diff --git a/libc/shared/math.h b/libc/shared/math.h index 5126e46c9772e..9e76e710ecb01 100644 --- a/libc/shared/math.h +++ b/libc/shared/math.h @@ -84,6 +84,7 @@ #include "math/rsqrtf.h" #include "math/rsqrtf16.h" #include "math/sin.h" +#include "math/sinf.h" #include "math/tan.h" #include "math/tanf.h" diff --git a/libc/shared/math/sinf.h b/libc/shared/math/sinf.h new file mode 100644 index 0000000000000..5157b1e2d7cdc --- /dev/null +++ b/libc/shared/math/sinf.h @@ -0,0 +1,23 @@ +//===-- Shared sinf function ------------------------------------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_LIBC_SHARED_MATH_SINF_H +#define LLVM_LIBC_SHARED_MATH_SINF_H + +#include "shared/libc_common.h" +#include "src/__support/math/sinf.h" + +namespace LIBC_NAMESPACE_DECL { +namespace shared { + +using math::sinf; + +} // namespace shared +} // namespace LIBC_NAMESPACE_DECL + +#endif // LLVM_LIBC_SHARED_MATH_SINF_H diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt index d18ebc03ba7b8..a91d766774e8e 100644 --- a/libc/src/__support/math/CMakeLists.txt +++ b/libc/src/__support/math/CMakeLists.txt @@ -1234,6 +1234,22 @@ add_header_library( libc.src.__support.macros.optimization ) +add_header_library( + sinf + HDRS + sinf.h + DEPENDS + .range_reduction + .sincosf_utils + libc.src.__support.FPUtil.basic_operations + libc.src.__support.FPUtil.fenv_impl + libc.src.__support.FPUtil.fma + libc.src.__support.FPUtil.fp_bits + libc.src.__support.FPUtil.polyeval + libc.src.__support.FPUtil.rounding_mode + libc.src.__support.macros.optimization +) + add_header_library( dfmal HDRS diff --git a/libc/src/__support/math/sinf.h b/libc/src/__support/math/sinf.h new file mode 100644 index 0000000000000..9290444b43619 --- /dev/null +++ b/libc/src/__support/math/sinf.h @@ -0,0 +1,194 @@ +//===-- Single-precision sin function -------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_SINF_H +#define LLVM_LIBC_SRC___SUPPORT_MATH_SINF_H + +#include "src/__support/FPUtil/BasicOperations.h" +#include "src/__support/FPUtil/FEnvImpl.h" +#include "src/__support/FPUtil/FPBits.h" +#include "src/__support/FPUtil/PolyEval.h" +#include "src/__support/FPUtil/multiply_add.h" +#include "src/__support/FPUtil/rounding_mode.h" +#include "src/__support/macros/config.h" +#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY +#include "src/__support/macros/properties/cpu_features.h" // LIBC_TARGET_CPU_HAS_FMA + +#if defined(LIBC_MATH_HAS_SKIP_ACCURATE_PASS) && \ + defined(LIBC_MATH_HAS_INTERMEDIATE_COMP_IN_FLOAT) && \ + defined(LIBC_TARGET_CPU_HAS_FMA_FLOAT) + +#include "sincosf_float_eval.h" + +namespace LIBC_NAMESPACE_DECL { + +namespace math { + +LIBC_INLINE static float sinf(float x) { + return math::sincosf_float_eval::sincosf_eval(x); +} + +} // namespace math + +} // namespace LIBC_NAMESPACE_DECL + +#else // !LIBC_MATH_HAS_INTERMEDIATE_COMP_IN_FLOAT + +#include "src/__support/math/sincosf_utils.h" + +#ifdef LIBC_TARGET_CPU_HAS_FMA_DOUBLE +#include "src/__support/math/range_reduction_fma.h" +#else // !LIBC_TARGET_CPU_HAS_FMA_DOUBLE +#include "src/__support/math/range_reduction.h" +#endif // LIBC_TARGET_CPU_HAS_FMA_DOUBLE + +namespace LIBC_NAMESPACE_DECL { + +namespace math { + +LIBC_INLINE static float sinf(float x) { + using FPBits = typename fputil::FPBits; + FPBits xbits(x); + + uint32_t x_u = xbits.uintval(); + uint32_t x_abs = x_u & 0x7fff'ffffU; + double xd = static_cast(x); + + // Range reduction: + // For |x| > pi/32, we perform range reduction as follows: + // Find k and y such that: + // x = (k + y) * pi/32 + // k is an integer + // |y| < 0.5 + // For small range (|x| < 2^45 when FMA instructions