[libc-commits] [libc] [libc][math][c23] Add tanpif16 function (PR #115183)
via libc-commits
libc-commits at lists.llvm.org
Wed Nov 6 09:14:43 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libc
Author: wldfngrs (wldfngrs)
<details>
<summary>Changes</summary>
- Implementation of `tan` for 16-bit floating point inputs scaled by pi. i.e,. `tanpif16()`
- Implementation of Tanpi in MPFRWrapper for MPFR versions < 4.2
- Exhaustive tests for `tanpif16()`
---
Full diff: https://github.com/llvm/llvm-project/pull/115183.diff
14 Files Affected:
- (modified) libc/config/linux/x86_64/entrypoints.txt (+1)
- (modified) libc/newhdrgen/yaml/math.yaml (+7)
- (modified) libc/src/math/CMakeLists.txt (+1)
- (modified) libc/src/math/cospif16.h (+1-1)
- (modified) libc/src/math/generic/CMakeLists.txt (+20)
- (modified) libc/src/math/generic/cospif16.cpp (+1-1)
- (added) libc/src/math/generic/tanpif16.cpp (+103)
- (added) libc/src/math/tanpif16.h (+21)
- (modified) libc/test/src/math/CMakeLists.txt (+11)
- (modified) libc/test/src/math/smoke/CMakeLists.txt (+11)
- (added) libc/test/src/math/smoke/tanpif16_test.cpp (+33)
- (added) libc/test/src/math/tanpif16_test.cpp (+40)
- (modified) libc/utils/MPFRWrapper/MPFRUtils.cpp (+50)
- (modified) libc/utils/MPFRWrapper/MPFRUtils.h (+1)
``````````diff
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index a2fb97d04584d5..1b850a6df60841 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -687,6 +687,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
libc.src.math.sinpif16
libc.src.math.sqrtf16
libc.src.math.tanhf16
+ libc.src.math.tanpif16
libc.src.math.totalorderf16
libc.src.math.totalordermagf16
libc.src.math.truncf16
diff --git a/libc/newhdrgen/yaml/math.yaml b/libc/newhdrgen/yaml/math.yaml
index 3cc4b599c777bf..07a0b80d6e4ccc 100644
--- a/libc/newhdrgen/yaml/math.yaml
+++ b/libc/newhdrgen/yaml/math.yaml
@@ -2410,6 +2410,13 @@ functions:
arguments:
- type: _Float16
guard: LIBC_TYPES_HAS_FLOAT16
+ - name: tanpif16
+ standards:
+ - stdc
+ return_type: _Float16
+ arguments:
+ - type: _Float16
+ guard: LIBC_TYPES_HAS_FLOAT16
- name: totalorder
standards:
- stdc
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 80c1867d2116f6..9f376193e0e740 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -502,6 +502,7 @@ add_math_entrypoint_object(tanf)
add_math_entrypoint_object(tanh)
add_math_entrypoint_object(tanhf)
add_math_entrypoint_object(tanhf16)
+add_math_entrypoint_object(tanpif16)
add_math_entrypoint_object(tgamma)
add_math_entrypoint_object(tgammaf)
diff --git a/libc/src/math/cospif16.h b/libc/src/math/cospif16.h
index ef9625dfed45f6..122b548dfb0983 100644
--- a/libc/src/math/cospif16.h
+++ b/libc/src/math/cospif16.h
@@ -18,4 +18,4 @@ float16 cospif16(float16 x);
} // namespace LIBC_NAMESPACE_DECL
-#endif // LLVM_LIBC_SRC_MATH_SINPIF16_H
+#endif // LLVM_LIBC_SRC_MATH_COSPIF16_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index ca27759d3212f2..ceb8f0df00129c 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -620,6 +620,26 @@ add_entrypoint_object(
-O3
)
+add_entrypoint_object(
+ tanpif16
+ SRCS
+ tanpif16.cpp
+ HDRS
+ ../tanpif16.h
+ DEPENDS
+ .sincosf16_utils
+ libc.hdr.errno_macros
+ libc.hdr.fenv_macros
+ libc.src.__support.FPUtil.cast
+ libc.src.__support.FPUtil.fenv_impl
+ libc.src.__support.FPUtil.fp_bits
