[libc-commits] [libc] [libc][math][c23] Add exp2m1f16 C23 math function (PR #105690)
via libc-commits
libc-commits at lists.llvm.org
Thu Aug 22 09:36:02 PDT 2024
https://github.com/overmighty updated https://github.com/llvm/llvm-project/pull/105690
>From 22d56a5513bdaa6e4eaa249757e77d97a2ea585c Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Thu, 22 Aug 2024 18:18:34 +0200
Subject: [PATCH 1/2] [libc][math][c23] Add exp2m1f16 C23 math function
Part of #95250.
---
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/exp2m1f16.h | 21 +++
libc/src/math/generic/CMakeLists.txt | 26 +++-
libc/src/math/generic/exp2f16.cpp | 39 +----
libc/src/math/generic/exp2m1f16.cpp | 161 ++++++++++++++++++++
libc/src/math/generic/expxf16.h | 38 +++++
libc/test/src/math/CMakeLists.txt | 11 ++
libc/test/src/math/exp2m1f16_test.cpp | 40 +++++
libc/test/src/math/smoke/CMakeLists.txt | 11 ++
libc/test/src/math/smoke/exp2m1f16_test.cpp | 94 ++++++++++++
13 files changed, 404 insertions(+), 42 deletions(-)
create mode 100644 libc/src/math/exp2m1f16.h
create mode 100644 libc/src/math/generic/exp2m1f16.cpp
create mode 100644 libc/test/src/math/exp2m1f16_test.cpp
create mode 100644 libc/test/src/math/smoke/exp2m1f16_test.cpp
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 65c5757efe6274..06ca526c671ea8 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -596,6 +596,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
libc.src.math.copysignf16
libc.src.math.exp10f16
libc.src.math.exp2f16
+ libc.src.math.exp2m1f16
libc.src.math.expf16
libc.src.math.expm1f16
libc.src.math.f16add
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 185d2d440849a0..0d2bbdd3381d19 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -292,7 +292,7 @@ Higher Math Functions
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
| exp2 | |check| | |check| | | |check| | | 7.12.6.4 | F.10.3.4 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| exp2m1 | |check| | | | | | 7.12.6.5 | F.10.3.5 |
+| exp2m1 | |check| | | | |check| | | 7.12.6.5 | F.10.3.5 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
| expm1 | |check| | |check| | | |check| | | 7.12.6.6 | F.10.3.6 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 118dcce829be23..c75343d567d7f9 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -596,6 +596,7 @@ def StdC : StandardSpec<"stdc"> {
GuardedFunctionSpec<"exp2f16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
FunctionSpec<"exp2m1f", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+ GuardedFunctionSpec<"exp2m1f16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
FunctionSpec<"expm1", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
FunctionSpec<"expm1f", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 3cba34fc249322..bd18c68a5e2fd6 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -115,6 +115,7 @@ add_math_entrypoint_object(exp2f)
add_math_entrypoint_object(exp2f16)
add_math_entrypoint_object(exp2m1f)
+add_math_entrypoint_object(exp2m1f16)
add_math_entrypoint_object(exp10)
add_math_entrypoint_object(exp10f)
diff --git a/libc/src/math/exp2m1f16.h b/libc/src/math/exp2m1f16.h
new file mode 100644
index 00000000000000..39fcebd5a69300
--- /dev/null
