9ddc85f6d5
Part of #147386 in preparation for: https://discourse.llvm.org/t/rfc-make-clang-builtin-math-functions-constexpr-with-llvm-libc-to-support-c-23-constexpr-math-functions/86450
66 lines
2.0 KiB
C++
66 lines
2.0 KiB
C++
//===-- Implementation header for coshf -------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_COSHF_H
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#define LLVM_LIBC_SRC___SUPPORT_MATH_COSHF_H
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#include "sinhfcoshf_utils.h"
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#include "src/__support/FPUtil/FEnvImpl.h"
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#include "src/__support/FPUtil/FPBits.h"
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#include "src/__support/FPUtil/rounding_mode.h"
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#include "src/__support/macros/config.h"
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#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
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namespace LIBC_NAMESPACE_DECL {
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namespace math {
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LIBC_INLINE static constexpr float coshf(float x) {
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using namespace sinhfcoshf_internal;
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using FPBits = typename fputil::FPBits<float>;
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FPBits xbits(x);
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xbits.set_sign(Sign::POS);
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x = xbits.get_val();
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uint32_t x_u = xbits.uintval();
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// When |x| >= 90, or x is inf or nan
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if (LIBC_UNLIKELY(x_u >= 0x42b4'0000U || x_u <= 0x3280'0000U)) {
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// |x| <= 2^-26
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if (x_u <= 0x3280'0000U) {
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return 1.0f + x;
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}
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if (xbits.is_inf_or_nan())
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return x + FPBits::inf().get_val();
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int rounding = fputil::quick_get_round();
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if (LIBC_UNLIKELY(rounding == FE_DOWNWARD || rounding == FE_TOWARDZERO))
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return FPBits::max_normal().get_val();
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fputil::set_errno_if_required(ERANGE);
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fputil::raise_except_if_required(FE_OVERFLOW);
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return x + FPBits::inf().get_val();
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}
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// TODO: We should be able to reduce the latency and reciprocal throughput
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// further by using a low degree (maybe 3-7 ?) minimax polynomial for small
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// but not too small inputs, such as |x| < 2^-2, or |x| < 2^-3.
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// cosh(x) = (e^x + e^(-x)) / 2.
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return static_cast<float>(exp_pm_eval</*is_sinh*/ false>(x));
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}
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} // namespace math
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} // namespace LIBC_NAMESPACE_DECL
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#endif // LLVM_LIBC_SRC___SUPPORT_MATH_COSHF_H
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