+ libc.src.__support.FPUtil.except_value_utils
+ libc.src.__support.FPUtil.multiply_add
+ libc.src.__support.macros.optimization
+ COMPILE_OPTIONS
+ -O3
+)
+
add_entrypoint_object(
fabs
SRCS
diff --git a/libc/src/math/generic/cospif16.cpp b/libc/src/math/generic/cospif16.cpp
index dd8c7ab6afa3d6..384b39ff8e2c44 100644
--- a/libc/src/math/generic/cospif16.cpp
+++ b/libc/src/math/generic/cospif16.cpp
@@ -37,7 +37,7 @@ LLVM_LIBC_FUNCTION(float16, cospif16, (float16 x)) {
// k = round(x * 32)
// y = x * 32 - k
//
- // Once k and y are computed, we then deduce the answer by the sine of sum
+ // Once k and y are computed, we then deduce the answer by the cosine of sum
// formula:
// cos(x * pi) = cos((k + y) * pi/32)
// = cos(k * pi/32) * cos(y * pi/32) +
diff --git a/libc/src/math/generic/tanpif16.cpp b/libc/src/math/generic/tanpif16.cpp
new file mode 100644
index 00000000000000..450022f5992343
--- /dev/null
+++ b/libc/src/math/generic/tanpif16.cpp
@@ -0,0 +1,103 @@
+//===-- Half-precision tanpif 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/tanpif16.h"
+#include "hdr/errno_macros.h"
+#include "hdr/fenv_macros.h"
+#include "sincosf16_utils.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/cast.h"
+#include "src/__support/FPUtil/except_value_utils.h"
+#include "src/__support/FPUtil/multiply_add.h"
+#include "src/__support/macros/optimization.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+constexpr size_t N_EXCEPTS = 21;
+
+constexpr fputil::ExceptValues<float16, N_EXCEPTS> TANF16_EXCEPTS{{
+ // (input, RZ output, RU offset, RD offset, RN offset)
+ {0x07f2, 0x0e3d, 1, 0, 0}, {0x086a, 0x0eee, 1, 0, 1},
+ {0x08db, 0x0fa0, 1, 0, 0}, {0x094c, 0x1029, 1, 0, 0},
+ {0x0b10, 0x118c, 1, 0, 0}, {0x1ce0, 0x23a8, 1, 0, 1},
+ {0x1235, 0x18e0, 1, 0, 0}, {0x2579, 0x2c4e, 1, 0, 0},
+ {0x28b2, 0x2f68, 1, 0, 1}, {0x2a43, 0x30f4, 1, 0, 1},
+ {0x31b7, 0x3907, 1, 0, 0}, {0x329d, 0x3a12, 1, 0, 1},
+ {0x34f1, 0x3dd7, 1, 0, 0}, {0x3658, 0x41ee, 1, 0, 0},
+ {0x38d4, 0xc1ee, 0, 1, 0}, {0x3d96, 0x41ee, 1, 0, 0},
+ {0x3e6a, 0xc1ee, 0, 1, 0}, {0x40cb, 0x41ee, 1, 0, 0},
+ {0x4135, 0xc1ee, 0, 1, 0}, {0x42cb, 0x41ee, 1, 0, 0},
+ {0x4335, 0xc1ee, 0, 1, 0},
+}};
+
+LLVM_LIBC_FUNCTION(float16, tanpif16, (float16 x)) {
+ using FPBits = typename fputil::FPBits<float16>;
+ FPBits xbits(x);
+
+ uint16_t x_u = xbits.uintval();
+ bool x_sign = x_u >> 15;
+ uint16_t x_abs = x_u & 0x7fff;
+
+ if (LIBC_UNLIKELY(x_abs == 0U))
+ return x;
+
+ // Handle exceptional values
+ if (LIBC_UNLIKELY(x_abs <= 0x4335)) {
+ if (auto r = TANF16_EXCEPTS.lookup_odd(x_abs, x_sign);
+ LIBC_UNLIKELY(r.has_value()))
+ return r.value();
+ }
+
+ // Numbers greater or equal to 2^10 are integers, or infinity, or NaN
+ if (LIBC_UNLIKELY(x_abs >= 0x6400)) {
+ // Check for NaN or infinity values
+ if (LIBC_UNLIKELY(x_abs >= 0x7c00)) {
+ if (x_abs == 0x7c00) {
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_INVALID);
+ }
+
+ return x + FPBits::quiet_nan().get_val();
+ }
+
+ return FPBits::zero(xbits.sign()).get_val();
+ }
+ // Range reduction:
+ // For |x| > 1/32, we perform range reduction as follows:
+ // Find k and y such that:
+ // x = (k + y) * 1/32
+ // k is an integer
+ // |y| < 0.5
+ //
+ // This is done by performing:
+ // k = round(x * 32)
+ // y = x * 32 - k
+ //
+ // Once k and y are computed, we then deduce the answer by tthe formula:
