Fix branching in isinf

Author: mborland

include/boost/safe_numbers/detail/float_basis.hpp

@@ -364,19 +364,17 @@ BOOST_SAFE_NUMBERS_HOST_DEVICE [[nodiscard]] constexpr auto modbyzero_mod_msg()
 
 namespace impl {
 
-// Clear the sign bit rather than branch on val < 0 which was frequently mis-predicted
 template <compatible_float_type T>
 BOOST_SAFE_NUMBERS_HOST_DEVICE [[nodiscard]] constexpr auto constexpr_abs(const T val) noexcept -> T
 {
-    using bit_type = std::conditional_t<std::is_same_v<T, float>, std::uint32_t, std::uint64_t>;
-    constexpr bit_type mask {static_cast<bit_type>(~(bit_type{1} << (sizeof(T) * 8U - 1U)))};
-    return std::bit_cast<T>(static_cast<bit_type>(std::bit_cast<bit_type>(val) & mask));
+    return val < 0 ? -val : val;
 }
 
+// Two-sided compare rather than constexpr_abs(val) > max()
 template <compatible_float_type T>
 BOOST_SAFE_NUMBERS_HOST_DEVICE [[nodiscard]] constexpr auto constexpr_isinf(const T val) noexcept -> bool
 {
-    return constexpr_abs(val) > std::numeric_limits<T>::max();
+    return (val > std::numeric_limits<T>::max()) | (val < std::numeric_limits<T>::lowest());
 }
 
 // val != val is the canonical NAN test