+++ b/libc/src/math/exp2m1f16.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for exp2m1f16 ---------------------*- 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_EXP2M1F16_H
+#define LLVM_LIBC_SRC_MATH_EXP2M1F16_H
+
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+float16 exp2m1f16(float16 x);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_MATH_EXP2M1F16_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 350072f4b9649d..c565dd5cb04f5a 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -1441,13 +1441,9 @@ 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
- libc.src.__support.FPUtil.multiply_add
- libc.src.__support.FPUtil.nearest_integer
- libc.src.__support.FPUtil.polyeval
libc.src.__support.FPUtil.rounding_mode
libc.src.__support.macros.optimization
COMPILE_OPTIONS
@@ -1475,6 +1471,28 @@ add_entrypoint_object(
-O3
)
+add_entrypoint_object(
+ exp2m1f16
+ SRCS
+ exp2m1f16.cpp
+ HDRS
+ ../exp2m1f16.h
+ DEPENDS
+ .expxf16
+ libc.hdr.errno_macros
+ libc.hdr.fenv_macros
+ libc.src.__support.common
+ 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.FPUtil.rounding_mode
+ libc.src.__support.macros.optimization
+ COMPILE_OPTIONS
+ -O3
+)
+
add_entrypoint_object(
exp10
SRCS
diff --git a/libc/src/math/generic/exp2f16.cpp b/libc/src/math/generic/exp2f16.cpp
index 66b79567040053..09d61d04d4cda9 100644
--- a/libc/src/math/generic/exp2f16.cpp
+++ b/libc/src/math/generic/exp2f16.cpp
@@ -10,13 +10,9 @@
#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/FPUtil/nearest_integer.h"
#include "src/__support/FPUtil/rounding_mode.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
@@ -88,39 +84,8 @@ LLVM_LIBC_FUNCTION(float16, exp2f16, (float16 x)) {
if (auto r = EXP2F16_EXCEPTS.lookup(x_u); LIBC_UNLIKELY(r.has_value()))
return r.value();
- // For -25 < x < 16, to compute 2^x, we perform the following range reduction:
- // find hi, mid, lo, such that:
- // x = hi + mid + lo, in which
- // hi is an integer,
- // mid * 2^3 is an integer,
- // -2^(-4) <= lo < 2^(-4).
- // In particular,
- // hi + mid = round(x * 2^3) * 2^(-3).
- // Then,
- // 2^x = 2^(hi + mid + lo) = 2^hi * 2^mid * 2^lo.
- // We store 2^mid in the lookup table EXP2_MID_BITS, and compute 2^hi * 2^mid
- // by adding hi to the exponent field of 2^mid. 2^lo is computed using a
- // degree-3 minimax polynomial generated by Sollya.
-
- float xf = x;
- float kf = fputil::nearest_integer(xf * 0x1.0p+3f);
- int x_hi_mid = static_cast<int>(kf);
- int x_hi = x_hi_mid >> 3;
- int x_mid = x_hi_mid & 0x7;
- // lo = x - (hi + mid) = round(x * 2^3) * (-2^(-3)) + x
- float lo = fputil::multiply_add(kf, -0x1.0p-3f, xf);
-
- uint32_t exp2_hi_mid_bits =
- EXP2_MID_BITS[x_mid] +
- static_cast<uint32_t>(x_hi << fputil::FPBits<float>::FRACTION_LEN);
- float exp2_hi_mid = fputil::FPBits<float>(exp2_hi_mid_bits).get_val();
- // Degree-3 minimax polynomial generated by Sollya with the following
- // commands:
- // > display = hexadecimal;
- // > P = fpminimax((2^x - 1)/x, 2, [|SG...|], [-2^-4, 2^-4]);
- // > 1 + x * P;
- float exp2_lo = fputil::polyeval(lo, 0x1p+0f, 0x1.62e43p-1f, 0x1.ec0aa6p-3f,
- 0x1.c6b4a6p-5f);
+ // exp2(x) = exp2(hi + mid) * exp2(lo)
+ auto [exp2_hi_mid, exp2_lo] = exp2_range_reduction(x);
return static_cast<float16>(exp2_hi_mid * exp2_lo);
