[llvm-branch-commits] [libc] [libc][math][c23] Add logf16 C23 math function (PR #106072)
via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Thu Oct 17 11:50:29 PDT 2024
https://github.com/overmighty updated https://github.com/llvm/llvm-project/pull/106072
>From f011fa727e0974dc3ec69ecd8b5860008efa524d Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Mon, 26 Aug 2024 15:30:54 +0200
Subject: [PATCH 1/4] [libc][math][c23] Add logf16 C23 math function
Part of #95250.
---
libc/config/gpu/entrypoints.txt | 1 +
libc/config/linux/x86_64/entrypoints.txt | 1 +
libc/docs/math/index.rst | 2 +-
libc/spec/stdc.td | 1 +
libc/src/math/CMakeLists.txt | 1 +
libc/src/math/generic/CMakeLists.txt | 22 ++++
libc/src/math/generic/expxf16.h | 26 ++++
libc/src/math/generic/logf16.cpp | 158 +++++++++++++++++++++++
libc/src/math/logf16.h | 21 +++
libc/test/UnitTest/FPMatcher.h | 13 ++
libc/test/src/math/CMakeLists.txt | 11 ++
libc/test/src/math/logf16_test.cpp | 40 ++++++
libc/test/src/math/smoke/CMakeLists.txt | 12 ++
libc/test/src/math/smoke/logf16_test.cpp | 47 +++++++
14 files changed, 355 insertions(+), 1 deletion(-)
create mode 100644 libc/src/math/generic/logf16.cpp
create mode 100644 libc/src/math/logf16.h
create mode 100644 libc/test/src/math/logf16_test.cpp
create mode 100644 libc/test/src/math/smoke/logf16_test.cpp
diff --git a/libc/config/gpu/entrypoints.txt b/libc/config/gpu/entrypoints.txt
index d89093b2117c2d..d9df737efea3d7 100644
--- a/libc/config/gpu/entrypoints.txt
+++ b/libc/config/gpu/entrypoints.txt
@@ -568,6 +568,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
libc.src.math.llrintf16
libc.src.math.llroundf16
libc.src.math.logbf16
+ libc.src.math.logf16
libc.src.math.lrintf16
libc.src.math.lroundf16
libc.src.math.modff16
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 7314dbc660f3cb..3d9d5a9e984c3d 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -661,6 +661,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
libc.src.math.llrintf16
libc.src.math.llroundf16
libc.src.math.logbf16
+ libc.src.math.logf16
libc.src.math.lrintf16
libc.src.math.lroundf16
libc.src.math.modff16
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 010377a90f6eac..a4c59190a01bcd 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -310,7 +310,7 @@ Higher Math Functions
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
| lgamma | | | | | | 7.12.8.3 | F.10.5.3 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| log | |check| | |check| | | | | 7.12.6.11 | F.10.3.11 |
+| log | |check| | |check| | | |check| | | 7.12.6.11 | F.10.3.11 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
| log10 | |check| | |check| | | | | 7.12.6.12 | F.10.3.12 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 196dab9f81b38e..cc49835ac7e125 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -651,6 +651,7 @@ def StdC : StandardSpec<"stdc"> {
FunctionSpec<"log", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
