46 lines
1.0 KiB
C
46 lines
1.0 KiB
C
// { dg-do compile }
|
|
// { dg-options "-O2 -std=gnu++11 -fdump-tree-optimized" } */
|
|
|
|
#include <array>
|
|
|
|
// Return a copy of the underlying memory of an arbitrary value.
|
|
template <
|
|
typename T,
|
|
typename = typename std::enable_if<std::is_trivially_copyable<T>::value>::type
|
|
>
|
|
auto getMem(
|
|
T const & value
|
|
) -> std::array<char, sizeof(T)> {
|
|
auto ret = std::array<char, sizeof(T)>{};
|
|
__builtin_memcpy(ret.data(), &value, sizeof(T));
|
|
return ret;
|
|
}
|
|
|
|
template <
|
|
typename T,
|
|
typename = typename std::enable_if<std::is_trivially_copyable<T>::value>::type
|
|
>
|
|
auto fromMem(
|
|
std::array<char, sizeof(T)> const & buf
|
|
) -> T {
|
|
auto ret = T{};
|
|
__builtin_memcpy(&ret, buf.data(), sizeof(T));
|
|
return ret;
|
|
}
|
|
|
|
double foo1(std::uint64_t arg) {
|
|
return fromMem<double>(getMem(arg));
|
|
}
|
|
|
|
double foo2(std::uint64_t arg) {
|
|
return *reinterpret_cast<double*>(&arg);
|
|
}
|
|
|
|
double foo3(std::uint64_t arg) {
|
|
double ret;
|
|
__builtin_memcpy(&ret, &arg, sizeof(arg));
|
|
return ret;
|
|
}
|
|
|
|
// { dg-final { scan-tree-dump-not "BIT_FIELD_REF" "optimized" } }
|