}
diff --git a/libc/src/math/generic/exp2m1f16.cpp b/libc/src/math/generic/exp2m1f16.cpp
new file mode 100644
index 00000000000000..9d01e80ea59e2a
--- /dev/null
+++ b/libc/src/math/generic/exp2m1f16.cpp
@@ -0,0 +1,161 @@
+//===-- Half-precision 2^x - 1 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/exp2m1f16.h"
+#include "expxf16.h"
+#include "hdr/errno_macros.h"
+#include "hdr/fenv_macros.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/FPUtil/rounding_mode.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/optimization.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+static constexpr fputil::ExceptValues<float16, 6> EXP2M1F16_EXCEPTS_LO = {{
+ // (input, RZ output, RU offset, RD offset, RN offset)
+ // x = 0x1.cf4p-13, exp2m1f16(x) = 0x1.41p-13 (RZ)
+ {0x0b3dU, 0x0904U, 1U, 0U, 1U},
+ // x = 0x1.4fcp-12, exp2m1f16(x) = 0x1.d14p-13 (RZ)
+ {0x0d3fU, 0x0b45U, 1U, 0U, 1U},
+ // x = 0x1.63p-11, exp2m1f16(x) = 0x1.ec4p-12 (RZ)
+ {0x118cU, 0x0fb1U, 1U, 0U, 0U},
+ // x = 0x1.6fp-7, exp2m1f16(x) = 0x1.fe8p-8 (RZ)
+ {0x21bcU, 0x1ffaU, 1U, 0U, 1U},
+ // x = -0x1.c6p-10, exp2m1f16(x) = -0x1.3a8p-10 (RZ)
+ {0x9718U, 0x94eaU, 0U, 1U, 0U},
+ // x = -0x1.cfcp-10, exp2m1f16(x) = -0x1.414p-10 (RZ)
+ {0x973fU, 0x9505U, 0U, 1U, 0U},
+}};
+
+#ifdef LIBC_TARGET_CPU_HAS_FMA
+static constexpr size_t N_EXP2M1F16_EXCEPTS_HI = 6;
+#else
+static constexpr size_t N_EXP2M1F16_EXCEPTS_HI = 7;
+#endif
+
+static constexpr fputil::ExceptValues<float16, N_EXP2M1F16_EXCEPTS_HI>
+ EXP2M1F16_EXCEPTS_HI = {{
+ // (input, RZ output, RU offset, RD offset, RN offset)
+ // x = 0x1.e58p-3, exp2m1f16(x) = 0x1.6dcp-3 (RZ)
+ {0x3396U, 0x31b7U, 1U, 0U, 0U},
+#ifndef LIBC_TARGET_CPU_HAS_FMA
+ // x = 0x1.2e8p-2, exp2m1f16(x) = 0x1.d14p-3 (RZ)
+ {0x34baU, 0x3345U, 1U, 0U, 0U},
+#endif
+ // x = 0x1.ad8p-2, exp2m1f16(x) = 0x1.598p-2 (RZ)
+ {0x36b6U, 0x3566U, 1U, 0U, 0U},
+#ifdef LIBC_TARGET_CPU_HAS_FMA
+ // x = 0x1.edcp-2, exp2m1f16(x) = 0x1.964p-2 (RZ)
+ {0x37b7U, 0x3659U, 1U, 0U, 1U},
+#endif
+ // x = -0x1.804p-3, exp2m1f16(x) = -0x1.f34p-4 (RZ)
+ {0xb201U, 0xafcdU, 0U, 1U, 1U},
+ // x = -0x1.f3p-3, exp2m1f16(x) = -0x1.3e4p-3 (RZ)
+ {0xb3ccU, 0xb0f9U, 0U, 1U, 0U},
+ // x = -0x1.294p-1, exp2m1f16(x) = -0x1.53p-2 (RZ)
+ {0xb8a5U, 0xb54cU, 0U, 1U, 1U},
+#ifndef LIBC_TARGET_CPU_HAS_FMA
+ // x = -0x1.a34p-1, exp2m1f16(x) = -0x1.bb4p-2 (RZ)
+ {0xba8dU, 0xb6edU, 0U, 1U, 1U},
+#endif
+ }};
+
+LLVM_LIBC_FUNCTION(float16, exp2m1f16, (float16 x)) {
+ using FPBits = fputil::FPBits<float16>;
+ FPBits x_bits(x);
+
+ uint16_t x_u = x_bits.uintval();
+ uint16_t x_abs = x_u & 0x7fffU;
+
+ // When |x| <= 2^(-3), or |x| >= 11, or x is NaN.
+ if (LIBC_UNLIKELY(x_abs <= 0x3000U || x_abs >= 0x4980U)) {
+ // exp2m1(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;
+ }
+
+ // When x >= 16.
+ if (x_u >= 0x4c00 && x_bits.is_pos()) {
+ // exp2m1(+inf) = +inf
+ if (x_bits.is_inf())
+ return FPBits::inf().get_val();
+
+ switch (fputil::quick_get_round()) {
+ case FE_TONEAREST:
+ case FE_UPWARD:
+ fputil::set_errno_if_required(ERANGE);
+ fputil::raise_except_if_required(FE_OVERFLOW | FE_INEXACT);
+ return FPBits::inf().get_val();
+ default:
+ return FPBits::max_normal().get_val();
+ }
+ }
+
+ // When x < -11.