are available, 2^22 + // otherwise), this is done by performing: + // k = round(x * 32/pi) + // y = x * 32/pi - k + // For large range, we will omit all the higher parts of 32/pi such that the + // least significant bits of their full products with x are larger than 63, + // since sin((k + y + 64*i) * pi/32) = sin(x + i * 2pi) = sin(x). + // + // When FMA instructions are not available, we store the digits of 32/pi in + // chunks of 28-bit precision. This will make sure that the products: + // x * THIRTYTWO_OVER_PI_28[i] are all exact. + // When FMA instructions are available, we simply store the digits of 32/pi in + // chunks of doubles (53-bit of precision). + // So when multiplying by the largest values of single precision, the + // resulting output should be correct up to 2^(-208 + 128) ~ 2^-80. By the + // worst-case analysis of range reduction, |y| >= 2^-38, so this should give + // us more than 40 bits of accuracy. For the worst-case estimation of range + // reduction, see for instances: + // Elementary Functions by J-M. Muller, Chapter 11, + // Handbook of Floating-Point Arithmetic by J-M. Muller et. al., + // Chapter 10.2. + // + // Once k and y are computed, we then deduce the answer by the sine of sum + // formula: + // sin(x) = sin((k + y)*pi/32) + // = sin(y*pi/32) * cos(k*pi/32) + cos(y*pi/32) * sin(k*pi/32) + // The values of sin(k*pi/32) and cos(k*pi/32) for k = 0..31 are precomputed + // and stored using a vector of 32 doubles. Sin(y*pi/32) and cos(y*pi/32) are + // computed using degree-7 and degree-6 minimax polynomials generated by + // Sollya respectively. + + // |x| <= pi/16 + if (LIBC_UNLIKELY(x_abs <= 0x3e49'0fdbU)) { + + // |x| < 0x1.d12ed2p-12f + if (LIBC_UNLIKELY(x_abs < 0x39e8'9769U)) { + if (LIBC_UNLIKELY(x_abs == 0U)) { + // For signed zeros. + return x; + } + // When |x| < 2^-12, the relative error of the approximation sin(x) ~ x + // is: + // |sin(x) - x| / |sin(x)| < |x^3| / (6|x|) + // = x^2 / 6 + // < 2^-25 + // < epsilon(1)/2. + // So the correctly rounded values of sin(x) are: + // = x - sign(x)*eps(x) if rounding mode = FE_TOWARDZERO, + // or (rounding mode = FE_UPWARD and x is + // negative), + // = x otherwise. + // To simplify the rounding decision and make it more efficient, we use + // fma(x, -2^-25, x) instead. + // An exhaustive test shows that this formula work correctly for all + // rounding modes up to |x| < 0x1.c555dep-11f. + // Note: to use the formula x - 2^-25*x to decide the correct rounding, we + // do need fma(x, -2^-25, x) to prevent underflow caused by -2^-25*x when + // |x| < 2^-125. For targets without FMA instructions, we simply use + // double for intermediate results as it is more efficient than using an + // emulated version of FMA. +#if defined(LIBC_TARGET_CPU_HAS_FMA_FLOAT) + return fputil::multiply_add(x, -0x1.0p-25f, x); +#else + return static_cast(fputil::multiply_add(xd, -0x1.0p-25, xd)); +#endif // LIBC_TARGET_CPU_HAS_FMA_FLOAT + } + + // |x| < pi/16. + double xsq = xd * xd; + + // Degree-9 polynomial approximation: + // sin(x) ~ x + a_3 x^3 + a_5 x^5 + a_7 x^7 + a_9 x^9 + // = x (1 + a_3 x^2 + ... + a_9 x^8) + // = x * P(x^2) + // generated by Sollya with the following commands: + // > display = hexadecimal; + // > Q = fpminimax(sin(x)/x, [|0, 2, 4, 6, 8|], [|1, D...