+ // tan(x) = sin(x) / cos(x)
+ // = (sin_y * cos_k + cos_y * sin_k) / (cos_y * cos_k - sin_y * sin_k)
+ float xf = x;
+ float sin_k, cos_k, sin_y, cosm1_y;
+ sincospif16_eval(xf, sin_k, cos_k, sin_y, cosm1_y);
+
+ if (LIBC_UNLIKELY(sin_y == 0 && cos_k == 0)) {
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_DIVBYZERO);
+
+ int16_t x_mp5_u = static_cast<int16_t>(x - 0.5);
+ return ((x_mp5_u & 0x1) ? -1 : 1) * FPBits::inf().get_val();
+ }
+
+ using fputil::multiply_add;
+ return fputil::cast<float16>(
+ multiply_add(sin_y, cos_k, multiply_add(cosm1_y, sin_k, sin_k)) /
+ multiply_add(sin_y, -sin_k, multiply_add(cosm1_y, cos_k, cos_k)));
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/tanpif16.h b/libc/src/math/tanpif16.h
new file mode 100644
index 00000000000000..c07a955564de37
--- /dev/null
+++ b/libc/src/math/tanpif16.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for tanpif16 ----------------------*- 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_SRC_MATH_TANPIF16_H
+#define LLVM_LIBC_SRC_MATH_TANPIF16_H
+
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+float16 tanpif16(float16 x);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_MATH_TANPIF16_H
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index b46ef4028915ba..ebe98d346b8320 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -168,6 +168,17 @@ add_fp_unittest(
libc.src.__support.FPUtil.fp_bits
)
+add_fp_unittest(
+ tanpif16_test
+ NEED_MPFR
+ SUITE
+ libc-math-unittests
+ SRCS
+ tanpif16_test.cpp
+ DEPENDS
+ libc.src.math.tanpif16
+)
+
add_fp_unittest(
fabs_test
NEED_MPFR
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 269e92c5900628..8c75d1577081d0 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -99,6 +99,17 @@ add_fp_unittest(
libc.src.__support.FPUtil.fp_bits
)
+add_fp_unittest(
+ tanpif16_test
+ SUITE
+ libc-math-smoke-tests
+ SRCS
+ tanpif16_test.cpp
+ DEPENDS
+ libc.src.errno.errno
+ libc.src.math.tanpif16
+)
+
add_fp_unittest(
fabs_test
SUITE
diff --git a/libc/test/src/math/smoke/tanpif16_test.cpp b/libc/test/src/math/smoke/tanpif16_test.cpp
new file mode 100644
index 00000000000000..a378cfb0a62e1f
--- /dev/null
+++ b/libc/test/src/math/smoke/tanpif16_test.cpp
@@ -0,0 +1,33 @@
+//===-- Unittests for tanpif16 --------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/errno/libc_errno.h"
+#include "src/math/tanpif16.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using LlvmLibcTanpif16Test = LIBC_NAMESPACE::testing::FPTest<float16>;
+
+TEST_F(LlvmLibcTanpif16Test, SpecialNumbers) {
+ LIBC_NAMESPACE::libc_errno = 0;
+
+ EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::tanpif16(aNaN));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ(zero, LIBC_NAMESPACE::tanpif16(zero));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ(neg_zero, LIBC_NAMESPACE::tanpif16(neg_zero));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::tanpif16(inf));
+ EXPECT_MATH_ERRNO(EDOM);
+
+ EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::tanpif16(neg_inf));
+ EXPECT_MATH_ERRNO(EDOM);
+}
diff --git a/libc/test/src/math/tanpif16_test.cpp b/libc/test/src/math/tanpif16_test.cpp
new file mode 100644
index 00000000000000..629ba963135c06
--- /dev/null
+++ b/libc/test/src/math/tanpif16_test.cpp
@@ -0,0 +1,40 @@