FunctionSpec<"logf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+ GuardedFunctionSpec<"logf16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
FunctionSpec<"logb", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
FunctionSpec<"logbf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 8427b550ab4c7c..9c6646cd658ed7 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -343,6 +343,7 @@ add_math_entrypoint_object(log2f)
add_math_entrypoint_object(log)
add_math_entrypoint_object(logf)
+add_math_entrypoint_object(logf16)
add_math_entrypoint_object(logb)
add_math_entrypoint_object(logbf)
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 81b3e44db7923e..e7582c1939c760 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -2289,6 +2289,28 @@ add_entrypoint_object(
-O3
)
+add_entrypoint_object(
+ logf16
+ SRCS
+ logf16.cpp
+ HDRS
+ ../logf16.h
+ DEPENDS
+ .expxf16
+ libc.hdr.errno_macros
+ libc.hdr.fenv_macros
+ libc.src.__support.CPP.array
+ libc.src.__support.FPUtil.except_value_utils
+ libc.src.__support.FPUtil.fenv_impl
+ libc.src.__support.FPUtil.fp_bits
+ libc.src.__support.FPUtil.multiply_add
+ libc.src.__support.FPUtil.polyeval
+ libc.src.__support.macros.optimization
+ libc.src.__support.macros.properties.cpu_features
+ COMPILE_OPTIONS
+ -O3
+)
+
add_entrypoint_object(
logb
SRCS
diff --git a/libc/src/math/generic/expxf16.h b/libc/src/math/generic/expxf16.h
index 7202b1b113190e..cb73f6c180c600 100644
--- a/libc/src/math/generic/expxf16.h
+++ b/libc/src/math/generic/expxf16.h
@@ -288,6 +288,32 @@ template <bool IsSinh> LIBC_INLINE float16 eval_sinh_or_cosh(float16 x) {
lo, half_p_odd * exp2_hi_mid_diff, half_p_even * exp2_hi_mid_sum));
}
+// Generated by Sollya with the following commands:
+// > display = hexadecimal;
+// > for i from 0 to 31 do print(round(log(1 + i * 2^-5), SG, RN));
+constexpr cpp::array<float, 32> LOGF_F = {
+ 0x0p+0, 0x1.f829bp-6, 0x1.f0a30cp-5, 0x1.6f0d28p-4, 0x1.e27076p-4,
+ 0x1.29553p-3, 0x1.5ff308p-3, 0x1.9525aap-3, 0x1.c8ff7cp-3, 0x1.fb9186p-3,
+ 0x1.1675cap-2, 0x1.2e8e2cp-2, 0x1.4618bcp-2, 0x1.5d1bdcp-2, 0x1.739d8p-2,
+ 0x1.89a338p-2, 0x1.9f323ep-2, 0x1.b44f78p-2, 0x1.c8ff7cp-2, 0x1.dd46ap-2,
+ 0x1.f128f6p-2, 0x1.02552ap-1, 0x1.0be72ep-1, 0x1.154c3ep-1, 0x1.1e85f6p-1,
+ 0x1.2795e2p-1, 0x1.307d74p-1, 0x1.393e0ep-1, 0x1.41d8fep-1, 0x1.4a4f86p-1,
+ 0x1.52a2d2p-1, 0x1.5ad404p-1,
+};
+
+// Generated by Sollya with the following commands:
+// > display = hexadecimal;
+// > for i from 0 to 31 do print(round(1 / (1 + i * 2^-5), SG, RN));
+constexpr cpp::array<float, 32> ONE_OVER_F = {
+ 0x1p+0, 0x1.f07c2p-1, 0x1.e1e1e2p-1, 0x1.d41d42p-1, 0x1.c71c72p-1,
+ 0x1.bacf92p-1, 0x1.af286cp-1, 0x1.a41a42p-1, 0x1.99999ap-1, 0x1.8f9c18p-1,
+ 0x1.861862p-1, 0x1.7d05f4p-1, 0x1.745d18p-1, 0x1.6c16c2p-1, 0x1.642c86p-1,
+ 0x1.5c9882p-1, 0x1.555556p-1, 0x1.4e5e0ap-1, 0x1.47ae14p-1, 0x1.414142p-1,
+ 0x1.3b13b2p-1, 0x1.3521dp-1, 0x1.2f684cp-1, 0x1.29e412p-1, 0x1.24924ap-1,
+ 0x1.1f7048p-1, 0x1.1a7b96p-1, 0x1.15b1e6p-1, 0x1.111112p-1, 0x1.0c9714p-1,
