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1//===-- Conversion between floating-point types -----------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef LLVM_LIBC_SRC___SUPPORT_FPUTIL_CAST_H10#define LLVM_LIBC_SRC___SUPPORT_FPUTIL_CAST_H11 12#include "FPBits.h"13#include "dyadic_float.h"14#include "hdr/fenv_macros.h"15#include "src/__support/CPP/algorithm.h"16#include "src/__support/CPP/type_traits.h"17#include "src/__support/macros/properties/types.h"18 19namespace LIBC_NAMESPACE::fputil {20 21// TODO: Add optimization for known good targets with fast22// float to float16 conversion:23// https://github.com/llvm/llvm-project/issues/13351724template <typename OutType, typename InType>25LIBC_INLINE constexpr cpp::enable_if_t<cpp::is_floating_point_v<OutType> &&26 cpp::is_floating_point_v<InType>,27 OutType>28cast(InType x) {29 // Casting to the same type is a no-op.30 if constexpr (cpp::is_same_v<InType, OutType>) {31 return x;32 } else {33 if constexpr (cpp::is_same_v<OutType, bfloat16> ||34 cpp::is_same_v<InType, bfloat16>35#if defined(LIBC_TYPES_HAS_FLOAT16) && !defined(__LIBC_USE_FLOAT16_CONVERSION)36 || cpp::is_same_v<OutType, float16> ||37 cpp::is_same_v<InType, float16>38#endif39 ) {40 using InFPBits = FPBits<InType>;41 using InStorageType = typename InFPBits::StorageType;42 using OutFPBits = FPBits<OutType>;43 using OutStorageType = typename OutFPBits::StorageType;44 45 InFPBits x_bits(x);46 47 if (x_bits.is_nan()) {48 if (x_bits.is_signaling_nan()) {49 raise_except_if_required(FE_INVALID);50 return OutFPBits::quiet_nan().get_val();51 }52 53 InStorageType x_mant = x_bits.get_mantissa();54 if (InFPBits::FRACTION_LEN > OutFPBits::FRACTION_LEN)55 x_mant >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;56 return OutFPBits::quiet_nan(x_bits.sign(),57 static_cast<OutStorageType>(x_mant))58 .get_val();59 }60 61 if (x_bits.is_inf())62 return OutFPBits::inf(x_bits.sign()).get_val();63 64 constexpr size_t MAX_FRACTION_LEN =65 cpp::max(OutFPBits::FRACTION_LEN, InFPBits::FRACTION_LEN);66 DyadicFloat<cpp::bit_ceil(MAX_FRACTION_LEN)> xd(x);67 return xd.template as<OutType, /*ShouldSignalExceptions=*/true>();68 } else {69 return static_cast<OutType>(x);70 }71 }72}73 74} // namespace LIBC_NAMESPACE::fputil75 76#endif // LLVM_LIBC_SRC___SUPPORT_FPUTIL_CAST_H77