+ if (x_u > 0xc980U) {
+ // exp2m1(-inf) = -1
+ if (x_bits.is_inf())
+ return FPBits::one(Sign::NEG).get_val();
+
+ // When -12 < x < -11, round(2^x - 1, HP, RN) = -0x1.ffcp-1.
+ if (x_u < 0xca00U) {
+ return fputil::round_result_slightly_down(
+ static_cast<float16>(-0x1.ffcp-1));
+ }
+
+ // When x <= -12, round(2^x - 1, HP, RN) = -1.
+ switch (fputil::quick_get_round()) {
+ case FE_TONEAREST:
+ case FE_DOWNWARD:
+ return FPBits::one(Sign::NEG).get_val();
+ default:
+ return static_cast<float16>(-0x1.ffcp-1);
+ }
+ }
+
+ // When |x| <= 2^(-3).
+ if (x_abs <= 0x3000U) {
+ if (auto r = EXP2M1F16_EXCEPTS_LO.lookup(x_u);
+ LIBC_UNLIKELY(r.has_value()))
+ return r.value();
+
+ float xf = x;
+ // Degree-5 minimax polynomial generated by Sollya with the following
+ // commands:
+ // > display = hexadecimal;
+ // > P = fpminimax((2^x - 1)/x, 4, [|SG...|], [-2^-3, 2^-3]);
+ // > x * P;
+ return static_cast<float16>(
+ xf * fputil::polyeval(xf, 0x1.62e43p-1f, 0x1.ebfbdep-3f,
+ 0x1.c6af88p-5f, 0x1.3b45d6p-7f,
+ 0x1.641e7cp-10f));
+ }
+ }
+
+ if (auto r = EXP2M1F16_EXCEPTS_HI.lookup(x_u); LIBC_UNLIKELY(r.has_value()))
+ return r.value();
+
+ // exp2(x) = exp2(hi + mid) * exp2(lo)
+ auto [exp2_hi_mid, exp2_lo] = exp2_range_reduction(x);
+ // exp2m1(x) = exp2(hi + mid) * exp2(lo) - 1
+ return static_cast<float16>(
+ fputil::multiply_add(exp2_hi_mid, exp2_lo, -1.0f));
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/generic/expxf16.h b/libc/src/math/generic/expxf16.h
index a0db6cee438e92..35294130a15007 100644
--- a/libc/src/math/generic/expxf16.h
+++ b/libc/src/math/generic/expxf16.h
@@ -10,6 +10,7 @@
#define LLVM_LIBC_SRC_MATH_GENERIC_EXPXF16_H
#include "src/__support/CPP/array.h"
+#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/PolyEval.h"
#include "src/__support/FPUtil/multiply_add.h"
#include "src/__support/FPUtil/nearest_integer.h"
@@ -89,6 +90,43 @@ constexpr cpp::array<uint32_t, 8> EXP2_MID_BITS = {
0x3fb5'04f3U, 0x3fc5'672aU, 0x3fd7'44fdU, 0x3fea'c0c7U,
};
+LIBC_INLINE ExpRangeReduction exp2_range_reduction(float16 x) {
+ // For -25 < x < 16, to compute 2^x, we perform the following range reduction:
+ // find hi, mid, lo, such that:
+ // x = hi + mid + lo, in which
+ // hi is an integer,
+ // mid * 2^3 is an integer,
+ // -2^(-4) <= lo < 2^(-4).
+ // In particular,
+ // hi + mid = round(x * 2^3) * 2^(-3).
+ // Then,
+ // 2^x = 2^(hi + mid + lo) = 2^hi * 2^mid * 2^lo.
+ // We store 2^mid in the lookup table EXP2_MID_BITS, and compute 2^hi * 2^mid
+ // by adding hi to the exponent field of 2^mid. 2^lo is computed using a
+ // degree-3 minimax polynomial generated by Sollya.
