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Work around PR31864 - ATOMIC_LLONG_LOCK_FREE is incorrect in 32 bit builds

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@307517 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Fiselier
2017-07-10 04:16:50 +00:00
parent 631d697c62
commit 3f22e24981
1 changed files with 35 additions and 2 deletions
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37
test/std/atomics/atomics.lockfree/isalwayslockfree.pass.cpp
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@@ -25,6 +25,40 @@ template <typename T> void checkAlwaysLockFree() {
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));
}