Author: danalbert Date: Tue Jan 6 12:39:37 2015 New Revision: 225280 URL: http://llvm.org/viewvc/llvm-project?rev=225280&view=rev Log: Obey [atomics.types.operations.req]/21 for GCC.
Summary: Excerpt from [atomics.types.operations.req]/21: > When only one memory_order argument is supplied, the value of > success is order, and the value of failure is order except that a > value of memory_order_acq_rel shall be replaced by the value > memory_order_acquire and a value of memory_order_release shall be > replaced by the value memory_order_relaxed. Clean up some copy pasta while I'm here (someone added a return statement to a void function). Reviewers: EricWF, jroelofs, mclow.lists Reviewed By: mclow.lists Subscribers: cfe-commits Differential Revision: http://reviews.llvm.org/D6632 Added: libcxx/trunk/test/atomics/ libcxx/trunk/test/atomics/atomics.general/ libcxx/trunk/test/atomics/atomics.general/replace_failure_order.pass.cpp Modified: libcxx/trunk/include/atomic Modified: libcxx/trunk/include/atomic URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/atomic?rev=225280&r1=225279&r2=225280&view=diff ============================================================================== --- libcxx/trunk/include/atomic (original) +++ libcxx/trunk/include/atomic Tue Jan 6 12:39:37 2015 @@ -583,6 +583,16 @@ static inline constexpr int __to_gcc_ord __ATOMIC_CONSUME)))); } +static inline constexpr int __to_gcc_failure_order(memory_order __order) { + // Avoid switch statement to make this a constexpr. + return __order == memory_order_relaxed ? __ATOMIC_RELAXED: + (__order == memory_order_acquire ? __ATOMIC_ACQUIRE: + (__order == memory_order_release ? __ATOMIC_RELAXED: + (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST: + (__order == memory_order_acq_rel ? __ATOMIC_ACQUIRE: + __ATOMIC_CONSUME)))); +} + } // namespace __gcc_atomic template <typename _Tp> @@ -637,8 +647,8 @@ static inline void __c11_atomic_store(vo template <typename _Tp> static inline void __c11_atomic_store(_Atomic(_Tp)* __a, _Tp __val, memory_order __order) { - return __atomic_store(&__a->__a_value, &__val, - __gcc_atomic::__to_gcc_order(__order)); + __atomic_store(&__a->__a_value, &__val, + __gcc_atomic::__to_gcc_order(__order)); } template <typename _Tp> @@ -683,7 +693,7 @@ static inline bool __c11_atomic_compare_ return __atomic_compare_exchange(&__a->__a_value, __expected, &__value, false, __gcc_atomic::__to_gcc_order(__success), - __gcc_atomic::__to_gcc_order(__failure)); + __gcc_atomic::__to_gcc_failure_order(__failure)); } template <typename _Tp> @@ -693,7 +703,7 @@ static inline bool __c11_atomic_compare_ return __atomic_compare_exchange(&__a->__a_value, __expected, &__value, false, __gcc_atomic::__to_gcc_order(__success), - __gcc_atomic::__to_gcc_order(__failure)); + __gcc_atomic::__to_gcc_failure_order(__failure)); } template <typename _Tp> @@ -703,7 +713,7 @@ static inline bool __c11_atomic_compare_ return __atomic_compare_exchange(&__a->__a_value, __expected, &__value, true, __gcc_atomic::__to_gcc_order(__success), - __gcc_atomic::__to_gcc_order(__failure)); + __gcc_atomic::__to_gcc_failure_order(__failure)); } template <typename _Tp> @@ -713,7 +723,7 @@ static inline bool __c11_atomic_compare_ return __atomic_compare_exchange(&__a->__a_value, __expected, &__value, true, __gcc_atomic::__to_gcc_order(__success), - __gcc_atomic::__to_gcc_order(__failure)); + __gcc_atomic::__to_gcc_failure_order(__failure)); } template <typename _Tp> Added: libcxx/trunk/test/atomics/atomics.general/replace_failure_order.pass.cpp URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/atomics/atomics.general/replace_failure_order.pass.cpp?rev=225280&view=auto ============================================================================== --- libcxx/trunk/test/atomics/atomics.general/replace_failure_order.pass.cpp (added) +++ libcxx/trunk/test/atomics/atomics.general/replace_failure_order.pass.cpp Tue Jan 6 12:39:37 2015 @@ -0,0 +1,41 @@ +//===----------------------------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is dual licensed under the MIT and the University of Illinois Open +// Source Licenses. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +// This test verifies behavior specified by [atomics.types.operations.req]/21: +// +// When only one memory_order argument is supplied, the value of success is +// order, and the value of failure is order except that a value of +// memory_order_acq_rel shall be replaced by the value memory_order_acquire +// and a value of memory_order_release shall be replaced by the value +// memory_order_relaxed. +// +// Clang's atomic intrinsics do this for us, but GCC's do not. We don't actually +// have visibility to see what these memory orders are lowered to, but we can at +// least check that they are lowered at all (otherwise there is a compile +// failure with GCC). + +#include <atomic> + +int main() { + std::atomic<int> i; + volatile std::atomic<int> v; + int exp; + + i.compare_exchange_weak(exp, 0, std::memory_order_acq_rel); + i.compare_exchange_weak(exp, 0, std::memory_order_release); + i.compare_exchange_strong(exp, 0, std::memory_order_acq_rel); + i.compare_exchange_strong(exp, 0, std::memory_order_release); + + v.compare_exchange_weak(exp, 0, std::memory_order_acq_rel); + v.compare_exchange_weak(exp, 0, std::memory_order_release); + v.compare_exchange_strong(exp, 0, std::memory_order_acq_rel); + v.compare_exchange_strong(exp, 0, std::memory_order_release); + + return 0; +} _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