+ 0x1.08421p-1, 0x1.041042p-1,
+};
+
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC_MATH_GENERIC_EXPXF16_H
diff --git a/libc/src/math/generic/logf16.cpp b/libc/src/math/generic/logf16.cpp
new file mode 100644
index 00000000000000..adb24306a0f466
--- /dev/null
+++ b/libc/src/math/generic/logf16.cpp
@@ -0,0 +1,158 @@
+//===-- Half-precision log(x) 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/logf16.h"
+#include "expxf16.h"
+#include "hdr/errno_macros.h"
+#include "hdr/fenv_macros.h"
+#include "src/__support/CPP/array.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/PolyEval.h"
+#include "src/__support/FPUtil/except_value_utils.h"
+#include "src/__support/FPUtil/multiply_add.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/optimization.h"
+#include "src/__support/macros/properties/cpu_features.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+#ifdef LIBC_TARGET_CPU_HAS_FMA
+static constexpr size_t N_LOGF16_EXCEPTS = 5;
+#else
+static constexpr size_t N_LOGF16_EXCEPTS = 11;
+#endif
+
+static constexpr fputil::ExceptValues<float16, N_LOGF16_EXCEPTS>
+ LOGF16_EXCEPTS = {{
+// (input, RZ output, RU offset, RD offset, RN offset)
+#ifndef LIBC_TARGET_CPU_HAS_FMA
+ // x = 0x1.61cp-13, logf16(x) = -0x1.16p+3 (RZ)
+ {0x0987U, 0xc858U, 0U, 1U, 0U},
+ // x = 0x1.f2p-12, logf16(x) = -0x1.e98p+2 (RZ)
+ {0x0fc8U, 0xc7a6U, 0U, 1U, 1U},
+// x = 0x1.4d4p-9, logf16(x) = -0x1.7e4p+2 (RZ)
+#endif
+ // x = 0x1.4d4p-9, logf16(x) = -0x1.7e4p+2 (RZ)
+ {0x1935U, 0xc5f9U, 0U, 1U, 0U},
+ // x = 0x1.5ep-8, logf16(x) = -0x1.4ecp+2 (RZ)
+ {0x1d78U, 0xc53bU, 0U, 1U, 0U},
+#ifndef LIBC_TARGET_CPU_HAS_FMA
+ // x = 0x1.fdp-1, logf16(x) = -0x1.81p-8 (RZ)
+ {0x3bf4U, 0x9e04U, 0U, 1U, 1U},
+ // x = 0x1.fep-1, logf16(x) = -0x1.008p-8 (RZ)
+ {0x3bf8U, 0x9c02U, 0U, 1U, 0U},
+#endif
+ // x = 0x1.ffp-1, logf16(x) = -0x1.004p-9 (RZ)
+ {0x3bfcU, 0x9801U, 0U, 1U, 0U},
+ // x = 0x1.ff8p-1, logf16(x) = -0x1p-10 (RZ)
+ {0x3bfeU, 0x9400U, 0U, 1U, 1U},
+#ifdef LIBC_TARGET_CPU_HAS_FMA
+ // x = 0x1.4c4p+1, logf16(x) = 0x1.e84p-1 (RZ)
+ {0x4131U, 0x3ba1U, 1U, 0U, 1U},
+#else
+ // x = 0x1.75p+2, logf16(x) = 0x1.c34p+0 (RZ)
+ {0x45d4U, 0x3f0dU, 1U, 0U, 0U},
+ // x = 0x1.75p+2, logf16(x) = 0x1.c34p+0 (RZ)
+ {0x45d4U, 0x3f0dU, 1U, 0U, 0U},
+ // x = 0x1.d5p+9, logf16(x) = 0x1.b5cp+2 (RZ)
+ {0x6354U, 0x46d7U, 1U, 0U, 1U},
+#endif
+ }};
+
+LLVM_LIBC_FUNCTION(float16, logf16, (float16 x)) {
+ using FPBits = fputil::FPBits<float16>;
+ FPBits x_bits(x);
+
+ uint16_t x_u = x_bits.uintval();
+
+ // If x <= 0, or x is 1, or x is +inf, or x is NaN.
+ if (LIBC_UNLIKELY(x_u == 0U || x_u == 0x3c00U || x_u >= 0x7c00U)) {
+ // log(NaN) = NaN
+ if (x_bits.is_nan()) {
+ if (x_bits.is_signaling_nan()) {
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+
+ return x;
+ }
+
+ // log(+/-0) = −inf
+ if ((x_u & 0x7fffU) == 0U) {
+ fputil::raise_except_if_required(FE_DIVBYZERO);
+ return FPBits::inf(Sign::NEG).get_val();
+ }
+
+ if (x_u == 0x3c00U)
+ return FPBits::zero().get_val();
+
+ // When x < 0.