+//===-- Exhaustive test for cospif16 --------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/tanpif16.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+using LlvmLibcTanpif16Test = LIBC_NAMESPACE::testing::FPTest<float16>;
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+// Range: [0, Inf]
+static constexpr uint16_t POS_START = 0x0000U;
+static constexpr uint16_t POS_STOP = 0x7c00U;
+
+// Range: [-Inf, 0]
+static constexpr uint16_t NEG_START = 0x8000U;
+static constexpr uint16_t NEG_STOP = 0xfc00U;
+
+TEST_F(LlvmLibcTanpif16Test, PositiveRange) {
+ for (uint16_t v = POS_START; v <= POS_STOP; ++v) {
+ float16 x = FPBits(v).get_val();
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Tanpi, x,
+ LIBC_NAMESPACE::tanpif16(x), 0.5);
+ }
+}
+
+TEST_F(LlvmLibcTanpif16Test, NegativeRange) {
+ for (uint16_t v = NEG_START; v <= NEG_STOP; ++v) {
+ float16 x = FPBits(v).get_val();
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Tanpi, x,
+ LIBC_NAMESPACE::tanpif16(x), 0.5);
+ }
+}
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.cpp b/libc/utils/MPFRWrapper/MPFRUtils.cpp
index 5afc3d007d4d7a..00ac8a8ba271ac 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.cpp
+++ b/libc/utils/MPFRWrapper/MPFRUtils.cpp
@@ -560,6 +560,54 @@ class MPFRNumber {
return result;
}
+ MPFRNumber tanpi() const {
+ MPFRNumber result(*this);
+
+#if MPFR_VERSION_MAJOR > 4 || \
+ (MPFR_VERSION_MAJOR == 4 && MPFR_VERSION_MINOR >= 2)
+
+ mpfr_tanpi(result.value, value, mpfr_rounding);
+ return result;
+#else
+ MPFRNumber value_ret_exact(*this);
+ mpfr_fmod_ui(value_ret_exact.value, value, 1, mpfr_rounding);
+ mpfr_mul_si(value_ret_exact.value, value_ret_exact.value, 4, MPFR_RNDN);
+
+ if (mpfr_integer_p(value_ret_exact.value)) {
+ int mod = mpfr_get_si(value_ret_exact.value, MPFR_RNDN);
+ mod = (mod < 0 ? -1 * mod : mod);
+
+ switch (mod) {
+ case 0:
+ mpfr_set_si(result.value, 0, mpfr_rounding);
+ break;
+ case 1:
+ mpfr_set_si(result.value, (mpfr_signbit(value) ? -1 : 1),
+ mpfr_rounding);
+ break;
+ case 2: {
+ auto d = mpfr_get_si(value, MPFR_RNDZ);
+ d += mpfr_sgn(value) > 0 ? 0 : 1;
+ mpfr_set_inf(result.value, (d & 1) ? -1 : 1);
+ break;
+ }
+ case 3:
+ mpfr_set_si(result.value, (mpfr_signbit(value) ? 1 : -1),
+ mpfr_rounding);
+ break;
+ }
+
+ return result;
+ }
+
+ MPFRNumber value_pi(0.0, 1280);
+ mpfr_const_pi(value_pi.value, MPFR_RNDN);
+ mpfr_mul(value_pi.value, value_pi.value, value, MPFR_RNDN);
+ mpfr_tan(result.value, value_pi.value, mpfr_rounding);
+ return result;
+#endif
+ }
+
MPFRNumber trunc() const {
MPFRNumber result(*this);
mpfr_trunc(result.value, value);
@@ -798,6 +846,8 @@ unary_operation(Operation op, InputType input, unsigned int precision,
return mpfrInput.tan();
case Operation::Tanh:
return mpfrInput.tanh();
+ case Operation::Tanpi:
+ return mpfrInput.tanpi();
case Operation::Trunc:
return mpfrInput.trunc();
default:
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.h b/libc/utils/MPFRWrapper/MPFRUtils.h
index 9fc12a6adefb56..c7a57819f68b79 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.h
+++ b/libc/utils/MPFRWrapper/MPFRUtils.h
@@ -60,6 +60,7 @@ enum class Operation : int {
Sqrt,
Tan,
Tanh,
+ Tanpi,
Trunc,
EndUnaryOperationsSingleOutput,
``````````
</details>
https://github.com/llvm/llvm-project/pull/115183
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