|], [0, pi/16]); + double result = + fputil::polyeval(xsq, 1.0, -0x1.55555555554c6p-3, 0x1.1111111085e65p-7, + -0x1.a019f70fb4d4fp-13, 0x1.718d179815e74p-19); + return static_cast(xd * result); + } + +#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS + if (LIBC_UNLIKELY(x_abs == 0x4619'9998U)) { // x = 0x1.33333p13 + float r = -0x1.63f4bap-2f; + int rounding = fputil::quick_get_round(); + if ((rounding == FE_DOWNWARD && xbits.is_pos()) || + (rounding == FE_UPWARD && xbits.is_neg())) + r = -0x1.63f4bcp-2f; + return xbits.is_neg() ? -r : r; + } +#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS + + if (LIBC_UNLIKELY(x_abs >= 0x7f80'0000U)) { + if (xbits.is_signaling_nan()) { + fputil::raise_except_if_required(FE_INVALID); + return FPBits::quiet_nan().get_val(); + } + + if (x_abs == 0x7f80'0000U) { + fputil::set_errno_if_required(EDOM); + fputil::raise_except_if_required(FE_INVALID); + } + return x + FPBits::quiet_nan().get_val(); + } + + // Combine the results with the sine of sum formula: + // sin(x) = sin((k + y)*pi/32) + // = sin(y*pi/32) * cos(k*pi/32) + cos(y*pi/32) * sin(k*pi/32) + // = sin_y * cos_k + (1 + cosm1_y) * sin_k + // = sin_y * cos_k + (cosm1_y * sin_k + sin_k) + double sin_k, cos_k, sin_y, cosm1_y; + + sincosf_eval(xd, x_abs, sin_k, cos_k, sin_y, cosm1_y); + + return static_cast(fputil::multiply_add( + sin_y, cos_k, fputil::multiply_add(cosm1_y, sin_k, sin_k))); +} + +} // namespace math + +} // namespace LIBC_NAMESPACE_DECL + +#endif // LIBC_MATH_HAS_INTERMEDIATE_COMP_IN_FLOAT + +#endif // LLVM_LIBC_SRC___SUPPORT_MATH_SINF_H diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt index 3addfab6c6603..d07ef01567d6f 100644 --- a/libc/src/math/generic/CMakeLists.txt +++ b/libc/src/math/generic/CMakeLists.txt @@ -372,16 +372,8 @@ add_entrypoint_object( HDRS ../sinf.h DEPENDS - libc.src.__support.math.range_reduction - libc.src.__support.math.sincosf_utils + libc.src.__support.math.sinf libc.src.errno.errno - libc.src.__support.FPUtil.basic_operations - libc.src.__support.FPUtil.fenv_impl - libc.src.__support.FPUtil.fp_bits - libc.src.__support.FPUtil.fma - libc.src.__support.FPUtil.polyeval - libc.src.__support.FPUtil.rounding_mode - libc.src.__support.macros.optimization ) add_entrypoint_object( diff --git a/libc/src/math/generic/sinf.cpp b/libc/src/math/generic/sinf.cpp index c362628fb106c..648d57b82488c 100644 --- a/libc/src/math/generic/sinf.cpp +++ b/libc/src/math/generic/sinf.cpp @@ -7,176 +7,10 @@ //===----------------------------------------------------------------------===// #include "src/math/sinf.h" -#include "src/__support/FPUtil/BasicOperations.h" -#include "src/__support/FPUtil/FEnvImpl.h" -#include "src/__support/FPUtil/FPBits.h" -#include "src/__support/FPUtil/PolyEval.h" -#include "src/__support/FPUtil/multiply_add.h" -#include "src/__support/FPUtil/rounding_mode.h" -#include "src/__support/common.h" -#include "src/__support/macros/config.h" -#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY -#include "src/__support/macros/properties/cpu_features.h" // LIBC_TARGET_CPU_HAS_FMA - -#if defined(LIBC_MATH_HAS_SKIP_ACCURATE_PASS) && \ - defined(LIBC_MATH_HAS_INTERMEDIATE_COMP_IN_FLOAT) && \ - defined(LIBC_TARGET_CPU_HAS_FMA_FLOAT) - -#include "src/__support/math/sincosf_float_eval.h" +#include "src/__support/math/sinf.h" namespace LIBC_NAMESPACE_DECL { -LLVM_LIBC_FUNCTION(float, sinf, (float x)) { - return math::sincosf_float_eval::sincosf_eval(x); -} - -} // namespace LIBC_NAMESPACE_DECL - -#else // !LIBC_MATH_HAS_INTERMEDIATE_COMP_IN_FLOAT - -#include "src/__support/math/sincosf_utils.h" - -#ifdef LIBC_TARGET_CPU_HAS_FMA_DOUBLE -#include "src/__support/math/range_reduction_fma.h" -#else // !LIBC_TARGET_CPU_HAS_FMA_DOUBLE -#include "src/__support/math/range_reduction.h" -#endif // LIBC_TARGET_CPU_HAS_FMA_DOUBLE - -namespace LIBC_NAMESPACE_DECL { - -LLVM_LIBC_FUNCTION(float, sinf, (float x)) { - using FPBits = typename fputil::FPBits; - FPBits