+ if (x_u > 0x8000) {
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+
+ // log(+inf) = +inf
+ return FPBits::inf().get_val();
+ }
+
+ if (auto r = LOGF16_EXCEPTS.lookup(x_u); LIBC_UNLIKELY(r.has_value()))
+ return r.value();
+
+ // To compute log(x), we perform the following range reduction:
+ // x = 2^m * 1.mant,
+ // log(x) = m * log(2) + log(1.mant).
+ // To compute log(1.mant), let f be the highest 6 bits including the hidden
+ // bit, and d be the difference (1.mant - f), i.e., the remaining 5 bits of
+ // the mantissa, then:
+ // log(1.mant) = log(f) + log(1.mant / f)
+ // = log(f) + log(1 + d/f)
+ // since d/f is sufficiently small.
+ // We store log(f) and 1/f in the lookup tables LOGF_F and ONE_OVER_F
+ // respectively.
+
+ int m = -FPBits::EXP_BIAS;
+
+ // When x is subnormal.
+ if ((x_u & FPBits::EXP_MASK) == 0U) {
+ // Normalize x.
+ x_bits = FPBits(x_bits.get_val() *
+ static_cast<float16>((1U << FPBits::FRACTION_LEN)));
+ x_u = x_bits.uintval();
+ m -= FPBits::FRACTION_LEN;
+ }
+
+ uint16_t mant = x_bits.get_mantissa();
+ // Leading 10 - 5 = 5 bits of the mantissa.
+ int f = mant >> 5;
+ // Unbiased exponent.
+ m += x_u >> FPBits::FRACTION_LEN;
+
+ // Set bits to 1.mant instead of 2^m * 1.mant.
+ x_bits.set_biased_exponent(FPBits::EXP_BIAS);
+ float mant_f = x_bits.get_val();
+ // v = 1.mant * 1/f - 1 = d/f
+ float v = fputil::multiply_add(mant_f, ONE_OVER_F[f], -1.0f);
+
+ // Degree-3 minimax polynomial generated by Sollya with the following
+ // commands:
+ // > display = hexadecimal;
+ // > P = fpminimax(log(1 + x)/x, 2, [|SG...|], [-2^-5, 2^-5]);
+ // > x * P;
+ float log1p_d_over_f =
+ v * fputil::polyeval(v, 0x1p+0f, -0x1.001804p-1f, 0x1.557ef6p-2f);
+ // log(1.mant) = log(f) + log(1 + d/f)
+ float log_1_mant = LOGF_F[f] + log1p_d_over_f;
+ return static_cast<float16>(
+ fputil::multiply_add(static_cast<float>(m), LOGF_2, log_1_mant));
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/logf16.h b/libc/src/math/logf16.h
new file mode 100644
index 00000000000000..e2d296b1d90881
--- /dev/null
+++ b/libc/src/math/logf16.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for logf16 ------------------------*- 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_LOGF16_H
+#define LLVM_LIBC_SRC_MATH_LOGF16_H
+
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+float16 logf16(float16 x);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_MATH_LOGF16_H
diff --git a/libc/test/UnitTest/FPMatcher.h b/libc/test/UnitTest/FPMatcher.h
index 5220b1245bf3a5..03b636937a71b8 100644
--- a/libc/test/UnitTest/FPMatcher.h
+++ b/libc/test/UnitTest/FPMatcher.h
@@ -357,4 +357,17 @@ template <typename T> struct FPTest : public Test {
EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_MODE( \
(expected), (actual), (expected_except), RoundingMode::TowardZero)
+#define EXPECT_FP_EQ_WITH_EXCEPTION_ALL_ROUNDING(expected, actual, \
+ expected_except) \
+ do { \
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_NEAREST((expected), (actual), \
+ (expected_except)); \
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_UPWARD((expected), (actual), \
+ (expected_except)); \
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_DOWNWARD((expected), (actual), \
+ (expected_except)); \
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_TOWARD_ZERO((expected), (actual), \