+
+ float xf = x;
+ float kf = fputil::nearest_integer(xf * 0x1.0p+3f);
+ int x_hi_mid = static_cast<int>(kf);
+ int x_hi = x_hi_mid >> 3;
+ int x_mid = x_hi_mid & 0x7;
+ // lo = x - (hi + mid) = round(x * 2^3) * (-2^(-3)) + x
+ float lo = fputil::multiply_add(kf, -0x1.0p-3f, xf);
+
+ uint32_t exp2_hi_mid_bits =
+ EXP2_MID_BITS[x_mid] +
+ static_cast<uint32_t>(x_hi << fputil::FPBits<float>::FRACTION_LEN);
+ float exp2_hi_mid = fputil::FPBits<float>(exp2_hi_mid_bits).get_val();
+ // Degree-3 minimax polynomial generated by Sollya with the following
+ // commands:
+ // > display = hexadecimal;
+ // > P = fpminimax((2^x - 1)/x, 2, [|SG...|], [-2^-4, 2^-4]);
+ // > 1 + x * P;
+ float exp2_lo = fputil::polyeval(lo, 0x1p+0f, 0x1.62e43p-1f, 0x1.ec0aa6p-3f,
+ 0x1.c6b4a6p-5f);
+ return {exp2_hi_mid, exp2_lo};
+}
+
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC_MATH_GENERIC_EXPXF16_H
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 0c4118c3694548..07a9405081f97d 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1003,6 +1003,17 @@ add_fp_unittest(
libc.src.__support.FPUtil.fp_bits
)
+add_fp_unittest(
+ exp2m1f16_test
+ NEED_MPFR
+ SUITE
+ libc-math-unittests
+ SRCS
+ exp2m1f16_test.cpp
+ DEPENDS
+ libc.src.math.exp2m1f16
+)
+
add_fp_unittest(
exp10_test
NEED_MPFR
diff --git a/libc/test/src/math/exp2m1f16_test.cpp b/libc/test/src/math/exp2m1f16_test.cpp
new file mode 100644
index 00000000000000..bf299118429d7e
--- /dev/null
+++ b/libc/test/src/math/exp2m1f16_test.cpp
@@ -0,0 +1,40 @@
+//===-- Exhaustive test for exp2m1f16 -------------------------------------===//
+//
+// 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/exp2m1f16.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+using LlvmLibcExp2m1f16Test = 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(LlvmLibcExp2m1f16Test, PositiveRange) {
+ for (uint16_t v = POS_START; v <= POS_STOP; ++v) {
+ float16 x = FPBits(v).get_val();
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2m1, x,
+ LIBC_NAMESPACE::exp2m1f16(x), 0.5);
+ }
+}
+
+TEST_F(LlvmLibcExp2m1f16Test, NegativeRange) {
+ for (uint16_t v = NEG_START; v <= NEG_STOP; ++v) {
+ float16 x = FPBits(v).get_val();
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2m1, x,
+ LIBC_NAMESPACE::exp2m1f16(x), 0.5);
+ }
+}
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 7271e933b9311d..349716d44cfb20 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -1106,6 +1106,17 @@ add_fp_unittest(
libc.src.math.exp2m1f
)
+add_fp_unittest(
+ exp2m1f16_test
+ SUITE
+ libc-math-smoke-tests
+ SRCS
+ exp2m1f16_test.cpp
+ DEPENDS
+ libc.src.errno.errno
+ libc.src.math.exp2m1f16
+)
+
add_fp_unittest(
exp10_test
SUITE
diff --git a/libc/test/src/math/smoke/exp2m1f16_test.cpp b/libc/test/src/math/smoke/exp2m1f16_test.cpp
new file mode 100644
index 00000000000000..7e6c2050abbbad
--- /dev/null
+++ b/libc/test/src/math/smoke/exp2m1f16_test.cpp
@@ -0,0 +1,94 @@
+//===-- Unittests for exp2m1f16 -------------------------------------------===//
+//
+// 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/errno_macros.h"
+#include "hdr/fenv_macros.h"
+#include "src/errno/libc_errno.h"
+#include "src/math/exp2m1f16.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using LlvmLibcExp2m1f16Test = LIBC_NAMESPACE::testing::FPTest<float16>;