xbits(x); - - uint32_t x_u = xbits.uintval(); - uint32_t x_abs = x_u & 0x7fff'ffffU; - double xd = static_cast(x); - - // Range reduction: - // For |x| > pi/32, we perform range reduction as follows: - // Find k and y such that: - // x = (k + y) * pi/32 - // k is an integer - // |y| < 0.5 - // For small range (|x| < 2^45 when FMA instructions are available, 2^22 - // otherwise), this is done by performing: - // k = round(x * 32/pi) - // y = x * 32/pi - k - // For large range, we will omit all the higher parts of 32/pi such that the - // least significant bits of their full products with x are larger than 63, - // since sin((k + y + 64*i) * pi/32) = sin(x + i * 2pi) = sin(x). - // - // When FMA instructions are not available, we store the digits of 32/pi in - // chunks of 28-bit precision. This will make sure that the products: - // x * THIRTYTWO_OVER_PI_28[i] are all exact. - // When FMA instructions are available, we simply store the digits of 32/pi in - // chunks of doubles (53-bit of precision). - // So when multiplying by the largest values of single precision, the - // resulting output should be correct up to 2^(-208 + 128) ~ 2^-80. By the - // worst-case analysis of range reduction, |y| >= 2^-38, so this should give - // us more than 40 bits of accuracy. For the worst-case estimation of range - // reduction, see for instances: - // Elementary Functions by J-M. Muller, Chapter 11, - // Handbook of Floating-Point Arithmetic by J-M. Muller et. al., - // Chapter 10.2. - // - // Once k and y are computed, we then deduce the answer by the sine of sum - // formula: - // sin(x) = sin((k + y)*pi/32) - // = sin(y*pi/32) * cos(k*pi/32) + cos(y*pi/32) * sin(k*pi/32) - // The values of sin(k*pi/32) and cos(k*pi/32) for k = 0..31 are precomputed - // and stored using a vector of 32 doubles. Sin(y*pi/32) and cos(y*pi/32) are - // computed using degree-7 and degree-6 minimax polynomials generated by - // Sollya respectively. - - // |x| <= pi/16 - if (LIBC_UNLIKELY(x_abs <= 0x3e49'0fdbU)) { - - // |x| < 0x1.d12ed2p-12f - if (LIBC_UNLIKELY(x_abs < 0x39e8'9769U)) { - if (LIBC_UNLIKELY(x_abs == 0U)) { - // For signed zeros. - return x; - } - // When |x| < 2^-12, the relative error of the approximation sin(x) ~ x - // is: - // |sin(x) - x| / |sin(x)| < |x^3| / (6|x|) - // = x^2 / 6 - // < 2^-25 - // < epsilon(1)/2. - // So the correctly rounded values of sin(x) are: - // = x - sign(x)*eps(x) if rounding mode = FE_TOWARDZERO, - // or (rounding mode = FE_UPWARD and x is - // negative), - // = x otherwise. - // To simplify the rounding decision and make it more efficient, we use - // fma(x, -2^-25, x) instead. - // An exhaustive test shows that this formula work correctly for all - // rounding modes up to |x| < 0x1.c555dep-11f. - // Note: to use the formula x - 2^-25*x to decide the correct rounding, we - // do need fma(x, -2^-25, x) to prevent underflow caused by -2^-25*x when - // |x| < 2^-125. For targets without FMA instructions, we simply use - // double for intermediate results as it is more efficient than using an - // emulated version of FMA. -#if defined(LIBC_TARGET_CPU_HAS_FMA_FLOAT) - return fputil::multiply_add(x, -0x1.0p-25f, x); -#else - return static_cast(fputil::multiply_add(xd, -0x1.0p-25, xd)); -#endif // LIBC_TARGET_CPU_HAS_FMA_FLOAT - } - - // |x| < pi/16. - double xsq = xd * xd; - - // Degree-9 polynomial approximation: - // sin(x) ~ x + a_3 x^3 + a_5 x^5 + a_7 x^7 + a_9 x^9 - // = x (1 + a_3 x^2 + ... + a_9 x^8) - // = x * P(x^2) - // generated by Sollya with the following commands: - // > display = hexadecimal; - // > Q = fpminimax(sin(x)/x, [|0, 2, 4, 6, 8|], [|1, D...