Some Cpp Core Guidelines warning fixes (#2116)

Co-authored-by: Stephan T. Lavavej <[email protected]>

Author: AlexGuteniev

stl/inc/atomic

@@ -524,8 +524,8 @@ inline void _Atomic_lock_acquire(long& _Spinlock) noexcept {
     // Algorithm from Intel(R) 64 and IA-32 Architectures Optimization Reference Manual, May 2020
     // Example 2-4. Contended Locks with Increasing Back-off Example - Improved Version, page 2-22
     // The code in mentioned manual is covered by the 0BSD license.
-    int _Current_backoff   = 1;
-    const int _Max_backoff = 64;
+    int _Current_backoff       = 1;
+    constexpr int _Max_backoff = 64;
     while (_InterlockedExchange(&_Spinlock, 1) != 0) {
         while (__iso_volatile_load32(&reinterpret_cast<int&>(_Spinlock)) != 0) {
             for (int _Count_down = _Current_backoff; _Count_down != 0; --_Count_down) {

stl/inc/charconv

@@ -980,7 +980,7 @@ void _Assemble_floating_point_infinity(const bool _Is_negative, _FloatingType& _
     _Uint_type _Sign_component = _Is_negative;
     _Sign_component <<= _Floating_traits::_Sign_shift;
 
-    const _Uint_type _Exponent_component = _Floating_traits::_Shifted_exponent_mask;
+    constexpr _Uint_type _Exponent_component = _Floating_traits::_Shifted_exponent_mask;
 
     _Result = _Bit_cast<_FloatingType>(_Sign_component | _Exponent_component);
 }
@@ -1227,12 +1227,12 @@ _NODISCARD errc _Assemble_floating_point_value_from_big_integer_flt(const _Big_i
     _FloatingType& _Result) noexcept {
     using _Traits = _Floating_type_traits<_FloatingType>;
 
-    const int32_t _Base_exponent = _Traits::_Mantissa_bits - 1;
+    constexpr int32_t _Base_exponent = _Traits::_Mantissa_bits - 1;
 
     // Very fast case: If we have 64 bits of precision or fewer,
     // we can just take the two low order elements from the _Big_integer_flt:
     if (_Integer_bits_of_precision <= 64) {
-        const int32_t _Exponent = _Base_exponent;
+        constexpr int32_t _Exponent = _Base_exponent;
 
         const uint32_t _Mantissa_low  = _Integer_value._Myused > 0 ? _Integer_value._Mydata[0] : 0;
         const uint32_t _Mantissa_high = _Integer_value._Myused > 1 ? _Integer_value._Mydata[1] : 0;
@@ -1335,7 +1335,7 @@ _NODISCARD errc _Convert_decimal_string_to_floating_type(
     // To generate an N bit mantissa we require N + 1 bits of precision. The extra bit is used to correctly round
     // the mantissa (if there are fewer bits than this available, then that's totally okay;
     // in that case we use what we have and we don't need to round).
-    const uint32_t _Required_bits_of_precision = static_cast<uint32_t>(_Traits::_Mantissa_bits + 1);
+    constexpr uint32_t _Required_bits_of_precision = static_cast<uint32_t>(_Traits::_Mantissa_bits + 1);
 
     // The input is of the form 0.mantissa * 10^exponent, where 'mantissa' are the decimal digits of the mantissa
     // and 'exponent' is the decimal exponent. We decompose the mantissa into two parts: an integer part and a
@@ -2167,7 +2167,7 @@ _NODISCARD to_chars_result _Floating_to_chars_hex_shortest(
         // C11 7.21.6.1 "The fprintf function"/8: "If the value is zero, the exponent is zero."
         // Special-casing zero is necessary because of the exponent.
         const char* const _Str = "0p+0";
-        const size_t _Len      = 4;
+        constexpr size_t _Len  = 4;
 
         if (_Last - _First < static_cast<ptrdiff_t>(_Len)) {
             return {_Last, errc::value_too_large};

stl/inc/coroutine

@@ -219,7 +219,7 @@ struct coroutine_handle<noop_coroutine_promise> {
 
     _NODISCARD noop_coroutine_promise& promise() const noexcept {
         // Returns a reference to the associated promise
-        return *reinterpret_cast<noop_coroutine_promise*>(__builtin_coro_promise(_Ptr, 0, false));
+        return *static_cast<noop_coroutine_promise*>(__builtin_coro_promise(_Ptr, 0, false));
     }
 
     _NODISCARD constexpr void* address() const noexcept {

stl/inc/execution

@@ -2813,9 +2813,9 @@ inline size_t _Get_stable_sort_tree_height(const size_t _Count, const size_t _Hw
     const auto _Ideal_chunks           = _Hw_threads * _Oversubscription_multiplier;
     const size_t _Log_ideal_chunks     = _Floor_of_log_2(_Ideal_chunks);
 #ifdef _WIN64
-    const size_t _Max_tree_height      = 62; // to avoid ptrdiff_t overflow
+    constexpr size_t _Max_tree_height  = 62; // to avoid ptrdiff_t overflow
 #else // ^^^ _WIN64 / !_WIN64 vvv
-    const size_t _Max_tree_height = 30;
+    constexpr size_t _Max_tree_height = 30;
 #endif // _WIN64
     const size_t _Clamped_ideal_chunks = (_STD min)(_Max_tree_height, _Log_ideal_chunks);
 

stl/inc/memory_resource

@@ -372,7 +372,7 @@ namespace pmr {
 #endif // _DEBUG
             }
 
-            _Oversized_header* _Hdr = reinterpret_cast<_Oversized_header*>(reinterpret_cast<char*>(_Ptr) + _Bytes) - 1;
+            _Oversized_header* _Hdr = reinterpret_cast<_Oversized_header*>(static_cast<char*>(_Ptr) + _Bytes) - 1;
 
             _STL_ASSERT(_Hdr->_Size == _Bytes && _Hdr->_Align == _Align,
                 "Cannot deallocate memory not allocated by this memory pool.");