+ (expected_except)); \
+ } while (0)
+
#endif // LLVM_LIBC_TEST_UNITTEST_FPMATCHER_H
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 11342e6dfa0452..2d935f58848828 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1772,6 +1772,17 @@ add_fp_unittest(
libc.src.__support.FPUtil.fp_bits
)
+add_fp_unittest(
+ logf16_test
+ NEED_MPFR
+ SUITE
+ libc-math-unittests
+ SRCS
+ logf16_test.cpp
+ DEPENDS
+ libc.src.math.logf16
+)
+
add_fp_unittest(
log2_test
NEED_MPFR
diff --git a/libc/test/src/math/logf16_test.cpp b/libc/test/src/math/logf16_test.cpp
new file mode 100644
index 00000000000000..67e5e172e53b8c
--- /dev/null
+++ b/libc/test/src/math/logf16_test.cpp
@@ -0,0 +1,40 @@
+//===-- Exhaustive test for logf16 ---------------------------------------===//
+//
+// 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/logf16.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+using LlvmLibcLogf16Test = 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(LlvmLibcLogf16Test, PositiveRange) {
+ for (uint16_t v = POS_START; v <= POS_STOP; ++v) {
+ float16 x = FPBits(v).get_val();
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log, x,
+ LIBC_NAMESPACE::logf16(x), 0.5);
+ }
+}
+
+TEST_F(LlvmLibcLogf16Test, NegativeRange) {
+ for (uint16_t v = NEG_START; v <= NEG_STOP; ++v) {
+ float16 x = FPBits(v).get_val();
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log, x,
+ LIBC_NAMESPACE::logf16(x), 0.5);
+ }
+}
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 899c9d2df45306..a1ccd261f97abb 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3558,6 +3558,18 @@ add_fp_unittest(
libc.src.__support.FPUtil.fp_bits
)
+add_fp_unittest(
+ logf16_test
+ SUITE
+ libc-math-smoke-tests
+ SRCS
+ logf16_test.cpp
+ DEPENDS
+ libc.hdr.fenv_macros
+ libc.src.errno.errno
+ libc.src.math.logf16
+)
+
add_fp_unittest(
log2_test
SUITE
diff --git a/libc/test/src/math/smoke/logf16_test.cpp b/libc/test/src/math/smoke/logf16_test.cpp
new file mode 100644
index 00000000000000..e2f21003e8d81b
--- /dev/null
+++ b/libc/test/src/math/smoke/logf16_test.cpp
@@ -0,0 +1,47 @@
+//===-- Unittests for logf16 ----------------------------------------------===//
+//
+// 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 "hdr/fenv_macros.h"
+#include "src/errno/libc_errno.h"
+#include "src/math/logf16.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using LlvmLibcLogf16Test = LIBC_NAMESPACE::testing::FPTest<float16>;
+
+TEST_F(LlvmLibcLogf16Test, SpecialNumbers) {
+ LIBC_NAMESPACE::libc_errno = 0;
+
+ EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::logf16(aNaN));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION(aNaN, LIBC_NAMESPACE::logf16(sNaN), FE_INVALID);
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(inf, LIBC_NAMESPACE::logf16(inf));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::logf16(neg_inf));
+ EXPECT_MATH_ERRNO(EDOM);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ALL_ROUNDING(
+ neg_inf, LIBC_NAMESPACE::logf16(zero), FE_DIVBYZERO);
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ALL_ROUNDING(
+ neg_inf, LIBC_NAMESPACE::logf16(neg_zero), FE_DIVBYZERO);
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(zero,
+ LIBC_NAMESPACE::logf16(static_cast<float16>(1.0)));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(aNaN,
+ LIBC_NAMESPACE::logf16(static_cast<float16>(-1.0)));