|], [0, pi/16]); - double result = - fputil::polyeval(xsq, 1.0, -0x1.55555555554c6p-3, 0x1.1111111085e65p-7, - -0x1.a019f70fb4d4fp-13, 0x1.718d179815e74p-19); - return static_cast(xd * result); - } - -#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS - if (LIBC_UNLIKELY(x_abs == 0x4619'9998U)) { // x = 0x1.33333p13 - float r = -0x1.63f4bap-2f; - int rounding = fputil::quick_get_round(); - if ((rounding == FE_DOWNWARD && xbits.is_pos()) || - (rounding == FE_UPWARD && xbits.is_neg())) - r = -0x1.63f4bcp-2f; - return xbits.is_neg() ? -r : r; - } -#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS - - if (LIBC_UNLIKELY(x_abs >= 0x7f80'0000U)) { - if (xbits.is_signaling_nan()) { - fputil::raise_except_if_required(FE_INVALID); - return FPBits::quiet_nan().get_val(); - } - - if (x_abs == 0x7f80'0000U) { - fputil::set_errno_if_required(EDOM); - fputil::raise_except_if_required(FE_INVALID); - } - return x + FPBits::quiet_nan().get_val(); - } - - // Combine the results with the sine of sum formula: - // sin(x) = sin((k + y)*pi/32) - // = sin(y*pi/32) * cos(k*pi/32) + cos(y*pi/32) * sin(k*pi/32) - // = sin_y * cos_k + (1 + cosm1_y) * sin_k - // = sin_y * cos_k + (cosm1_y * sin_k + sin_k) - double sin_k, cos_k, sin_y, cosm1_y; - - sincosf_eval(xd, x_abs, sin_k, cos_k, sin_y, cosm1_y); - - return static_cast(fputil::multiply_add( - sin_y, cos_k, fputil::multiply_add(cosm1_y, sin_k, sin_k))); -} +LLVM_LIBC_FUNCTION(float, sinf, (float x)) { return math::sinf(x); } } // namespace LIBC_NAMESPACE_DECL -#endif // LIBC_MATH_HAS_INTERMEDIATE_COMP_IN_FLOAT diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt index dabf5f6b168cc..653d41b96d6a8 100644 --- a/libc/test/shared/CMakeLists.txt +++ b/libc/test/shared/CMakeLists.txt @@ -80,6 +80,7 @@ add_fp_unittest( libc.src.__support.math.rsqrtf libc.src.__support.math.rsqrtf16 libc.src.__support.math.sin + libc.src.__support.math.sinf libc.src.__support.math.tan libc.src.__support.math.tanf ) diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp index cd389c41cb7b2..4c107d786d3a7 100644 --- a/libc/test/shared/shared_math_test.cpp +++ b/libc/test/shared/shared_math_test.cpp @@ -89,6 +89,7 @@ TEST(LlvmLibcSharedMathTest, AllFloat) { EXPECT_EQ(long(0), LIBC_NAMESPACE::shared::llogbf(1.0f)); EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::logbf(1.0f)); EXPECT_FP_EQ(0x1p+0f, LIBC_NAMESPACE::shared::rsqrtf(1.0f)); + EXPECT_FP_EQ(0.0f, LIBC_NAMESPACE::shared::sinf(0.0f)); EXPECT_FP_EQ(0.0f, LIBC_NAMESPACE::shared::tanf(0.0f)); } diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel index 346864d2276c0..66e87df60135d 100644 --- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel +++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel @@ -3455,6 +3455,20 @@ libc_support_library( ], ) +libc_support_library( + name = "__support_math_sinf", + hdrs = ["src/__support/math/sinf.h"], + deps = [ + ":__support_fputil_fma", + ":__support_fputil_polyeval", + ":__support_fputil_rounding_mode", + ":__support_macros_optimization", + ":__support_macros_properties_cpu_features", + ":__support_range_reduction", + ":__support_sincosf_utils", + ], +) + libc_support_library( name = "__support_math_sinhfcoshf_utils", hdrs = ["src/__support/math/sinhfcoshf_utils.h"], @@ -5058,13 +5072,7 @@ libc_math_function( libc_math_function( name = "sinf", additional_deps = [ - ":__support_fputil_fma", - ":__support_fputil_polyeval", - ":__support_fputil_rounding_mode", - ":__support_macros_optimization", - ":__support_macros_properties_cpu_features", - ":__support_range_reduction", - ":__support_sincosf_utils", + ":__support_math_sinf", ], )