+
+TEST_F(LlvmLibcExp2m1f16Test, SpecialNumbers) {
+ LIBC_NAMESPACE::libc_errno = 0;
+
+ EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::exp2m1f16(aNaN));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION(aNaN, LIBC_NAMESPACE::exp2m1f16(sNaN),
+ FE_INVALID);
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(inf, LIBC_NAMESPACE::exp2m1f16(inf));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(static_cast<float16>(-1.0),
+ LIBC_NAMESPACE::exp2m1f16(neg_inf));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::exp2m1f16(zero));
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::exp2m1f16(neg_zero));
+ EXPECT_MATH_ERRNO(0);
+}
+
+TEST_F(LlvmLibcExp2m1f16Test, Overflow) {
+ LIBC_NAMESPACE::libc_errno = 0;
+
+ EXPECT_FP_EQ_WITH_EXCEPTION(inf, LIBC_NAMESPACE::exp2m1f16(max_normal),
+ FE_OVERFLOW | FE_INEXACT);
+ EXPECT_MATH_ERRNO(ERANGE);
+
+ float16 x = static_cast<float16>(16.0);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_NEAREST(
+ inf, LIBC_NAMESPACE::exp2m1f16(x), FE_OVERFLOW | FE_INEXACT);
+ EXPECT_MATH_ERRNO(ERANGE);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_UPWARD(inf, LIBC_NAMESPACE::exp2m1f16(x),
+ FE_OVERFLOW | FE_INEXACT);
+ EXPECT_MATH_ERRNO(ERANGE);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_DOWNWARD(
+ max_normal, LIBC_NAMESPACE::exp2m1f16(x), FE_INEXACT);
+ EXPECT_MATH_ERRNO(0);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_TOWARD_ZERO(
+ max_normal, LIBC_NAMESPACE::exp2m1f16(x), FE_INEXACT);
+ EXPECT_MATH_ERRNO(0);
+}
+
+TEST_F(LlvmLibcExp2m1f16Test, ResultNearNegOne) {
+ LIBC_NAMESPACE::libc_errno = 0;
+
+ EXPECT_FP_EQ_WITH_EXCEPTION(static_cast<float16>(-1.0),
+ LIBC_NAMESPACE::exp2m1f16(neg_max_normal),
+ FE_INEXACT);
+
+ EXPECT_FP_EQ_ALL_ROUNDING(
+ static_cast<float16>(-0x1.ffcp-1),
+ LIBC_NAMESPACE::exp2m1f16(static_cast<float16>(-11)));
+
+ float16 x = static_cast<float16>(-12);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_NEAREST(
+ static_cast<float16>(-1.0), LIBC_NAMESPACE::exp2m1f16(x), FE_INEXACT);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_UPWARD(static_cast<float16>(-0x1.ffcp-1),
+ LIBC_NAMESPACE::exp2m1f16(x),
+ FE_INEXACT);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_DOWNWARD(
+ static_cast<float16>(-1.0), LIBC_NAMESPACE::exp2m1f16(x), FE_INEXACT);
+
+ EXPECT_FP_EQ_WITH_EXCEPTION_ROUNDING_TOWARD_ZERO(
+ static_cast<float16>(-0x1.ffcp-1), LIBC_NAMESPACE::exp2m1f16(x),
+ FE_INEXACT);
+}
>From 8f156b3ebef84771cd6a0057f36796448782058f Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Thu, 22 Aug 2024 18:35:15 +0200
Subject: [PATCH 2/2] Enable exp2m1f16 entrypoint on GPUs
---
libc/config/gpu/entrypoints.txt | 1 +
1 file changed, 1 insertion(+)
diff --git a/libc/config/gpu/entrypoints.txt b/libc/config/gpu/entrypoints.txt
index d7f35bc1edf5a0..7c9a509647363e 100644
--- a/libc/config/gpu/entrypoints.txt
+++ b/libc/config/gpu/entrypoints.txt
@@ -486,6 +486,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
libc.src.math.ceilf16
libc.src.math.copysignf16
libc.src.math.exp10f16
+ libc.src.math.exp10m1f16
libc.src.math.exp2f16
libc.src.math.expf16
libc.src.math.f16add
More information about the libc-commits
mailing list