+ EXPECT_MATH_ERRNO(EDOM);
+}
>From 2643dc91d4b0856ea3ddba0d2b3fa9b3720aebc1 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Mon, 26 Aug 2024 16:43:32 +0200
Subject: [PATCH 2/4] Fix nits and remove include that's no longer used
---
libc/src/math/generic/CMakeLists.txt | 1 -
libc/src/math/generic/expxf16.h | 30 +++++++++++++++-------------
libc/src/math/generic/logf16.cpp | 3 +--
libc/test/src/math/logf16_test.cpp | 2 +-
4 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index e7582c1939c760..10f1fb8aafdade 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -2299,7 +2299,6 @@ add_entrypoint_object(
.expxf16
libc.hdr.errno_macros
libc.hdr.fenv_macros
- libc.src.__support.CPP.array
libc.src.__support.FPUtil.except_value_utils
libc.src.__support.FPUtil.fenv_impl
libc.src.__support.FPUtil.fp_bits
diff --git a/libc/src/math/generic/expxf16.h b/libc/src/math/generic/expxf16.h
index cb73f6c180c600..a8ab4bbeca0fa1 100644
--- a/libc/src/math/generic/expxf16.h
+++ b/libc/src/math/generic/expxf16.h
@@ -292,26 +292,28 @@ template <bool IsSinh> LIBC_INLINE float16 eval_sinh_or_cosh(float16 x) {
// > display = hexadecimal;
// > for i from 0 to 31 do print(round(log(1 + i * 2^-5), SG, RN));
constexpr cpp::array<float, 32> LOGF_F = {
- 0x0p+0, 0x1.f829bp-6, 0x1.f0a30cp-5, 0x1.6f0d28p-4, 0x1.e27076p-4,
- 0x1.29553p-3, 0x1.5ff308p-3, 0x1.9525aap-3, 0x1.c8ff7cp-3, 0x1.fb9186p-3,
- 0x1.1675cap-2, 0x1.2e8e2cp-2, 0x1.4618bcp-2, 0x1.5d1bdcp-2, 0x1.739d8p-2,
- 0x1.89a338p-2, 0x1.9f323ep-2, 0x1.b44f78p-2, 0x1.c8ff7cp-2, 0x1.dd46ap-2,
- 0x1.f128f6p-2, 0x1.02552ap-1, 0x1.0be72ep-1, 0x1.154c3ep-1, 0x1.1e85f6p-1,
- 0x1.2795e2p-1, 0x1.307d74p-1, 0x1.393e0ep-1, 0x1.41d8fep-1, 0x1.4a4f86p-1,
- 0x1.52a2d2p-1, 0x1.5ad404p-1,
+ 0x0p+0f, 0x1.f829bp-6f, 0x1.f0a30cp-5f, 0x1.6f0d28p-4f,
+ 0x1.e27076p-4f, 0x1.29553p-3f, 0x1.5ff308p-3f, 0x1.9525aap-3f,
+ 0x1.c8ff7cp-3f, 0x1.fb9186p-3f, 0x1.1675cap-2f, 0x1.2e8e2cp-2f,
+ 0x1.4618bcp-2f, 0x1.5d1bdcp-2f, 0x1.739d8p-2f, 0x1.89a338p-2f,
+ 0x1.9f323ep-2f, 0x1.b44f78p-2f, 0x1.c8ff7cp-2f, 0x1.dd46ap-2f,
+ 0x1.f128f6p-2f, 0x1.02552ap-1f, 0x1.0be72ep-1f, 0x1.154c3ep-1f,
+ 0x1.1e85f6p-1f, 0x1.2795e2p-1f, 0x1.307d74p-1f, 0x1.393e0ep-1f,
+ 0x1.41d8fep-1f, 0x1.4a4f86p-1f, 0x1.52a2d2p-1f, 0x1.5ad404p-1f,
};
// Generated by Sollya with the following commands:
// > display = hexadecimal;
// > for i from 0 to 31 do print(round(1 / (1 + i * 2^-5), SG, RN));
constexpr cpp::array<float, 32> ONE_OVER_F = {
- 0x1p+0, 0x1.f07c2p-1, 0x1.e1e1e2p-1, 0x1.d41d42p-1, 0x1.c71c72p-1,
- 0x1.bacf92p-1, 0x1.af286cp-1, 0x1.a41a42p-1, 0x1.99999ap-1, 0x1.8f9c18p-1,
- 0x1.861862p-1, 0x1.7d05f4p-1, 0x1.745d18p-1, 0x1.6c16c2p-1, 0x1.642c86p-1,
- 0x1.5c9882p-1, 0x1.555556p-1, 0x1.4e5e0ap-1, 0x1.47ae14p-1, 0x1.414142p-1,
- 0x1.3b13b2p-1, 0x1.3521dp-1, 0x1.2f684cp-1, 0x1.29e412p-1, 0x1.24924ap-1,
- 0x1.1f7048p-1, 0x1.1a7b96p-1, 0x1.15b1e6p-1, 0x1.111112p-1, 0x1.0c9714p-1,
- 0x1.08421p-1, 0x1.041042p-1,
+ 0x1p+0f, 0x1.f07c2p-1f, 0x1.e1e1e2p-1f, 0x1.d41d42p-1f,
+ 0x1.c71c72p-1f, 0x1.bacf92p-1f, 0x1.af286cp-1f, 0x1.a41a42p-1f,
+ 0x1.99999ap-1f, 0x1.8f9c18p-1f, 0x1.861862p-1f, 0x1.7d05f4p-1f,
+ 0x1.745d18p-1f, 0x1.6c16c2p-1f, 0x1.642c86p-1f, 0x1.5c9882p-1f,
+ 0x1.555556p-1f, 0x1.4e5e0ap-1f, 0x1.47ae14p-1f, 0x1.414142p-1f,
+ 0x1.3b13b2p-1f, 0x1.3521dp-1f, 0x1.2f684cp-1f, 0x1.29e412p-1f,
