libstdc++: Remove redundant check for zero in std::__popcount

The popcount built-ins work fine for zero, so there's no need to check
for it.

libstdc++-v3/ChangeLog:

	* include/std/bit (__popcount): Remove redundant check for zero.

diff --git a/libstdc++-v3/include/std/bit b/libstdc++-v3/include/std/bit
index f434482..16f7eba 100644 (file)
--- a/libstdc++-v3/include/std/bit
+++ b/libstdc++-v3/include/std/bit
@@ -184,9 +184,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       using __gnu_cxx::__int_traits;
       constexpr auto _Nd = __int_traits<_Tp>::__digits;
 
-      if (__x == 0)
-        return 0;
-
       constexpr auto _Nd_ull = __int_traits<unsigned long long>::__digits;
       constexpr auto _Nd_ul = __int_traits<unsigned long>::__digits;
       constexpr auto _Nd_u = __int_traits<unsigned>::__digits;