[libc++] Don't bother asserting that <bit> functions get unsigned types (#161487)

philnik777 · web-flow · commit b88af6635c20 · 2025-10-07T10:29:20.000+02:00
The builtins already diagnose types other than unsigned integers, so
there is no point in `static_assert`ing that again.
diff --git a/libcxx/include/__bit/countl.h b/libcxx/include/__bit/countl.h
@@ -24,7 +24,6 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int __countl_zero(_Tp __t) _NOEXCEPT {
-  static_assert(__is_unsigned_integer_v<_Tp>, "__countl_zero requires an unsigned integer type");
   return __builtin_clzg(__t, numeric_limits<_Tp>::digits);
 }
 
diff --git a/libcxx/include/__bit/countr.h b/libcxx/include/__bit/countr.h
@@ -24,7 +24,6 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __countr_zero(_Tp __t) _NOEXCEPT {
-  static_assert(__is_unsigned_integer_v<_Tp>, "__countr_zero only works with unsigned types");
   return __builtin_ctzg(__t, numeric_limits<_Tp>::digits);
 }
 
diff --git a/libcxx/include/__bit/popcount.h b/libcxx/include/__bit/popcount.h
@@ -23,7 +23,6 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __popcount(_Tp __t) _NOEXCEPT {
-  static_assert(__is_unsigned_integer_v<_Tp>, "__popcount only works with unsigned types");
   return __builtin_popcountg(__t);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -24,7 +24,6 @@ _LIBCPP_BEGIN_NAMESPACE_STD`
`24`	`24`
`25`	`25`	`template <class _Tp>`
`26`	`26`	`_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int __countl_zero(_Tp __t) _NOEXCEPT {`
`27`		`- static_assert(__is_unsigned_integer_v<_Tp>, "__countl_zero requires an unsigned integer type");`
`28`	`27`	`return __builtin_clzg(__t, numeric_limits<_Tp>::digits);`
`29`	`28`	`}`
`30`	`29`
Original file line number	Diff line number	Diff line change
`@@ -23,7 +23,6 @@ _LIBCPP_BEGIN_NAMESPACE_STD`
`23`	`23`
`24`	`24`	`template <class _Tp>`
`25`	`25`	`[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __popcount(_Tp __t) _NOEXCEPT {`
`26`		`- static_assert(__is_unsigned_integer_v<_Tp>, "__popcount only works with unsigned types");`
`27`	`26`	`return __builtin_popcountg(__t);`
`28`	`27`	`}`
`29`	`28`