+ 0x1.24924ap-1f, 0x1.1f7048p-1f, 0x1.1a7b96p-1f, 0x1.15b1e6p-1f,
+ 0x1.111112p-1f, 0x1.0c9714p-1f, 0x1.08421p-1f, 0x1.041042p-1f,
};
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/generic/logf16.cpp b/libc/src/math/generic/logf16.cpp
index adb24306a0f466..afc35b2b46e41a 100644
--- a/libc/src/math/generic/logf16.cpp
+++ b/libc/src/math/generic/logf16.cpp
@@ -10,7 +10,6 @@
#include "expxf16.h"
#include "hdr/errno_macros.h"
#include "hdr/fenv_macros.h"
-#include "src/__support/CPP/array.h"
#include "src/__support/FPUtil/FEnvImpl.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/PolyEval.h"
@@ -94,7 +93,7 @@ LLVM_LIBC_FUNCTION(float16, logf16, (float16 x)) {
return FPBits::zero().get_val();
// When x < 0.
- if (x_u > 0x8000) {
+ if (x_u > 0x8000U) {
fputil::set_errno_if_required(EDOM);
fputil::raise_except_if_required(FE_INVALID);
return FPBits::quiet_nan().get_val();
diff --git a/libc/test/src/math/logf16_test.cpp b/libc/test/src/math/logf16_test.cpp
index 67e5e172e53b8c..922918b092b21a 100644
--- a/libc/test/src/math/logf16_test.cpp
+++ b/libc/test/src/math/logf16_test.cpp
@@ -1,4 +1,4 @@
-//===-- Exhaustive test for logf16 ---------------------------------------===//
+//===-- Exhaustive test for logf16 ----------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
>From 16f4c7744ace0ce9c34b8f3349db278743e46170 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Mon, 26 Aug 2024 17:33:32 +0200
Subject: [PATCH 3/4] Remove duplicate comment
---
libc/src/math/generic/logf16.cpp | 1 -
1 file changed, 1 deletion(-)
diff --git a/libc/src/math/generic/logf16.cpp b/libc/src/math/generic/logf16.cpp
index afc35b2b46e41a..43be27cc68203f 100644
--- a/libc/src/math/generic/logf16.cpp
+++ b/libc/src/math/generic/logf16.cpp
@@ -36,7 +36,6 @@ static constexpr fputil::ExceptValues<float16, N_LOGF16_EXCEPTS>
{0x0987U, 0xc858U, 0U, 1U, 0U},
// x = 0x1.f2p-12, logf16(x) = -0x1.e98p+2 (RZ)
{0x0fc8U, 0xc7a6U, 0U, 1U, 1U},
-// x = 0x1.4d4p-9, logf16(x) = -0x1.7e4p+2 (RZ)
#endif
// x = 0x1.4d4p-9, logf16(x) = -0x1.7e4p+2 (RZ)
{0x1935U, 0xc5f9U, 0U, 1U, 0U},
>From 0541aa477433ea1ae5c2c081bfb50379fe6e1c6a Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Tue, 15 Oct 2024 16:52:25 +0200
Subject: [PATCH 4/4] Migrate to fputil::cast
---
libc/src/math/generic/CMakeLists.txt | 1 +
libc/src/math/generic/logf16.cpp | 11 ++++++-----
libc/test/src/math/smoke/CMakeLists.txt | 1 +
libc/test/src/math/smoke/logf16_test.cpp | 10 ++++++----
4 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 10f1fb8aafdade..b95672bc396878 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -2299,6 +2299,7 @@ add_entrypoint_object(
.expxf16
libc.hdr.errno_macros
libc.hdr.fenv_macros
+ libc.src.__support.FPUtil.cast
libc.src.__support.FPUtil.except_value_utils
libc.src.__support.FPUtil.fenv_impl
libc.src.__support.FPUtil.fp_bits
diff --git a/libc/src/math/generic/logf16.cpp b/libc/src/math/generic/logf16.cpp
index 43be27cc68203f..9d1af2baa26153 100644
--- a/libc/src/math/generic/logf16.cpp
+++ b/libc/src/math/generic/logf16.cpp
@@ -13,6 +13,7 @@
#include "src/__support/FPUtil/FEnvImpl.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/PolyEval.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/common.h"
@@ -119,11 +120,11 @@ LLVM_LIBC_FUNCTION(float16, logf16, (float16 x)) {
int m = -FPBits::EXP_BIAS;
- // When x is subnormal.
+ // When x is subnormal, normalize it.
if ((x_u & FPBits::EXP_MASK) == 0U) {
- // Normalize x.
- x_bits = FPBits(x_bits.get_val() *
- static_cast<float16>((1U << FPBits::FRACTION_LEN)));
+ // Can't pass an integer to fputil::cast directly.
+ constexpr float NORMALIZE_EXP = 1U << FPBits::FRACTION_LEN;
+ x_bits = FPBits(x_bits.get_val() * fputil::cast<float16>(NORMALIZE_EXP));
x_u = x_bits.uintval();
m -= FPBits::FRACTION_LEN;
}
@@ -149,7 +150,7 @@ LLVM_LIBC_FUNCTION(float16, logf16, (float16 x)) {
v * fputil::polyeval(v, 0x1p+0f, -0x1.001804p-1f, 0x1.557ef6p-2f);
// log(1.mant) = log(f) + log(1 + d/f)
float log_1_mant = LOGF_F[f] + log1p_d_over_f;
- return static_cast<float16>(
+ return fputil::cast<float16>(
fputil::multiply_add(static_cast<float>(m), LOGF_2, log_1_mant));
}
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index a1ccd261f97abb..a3cd671269caa1 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3568,6 +3568,7 @@ add_fp_unittest(
libc.hdr.fenv_macros
libc.src.errno.errno
libc.src.math.logf16
+ libc.src.__support.FPUtil.cast
)
add_fp_unittest(
diff --git a/libc/test/src/math/smoke/logf16_test.cpp b/libc/test/src/math/smoke/logf16_test.cpp
index e2f21003e8d81b..c7232aa1c1e323 100644
--- a/libc/test/src/math/smoke/logf16_test.cpp
+++ b/libc/test/src/math/smoke/logf16_test.cpp
@@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//
#include "hdr/fenv_macros.h"
+#include "src/__support/FPUtil/cast.h"
#include "src/errno/libc_errno.h"
#include "src/math/logf16.h"
#include "test/UnitTest/FPMatcher.h"
@@ -37,11 +38,12 @@ TEST_F(LlvmLibcLogf16Test, SpecialNumbers) {
neg_inf, LIBC_NAMESPACE::logf16(neg_zero), FE_DIVBYZERO);
EXPECT_MATH_ERRNO(0);
- EXPECT_FP_EQ_ALL_ROUNDING(zero,
- LIBC_NAMESPACE::logf16(static_cast<float16>(1.0)));
+ EXPECT_FP_EQ_ALL_ROUNDING(
+ zero, LIBC_NAMESPACE::logf16(LIBC_NAMESPACE::fputil::cast<float16>(1.0)));
EXPECT_MATH_ERRNO(0);
- EXPECT_FP_EQ_ALL_ROUNDING(aNaN,
- LIBC_NAMESPACE::logf16(static_cast<float16>(-1.0)));
+ EXPECT_FP_EQ_ALL_ROUNDING(
+ aNaN,
+ LIBC_NAMESPACE::logf16(LIBC_NAMESPACE::fputil::cast<float16>(-1.0)));
EXPECT_MATH_ERRNO(EDOM);
}
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