LLONG_LOCK_FREE)); +} + +// Used to make the calls to __atomic_always_lock_free dependent on a template +// parameter. +template <class T> constexpr size_t getSizeOf() { return sizeof(T); } + +template <bool Enable = NeedWorkaroundForPR31864, + std::enable_if_t<Enable>* = nullptr, + class LLong = long long, + class ULLong = unsigned long long> +void checkLongLongTypes() { + constexpr bool ExpectLockFree = __atomic_always_lock_free(getSizeOf<LLong>(), 0); + static_assert(std::atomic<LLong>::is_always_lock_free == ExpectLockFree, ""); + static_assert(std::atomic<ULLong>::is_always_lock_free == ExpectLockFree, ""); + static_assert((0 != ATOMIC_LLONG_LOCK_FREE) == ExpectLockFree, ""); +} + int main() { // structs and unions can't be defined in the template invocation. @@ -94,8 +128,7 @@ int main() static_assert(std::atomic<unsigned int>::is_always_lock_free == (2 == ATOMIC_INT_LOCK_FREE)); static_assert(std::atomic<long>::is_always_lock_free == (2 == ATOMIC_LONG_LOCK_FREE)); static_assert(std::atomic<unsigned long>::is_always_lock_free == (2 == ATOMIC_LONG_LOCK_FREE)); - static_assert(std::atomic<long long>::is_always_lock_free == (2 == ATOMIC_LLONG_LOCK_FREE)); - static_assert(std::atomic<unsigned long long>::is_always_lock_free == (2 == ATOMIC_LLONG_LOCK_FREE)); + checkLongLongTypes(); static_assert(std::atomic<void*>::is_always_lock_free == (2 == ATOMIC_POINTER_LOCK_FREE)); static_assert(std::atomic<std::nullptr_t>::is_always_lock_free == (2 == ATOMIC_POINTER_LOCK_FREE)); } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits