[libc-commits] [libc] [libc][math][c23] Add f16{add, sub}{, l, f128} C23 math functions (PR #97072)

via libc-commits libc-commits at lists.llvm.org
Sat Jun 29 16:45:50 PDT 2024


https://github.com/overmighty updated https://github.com/llvm/llvm-project/pull/97072

>From 096f017dbf93e79c9f4d8489ecd54d04984a6edd Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Sat, 22 Jun 2024 03:19:59 +0200
Subject: [PATCH 01/12] [libc][math][c23] Add f16addf C23 math function

---
 libc/config/linux/aarch64/entrypoints.txt     |   1 +
 libc/config/linux/x86_64/entrypoints.txt      |   1 +
 libc/docs/math/index.rst                      |   2 +
 libc/spec/stdc.td                             |   2 +
 .../__support/FPUtil/generic/CMakeLists.txt   |  19 ++
 libc/src/__support/FPUtil/generic/add.h       | 171 ++++++++++++++++++
 libc/src/math/CMakeLists.txt                  |   2 +
 libc/src/math/f16addf.h                       |  20 ++
 libc/src/math/generic/CMakeLists.txt          |  13 ++
 libc/src/math/generic/f16addf.cpp             |  19 ++
 libc/test/src/math/AddTest.h                  |  74 ++++++++
 libc/test/src/math/CMakeLists.txt             |  13 ++
 libc/test/src/math/f16addf_test.cpp           |  13 ++
 libc/test/src/math/smoke/AddTest.h            | 156 ++++++++++++++++
 libc/test/src/math/smoke/CMakeLists.txt       |  15 ++
 libc/test/src/math/smoke/f16addf_test.cpp     |  13 ++
 libc/utils/MPFRWrapper/MPFRUtils.cpp          |   8 +
 libc/utils/MPFRWrapper/MPFRUtils.h            |   5 +-
 18 files changed, 546 insertions(+), 1 deletion(-)
 create mode 100644 libc/src/__support/FPUtil/generic/add.h
 create mode 100644 libc/src/math/f16addf.h
 create mode 100644 libc/src/math/generic/f16addf.cpp
 create mode 100644 libc/test/src/math/AddTest.h
 create mode 100644 libc/test/src/math/f16addf_test.cpp
 create mode 100644 libc/test/src/math/smoke/AddTest.h
 create mode 100644 libc/test/src/math/smoke/f16addf_test.cpp

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 8a26536cea9a0..aef77bbdf71b1 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -507,6 +507,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.canonicalizef16
     libc.src.math.ceilf16
     libc.src.math.copysignf16
+    libc.src.math.f16addf
     libc.src.math.f16div
     libc.src.math.f16divf
     libc.src.math.f16fmaf
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index e1922ca94b97e..a806d22cc4417 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -537,6 +537,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.canonicalizef16
     libc.src.math.ceilf16
     libc.src.math.copysignf16
+    libc.src.math.f16addf
     libc.src.math.f16div
     libc.src.math.f16divf
     libc.src.math.f16divl
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 1bc75a9e0517f..984addfc6a7a5 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -124,6 +124,8 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | dsub             | N/A              | N/A             |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
+| f16add           | |check|          |                 |                        | N/A                  |                        | 7.12.14.1              | F.10.11                    |
++------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16div           | |check|\*        | |check|\*       | |check|\*              | N/A                  | |check|                | 7.12.14.4              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16fma           | |check|          | |check|         | |check|                | N/A                  | |check|                | 7.12.14.5              | F.10.11                    |
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 481515ad439ed..b9ddc22ed445d 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -729,6 +729,8 @@ def StdC : StandardSpec<"stdc"> {
 
           GuardedFunctionSpec<"setpayloadsigf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
+          GuardedFunctionSpec<"f16addf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
+
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16sqrtf", RetValSpec<Float16Type>, [ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
diff --git a/libc/src/__support/FPUtil/generic/CMakeLists.txt b/libc/src/__support/FPUtil/generic/CMakeLists.txt
index bd8af98473edf..288169ea760bf 100644
--- a/libc/src/__support/FPUtil/generic/CMakeLists.txt
+++ b/libc/src/__support/FPUtil/generic/CMakeLists.txt
@@ -48,6 +48,25 @@ add_header_library(
     libc.src.__support.macros.optimization
 )
 
+add_header_library(
+  add
+  HDRS
+    add.h
+  DEPENDS
+    libc.hdr.errno_macros
+    libc.hdr.fenv_macros
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.CPP.bit
+    libc.src.__support.CPP.type_traits
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.FPUtil.fenv_impl
+    libc.src.__support.FPUtil.fp_bits
+    libc.src.__support.FPUtil.dyadic_float
+    libc.src.__support.FPUtil.rounding_mode
+    libc.src.__support.macros.attributes
+    libc.src.__support.macros.optimization
+)
+
 add_header_library(
   div
   HDRS
diff --git a/libc/src/__support/FPUtil/generic/add.h b/libc/src/__support/FPUtil/generic/add.h
new file mode 100644
index 0000000000000..a987c38236396
--- /dev/null
+++ b/libc/src/__support/FPUtil/generic/add.h
@@ -0,0 +1,171 @@
+//===-- Addition of IEEE 754 floating-point numbers -------------*- 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___SUPPORT_FPUTIL_GENERIC_ADD_H
+#define LLVM_LIBC_SRC___SUPPORT_FPUTIL_GENERIC_ADD_H
+
+#include "hdr/errno_macros.h"
+#include "hdr/fenv_macros.h"
+#include "src/__support/CPP/algorithm.h"
+#include "src/__support/CPP/bit.h"
+#include "src/__support/CPP/type_traits.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/dyadic_float.h"
+#include "src/__support/FPUtil/rounding_mode.h"
+#include "src/__support/macros/attributes.h"
+#include "src/__support/macros/optimization.h"
+
+namespace LIBC_NAMESPACE::fputil::generic {
+
+template <typename OutType, typename InType>
+LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<OutType> &&
+                                 cpp::is_floating_point_v<InType> &&
+                                 sizeof(OutType) <= sizeof(InType),
+                             OutType>
+add(InType x, InType y) {
+  using OutFPBits = FPBits<OutType>;
+  using OutStorageType = typename OutFPBits::StorageType;
+  using InFPBits = FPBits<InType>;
+  using InStorageType = typename InFPBits::StorageType;
+
+  constexpr int GUARD_BITS_LEN = 3;
+  constexpr int RESULT_FRACTION_LEN = InFPBits::FRACTION_LEN + GUARD_BITS_LEN;
+  constexpr int RESULT_MANTISSA_LEN = RESULT_FRACTION_LEN + 1;
+
+  using DyadicFloat =
+      DyadicFloat<cpp::bit_ceil(static_cast<size_t>(RESULT_MANTISSA_LEN))>;
+
+  InFPBits x_bits(x);
+  InFPBits y_bits(y);
+
+  if (LIBC_UNLIKELY(x_bits.is_inf_or_nan() || y_bits.is_inf_or_nan() ||
+                    x_bits.is_zero() || y_bits.is_zero())) {
+    if (x_bits.is_nan() || y_bits.is_nan()) {
+      if (x_bits.is_signaling_nan() || y_bits.is_signaling_nan())
+        raise_except_if_required(FE_INVALID);
+
+      if (x_bits.is_quiet_nan()) {
+        InStorageType x_payload = static_cast<InStorageType>(getpayload(x));
+        if ((x_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
+          return OutFPBits::quiet_nan(x_bits.sign(),
+                                      static_cast<OutStorageType>(x_payload))
+              .get_val();
+      }
+
+      if (y_bits.is_quiet_nan()) {
+        InStorageType y_payload = static_cast<InStorageType>(getpayload(y));
+        if ((y_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
+          return OutFPBits::quiet_nan(y_bits.sign(),
+                                      static_cast<OutStorageType>(y_payload))
+              .get_val();
+      }
+
+      return OutFPBits::quiet_nan().get_val();
+    }
+
+    if (x_bits.is_inf()) {
+      if (y_bits.is_inf()) {
+        if (x_bits.sign() != y_bits.sign()) {
+          raise_except_if_required(FE_INVALID);
+          return OutFPBits::quiet_nan().get_val();
+        }
+
+        return OutFPBits::inf(x_bits.sign()).get_val();
+      }
+
+      return OutFPBits::inf(x_bits.sign()).get_val();
+    }
+
+    if (y_bits.is_inf())
+      return OutFPBits::inf(y_bits.sign()).get_val();
+
+    if (x_bits.is_zero()) {
+      if (y_bits.is_zero()) {
+        switch (quick_get_round()) {
+        case FE_DOWNWARD:
+          return OutFPBits::zero(Sign::NEG).get_val();
+        default:
+          return OutFPBits::zero(Sign::POS).get_val();
+        }
+      }
+
+      return static_cast<OutType>(y);
+    }
+
+    if (y_bits.is_zero())
+      return static_cast<OutType>(x);
+  }
+
+  InType x_abs = x_bits.abs().get_val();
+  InType y_abs = y_bits.abs().get_val();
+
+  if (x_abs == y_abs && x_bits.sign() != y_bits.sign()) {
+    switch (quick_get_round()) {
+    case FE_DOWNWARD:
+      return OutFPBits::zero(Sign::NEG).get_val();
+    default:
+      return OutFPBits::zero(Sign::POS).get_val();
+    }
+  }
+
+  Sign result_sign = Sign::POS;
+
+  if (x_abs > y_abs)
+    result_sign = x_bits.sign();
+  else if (x_abs < y_abs)
+    result_sign = y_bits.sign();
+  else if (x_bits.sign() == y_bits.sign())
+    result_sign = x_bits.sign();
+
+  InFPBits max_bits(cpp::max(x_abs, y_abs));
+  InFPBits min_bits(cpp::min(x_abs, y_abs));
+
+  InStorageType result_mant;
+
+  if (max_bits.is_subnormal()) {
+    // min_bits must be subnormal too.
+    if (max_bits.sign() == min_bits.sign())
+      result_mant = max_bits.get_mantissa() + min_bits.get_mantissa();
+    else
+      result_mant = max_bits.get_mantissa() - min_bits.get_mantissa();
+
+    result_mant <<= GUARD_BITS_LEN;
+  } else {
+    InStorageType max_mant = max_bits.get_explicit_mantissa() << GUARD_BITS_LEN;
+    InStorageType min_mant = min_bits.get_explicit_mantissa() << GUARD_BITS_LEN;
+    int alignment =
+        max_bits.get_biased_exponent() - min_bits.get_biased_exponent();
+
+    InStorageType aligned_min_mant =
+        min_mant >> cpp::min(alignment, RESULT_MANTISSA_LEN);
+    bool aligned_min_mant_sticky;
+
+    if (alignment <= 3)
+      aligned_min_mant_sticky = false;
+    else if (alignment <= InFPBits::FRACTION_LEN + 3)
+      aligned_min_mant_sticky =
+          (min_mant << (InFPBits::STORAGE_LEN - alignment)) != 0;
+    else
+      aligned_min_mant_sticky = true;
+
+    if (max_bits.sign() == min_bits.sign())
+      result_mant = max_mant + (aligned_min_mant | aligned_min_mant_sticky);
+    else
+      result_mant = max_mant - (aligned_min_mant | aligned_min_mant_sticky);
+  }
+
+  int result_exp = max_bits.get_exponent() - RESULT_FRACTION_LEN;
+  DyadicFloat result(result_sign, result_exp, result_mant);
+  return result.template as<OutType, /*ShouldSignalExceptions=*/true>();
+}
+
+} // namespace LIBC_NAMESPACE::fputil::generic
+
+#endif // LLVM_LIBC_SRC___SUPPORT_FPUTIL_GENERIC_ADD_H
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index fb0d971e88733..128de57e9150a 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -99,6 +99,8 @@ add_math_entrypoint_object(exp10f)
 add_math_entrypoint_object(expm1)
 add_math_entrypoint_object(expm1f)
 
+add_math_entrypoint_object(f16addf)
+
 add_math_entrypoint_object(f16div)
 add_math_entrypoint_object(f16divf)
 add_math_entrypoint_object(f16divl)
diff --git a/libc/src/math/f16addf.h b/libc/src/math/f16addf.h
new file mode 100644
index 0000000000000..31d0e786584e6
--- /dev/null
+++ b/libc/src/math/f16addf.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for f16addf -----------------------*- 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_F16ADDF_H
+#define LLVM_LIBC_SRC_MATH_F16ADDF_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 f16addf(float x, float y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_F16ADDF_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 0e4893cd42ee1..f9e1797981f4a 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3776,6 +3776,19 @@ add_entrypoint_object(
     -O3
 )
 
+add_entrypoint_object(
+  f16addf
+  SRCS
+    f16addf.cpp
+  HDRS
+    ../f16addf.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.generic.add
+  COMPILE_OPTIONS
+    -O3
+)
+
 add_entrypoint_object(
   f16div
   SRCS
diff --git a/libc/src/math/generic/f16addf.cpp b/libc/src/math/generic/f16addf.cpp
new file mode 100644
index 0000000000000..de2f666cdc9fa
--- /dev/null
+++ b/libc/src/math/generic/f16addf.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of f16addf 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/f16addf.h"
+#include "src/__support/FPUtil/generic/add.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, f16addf, (float x, float y)) {
+  return fputil::generic::add<float16>(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/math/AddTest.h b/libc/test/src/math/AddTest.h
new file mode 100644
index 0000000000000..df0ef66cfeefa
--- /dev/null
+++ b/libc/test/src/math/AddTest.h
@@ -0,0 +1,74 @@
+//===-- Utility class to test different flavors of float add ----*- 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_TEST_SRC_MATH_ADDTEST_H
+#define LLVM_LIBC_TEST_SRC_MATH_ADDTEST_H
+
+#include "test/UnitTest/FEnvSafeTest.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+template <typename OutType, typename InType>
+class AddTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
+
+  struct InConstants {
+    DECLARE_SPECIAL_CONSTANTS(InType)
+  };
+
+  using InFPBits = typename InConstants::FPBits;
+  using InStorageType = typename InConstants::StorageType;
+
+  static constexpr InStorageType IN_MAX_NORMAL_U =
+      InFPBits::max_normal().uintval();
+  static constexpr InStorageType IN_MIN_NORMAL_U =
+      InFPBits::min_normal().uintval();
+  static constexpr InStorageType IN_MAX_SUBNORMAL_U =
+      InFPBits::max_subnormal().uintval();
+  static constexpr InStorageType IN_MIN_SUBNORMAL_U =
+      InFPBits::min_subnormal().uintval();
+
+public:
+  typedef OutType (*AddFunc)(InType, InType);
+
+  void test_subnormal_range(AddFunc func) {
+    constexpr InStorageType COUNT = 100'001;
+    constexpr InStorageType STEP =
+        (IN_MAX_SUBNORMAL_U - IN_MIN_SUBNORMAL_U) / COUNT;
+    for (InStorageType i = 0, v = 0, w = IN_MAX_SUBNORMAL_U; i <= COUNT;
+         ++i, v += STEP, w -= STEP) {
+      InType x = InFPBits(v).get_val();
+      InType y = InFPBits(w).get_val();
+      mpfr::BinaryInput<InType> input{x, y};
+      EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Add, input, func(x, y),
+                                     0.5);
+    }
+  }
+
+  void test_normal_range(AddFunc func) {
+    constexpr InStorageType COUNT = 100'001;
+    constexpr InStorageType STEP = (IN_MAX_NORMAL_U - IN_MIN_NORMAL_U) / COUNT;
+    for (InStorageType i = 0, v = 0, w = IN_MAX_NORMAL_U; i <= COUNT;
+         ++i, v += STEP, w -= STEP) {
+      InType x = InFPBits(v).get_val();
+      InType y = InFPBits(w).get_val();
+      mpfr::BinaryInput<InType> input{x, y};
+      EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Add, input, func(x, y),
+                                     0.5);
+    }
+  }
+};
+
+#define LIST_ADD_TESTS(OutType, InType, func)                                  \
+  using LlvmLibcAddTest = AddTest<OutType, InType>;                            \
+  TEST_F(LlvmLibcAddTest, SubnormalRange) { test_subnormal_range(&func); }     \
+  TEST_F(LlvmLibcAddTest, NormalRange) { test_normal_range(&func); }
+
+#endif // LLVM_LIBC_TEST_SRC_MATH_ADDTEST_H
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 061feeadb40d5..336313e8ae3f8 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1902,6 +1902,19 @@ add_fp_unittest(
     libc.src.__support.FPUtil.fp_bits
 )
 
+add_fp_unittest(
+  f16addf_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    f16addf_test.cpp
+  HDRS
+    AddTest.h
+  DEPENDS
+    libc.src.math.f16addf
+)
+
 add_fp_unittest(
   f16div_test
   NEED_MPFR
diff --git a/libc/test/src/math/f16addf_test.cpp b/libc/test/src/math/f16addf_test.cpp
new file mode 100644
index 0000000000000..1e8b4323114ad
--- /dev/null
+++ b/libc/test/src/math/f16addf_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16addf ---------------------------------------------===//
+//
+// 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 "AddTest.h"
+
+#include "src/math/f16addf.h"
+
+LIST_ADD_TESTS(float16, float, LIBC_NAMESPACE::f16addf)
diff --git a/libc/test/src/math/smoke/AddTest.h b/libc/test/src/math/smoke/AddTest.h
new file mode 100644
index 0000000000000..c713c5a88763c
--- /dev/null
+++ b/libc/test/src/math/smoke/AddTest.h
@@ -0,0 +1,156 @@
+//===-- Utility class to test different flavors of float add ----*- 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_TEST_SRC_MATH_SMOKE_ADDTEST_H
+#define LLVM_LIBC_TEST_SRC_MATH_SMOKE_ADDTEST_H
+
+#include "hdr/errno_macros.h"
+#include "hdr/fenv_macros.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "test/UnitTest/FEnvSafeTest.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+template <typename OutType, typename InType>
+class AddTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
+
+  DECLARE_SPECIAL_CONSTANTS(OutType)
+
+  struct InConstants {
+    DECLARE_SPECIAL_CONSTANTS(InType)
+  };
+
+  using InFPBits = typename InConstants::FPBits;
+  using InStorageType = typename InConstants::StorageType;
+
+  InConstants in;
+
+public:
+  using AddFunc = OutType (*)(InType, InType);
+
+  void test_special_numbers(AddFunc func) {
+    EXPECT_FP_IS_NAN(func(aNaN, aNaN));
+    EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(sNaN, sNaN), FE_INVALID);
+
+    InType qnan_42 = InFPBits::quiet_nan(Sign::POS, 0x42).get_val();
+    EXPECT_FP_EQ(InType(0x42.0p+0),
+                 LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, zero)));
+    EXPECT_FP_EQ(InType(0x42.0p+0),
+                 LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_42)));
+
+    if constexpr (sizeof(OutType) < sizeof(InType)) {
+      InStorageType max_payload = InFPBits::FRACTION_MASK >> 1;
+      InType qnan_max = InFPBits::quiet_nan(Sign::POS, max_payload).get_val();
+      EXPECT_FP_EQ(zero,
+                   LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, zero)));
+      EXPECT_FP_EQ(zero,
+                   LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_max)));
+      EXPECT_FP_EQ(InType(0x42.0p+0),
+                   LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, qnan_42)));
+      EXPECT_FP_EQ(InType(0x42.0p+0),
+                   LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, qnan_max)));
+    }
+
+    EXPECT_FP_EQ(inf, func(inf, zero));
+    EXPECT_FP_EQ(neg_inf, func(neg_inf, zero));
+    EXPECT_FP_EQ(inf, func(inf, neg_zero));
+    EXPECT_FP_EQ(neg_inf, func(neg_inf, neg_zero));
+  }
+
+  void test_invalid_operations(AddFunc func) {
+    EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(inf, neg_inf), FE_INVALID);
+    EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(neg_inf, inf), FE_INVALID);
+  }
+
+  void test_range_errors(AddFunc func) {
+    using namespace LIBC_NAMESPACE::fputil::testing;
+
+    if (ForceRoundingMode r(RoundingMode::Nearest); r.success) {
+      EXPECT_FP_EQ_WITH_EXCEPTION(inf, func(max_normal, max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(-inf, func(neg_max_normal, neg_max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+
+      EXPECT_FP_EQ_WITH_EXCEPTION(zero, func(in.min_denormal, in.min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(
+          neg_zero, func(in.neg_min_denormal, in.neg_min_denormal),
+          FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+    }
+
+    if (ForceRoundingMode r(RoundingMode::TowardZero); r.success) {
+      EXPECT_FP_EQ_WITH_EXCEPTION(max_normal, func(max_normal, max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_FP_EQ_WITH_EXCEPTION(neg_max_normal,
+                                  func(neg_max_normal, neg_max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+
+      EXPECT_FP_EQ_WITH_EXCEPTION(zero, func(in.min_denormal, in.min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(
+          neg_zero, func(in.neg_min_denormal, in.neg_min_denormal),
+          FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+    }
+
+    if (ForceRoundingMode r(RoundingMode::Downward); r.success) {
+      EXPECT_FP_EQ_WITH_EXCEPTION(max_normal, func(max_normal, max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_FP_EQ_WITH_EXCEPTION(-inf, func(neg_max_normal, neg_max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+
+      EXPECT_FP_EQ_WITH_EXCEPTION(zero, func(in.min_denormal, in.min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(
+          neg_min_denormal, func(in.neg_min_denormal, in.neg_min_denormal),
+          FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+    }
+
+    if (ForceRoundingMode r(RoundingMode::Upward); r.success) {
+      EXPECT_FP_EQ_WITH_EXCEPTION(inf, func(max_normal, max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(neg_max_normal,
+                                  func(neg_max_normal, neg_max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+
+      EXPECT_FP_EQ_WITH_EXCEPTION(min_denormal,
+                                  func(in.min_denormal, in.min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(
+          neg_zero, func(in.neg_min_denormal, in.neg_min_denormal),
+          FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+    }
+  }
+
+  void test_inexact_results(AddFunc func) {
+    func(InType(1.0), min_denormal);
+    EXPECT_FP_EXCEPTION(FE_INEXACT);
+  }
+};
+
+#define LIST_ADD_TESTS(OutType, InType, func)                                  \
+  using LlvmLibcAddTest = AddTest<OutType, InType>;                            \
+  TEST_F(LlvmLibcAddTest, SpecialNumbers) { test_special_numbers(&func); }     \
+  TEST_F(LlvmLibcAddTest, InvalidOperations) {                                 \
+    test_invalid_operations(&func);                                            \
+  }                                                                            \
+  TEST_F(LlvmLibcAddTest, RangeErrors) { test_range_errors(&func); }           \
+  TEST_F(LlvmLibcAddTest, InexactResults) { test_inexact_results(&func); }
+
+#endif // LLVM_LIBC_TEST_SRC_MATH_SMOKE_ADDTEST_H
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index e3d8a14191ad2..e509758bd353d 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3630,6 +3630,21 @@ add_fp_unittest(
     libc.src.math.setpayloadsigf16
 )
 
+add_fp_unittest(
+  f16addf_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    f16addf_test.cpp
+  HDRS
+    AddTest.h
+  DEPENDS
+    libc.hdr.errno_macros
+    libc.hdr.fenv_macros
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.math.f16addf
+)
+
 add_fp_unittest(
   f16div_test
   SUITE
diff --git a/libc/test/src/math/smoke/f16addf_test.cpp b/libc/test/src/math/smoke/f16addf_test.cpp
new file mode 100644
index 0000000000000..1e8b4323114ad
--- /dev/null
+++ b/libc/test/src/math/smoke/f16addf_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16addf ---------------------------------------------===//
+//
+// 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 "AddTest.h"
+
+#include "src/math/f16addf.h"
+
+LIST_ADD_TESTS(float16, float, LIBC_NAMESPACE::f16addf)
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.cpp b/libc/utils/MPFRWrapper/MPFRUtils.cpp
index 0bfe49984e7d2..d33526edd2289 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.cpp
+++ b/libc/utils/MPFRWrapper/MPFRUtils.cpp
@@ -188,6 +188,12 @@ class MPFRNumber {
     return result;
   }
 
+  MPFRNumber add(const MPFRNumber &b) const {
+    MPFRNumber result(*this);
+    mpfr_add(result.value, value, b.value, mpfr_rounding);
+    return result;
+  }
+
   MPFRNumber asin() const {
     MPFRNumber result(*this);
     mpfr_asin(result.value, value, mpfr_rounding);
@@ -712,6 +718,8 @@ binary_operation_one_output(Operation op, InputType x, InputType y,
   MPFRNumber inputX(x, precision, rounding);
   MPFRNumber inputY(y, precision, rounding);
   switch (op) {
+  case Operation::Add:
+    return inputX.add(inputY);
   case Operation::Atan2:
     return inputX.atan2(inputY);
   case Operation::Div:
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.h b/libc/utils/MPFRWrapper/MPFRUtils.h
index 46f3375fd4b7e..e96e5fd4795ef 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.h
+++ b/libc/utils/MPFRWrapper/MPFRUtils.h
@@ -70,6 +70,7 @@ enum class Operation : int {
   // input and produce a single floating point number of the same type as
   // output.
   BeginBinaryOperationsSingleOutput,
+  Add,
   Atan2,
   Div,
   Fmod,
@@ -303,7 +304,9 @@ constexpr bool is_valid_operation() {
       (op == Operation::Sqrt && cpp::is_floating_point_v<InputType> &&
        cpp::is_floating_point_v<OutputType> &&
        sizeof(OutputType) <= sizeof(InputType)) ||
-      (op == Operation::Div && internal::IsBinaryInput<InputType>::VALUE &&
+      (Operation::BeginBinaryOperationsSingleOutput < op &&
+       op < Operation::EndBinaryOperationsSingleOutput &&
+       internal::IsBinaryInput<InputType>::VALUE &&
        cpp::is_floating_point_v<
            typename internal::MakeScalarInput<InputType>::type> &&
        cpp::is_floating_point_v<OutputType>) ||

>From 85458273ef74d9a10b8dff28ee8a8eadd6916004 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Wed, 26 Jun 2024 16:00:00 +0200
Subject: [PATCH 02/12] [libc][math][c23] Add f16subf C23 math function

---
 libc/config/linux/aarch64/entrypoints.txt     |   1 +
 libc/config/linux/x86_64/entrypoints.txt      |   1 +
 libc/docs/math/index.rst                      |   2 +
 libc/spec/stdc.td                             |   2 +
 .../__support/FPUtil/generic/CMakeLists.txt   |   4 +-
 .../FPUtil/generic/{add.h => add_sub.h}       |  53 ++++--
 libc/src/math/CMakeLists.txt                  |   2 +
 libc/src/math/f16subf.h                       |  20 +++
 libc/src/math/generic/CMakeLists.txt          |  15 +-
 libc/src/math/generic/f16addf.cpp             |   2 +-
 libc/src/math/generic/f16subf.cpp             |  19 +++
 libc/test/src/math/CMakeLists.txt             |  13 ++
 libc/test/src/math/SubTest.h                  |  73 ++++++++
 libc/test/src/math/f16subf_test.cpp           |  13 ++
 libc/test/src/math/smoke/CMakeLists.txt       |  14 ++
 libc/test/src/math/smoke/SubTest.h            | 158 ++++++++++++++++++
 libc/test/src/math/smoke/f16subf_test.cpp     |  13 ++
 libc/utils/MPFRWrapper/MPFRUtils.cpp          |   8 +
 libc/utils/MPFRWrapper/MPFRUtils.h            |   1 +
 19 files changed, 396 insertions(+), 18 deletions(-)
 rename libc/src/__support/FPUtil/generic/{add.h => add_sub.h} (78%)
 create mode 100644 libc/src/math/f16subf.h
 create mode 100644 libc/src/math/generic/f16subf.cpp
 create mode 100644 libc/test/src/math/SubTest.h
 create mode 100644 libc/test/src/math/f16subf_test.cpp
 create mode 100644 libc/test/src/math/smoke/SubTest.h
 create mode 100644 libc/test/src/math/smoke/f16subf_test.cpp

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index aef77bbdf71b1..940c8ad010ff7 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -512,6 +512,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.f16divf
     libc.src.math.f16fmaf
     libc.src.math.f16sqrtf
+    libc.src.math.f16subf
     libc.src.math.fabsf16
     libc.src.math.fdimf16
     libc.src.math.floorf16
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index a806d22cc4417..0c1ae49fe99e1 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -545,6 +545,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.f16fmaf
     libc.src.math.f16fmal
     libc.src.math.f16sqrtf
+    libc.src.math.f16subf
     libc.src.math.fabsf16
     libc.src.math.fdimf16
     libc.src.math.floorf16
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 984addfc6a7a5..de3bc22477e85 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -130,6 +130,8 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16fma           | |check|          | |check|         | |check|                | N/A                  | |check|                | 7.12.14.5              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
+| f16sub           | |check|          |                 |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
++------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | fabs             | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.7.3               | F.10.4.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | fadd             | N/A              |                 |                        | N/A                  |                        | 7.12.14.1              | F.10.11                    |
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index b9ddc22ed445d..a49a70eecce1c 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -731,6 +731,8 @@ def StdC : StandardSpec<"stdc"> {
 
           GuardedFunctionSpec<"f16addf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
 
+          GuardedFunctionSpec<"f16subf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
+
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16sqrtf", RetValSpec<Float16Type>, [ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
diff --git a/libc/src/__support/FPUtil/generic/CMakeLists.txt b/libc/src/__support/FPUtil/generic/CMakeLists.txt
index 288169ea760bf..39a2458786073 100644
--- a/libc/src/__support/FPUtil/generic/CMakeLists.txt
+++ b/libc/src/__support/FPUtil/generic/CMakeLists.txt
@@ -49,9 +49,9 @@ add_header_library(
 )
 
 add_header_library(
-  add
+  add_sub
   HDRS
-    add.h
+    add_sub.h
   DEPENDS
     libc.hdr.errno_macros
     libc.hdr.fenv_macros
diff --git a/libc/src/__support/FPUtil/generic/add.h b/libc/src/__support/FPUtil/generic/add_sub.h
similarity index 78%
rename from libc/src/__support/FPUtil/generic/add.h
rename to libc/src/__support/FPUtil/generic/add_sub.h
index a987c38236396..1a632ff262408 100644
--- a/libc/src/__support/FPUtil/generic/add.h
+++ b/libc/src/__support/FPUtil/generic/add_sub.h
@@ -1,4 +1,4 @@
-//===-- Addition of IEEE 754 floating-point numbers -------------*- C++ -*-===//
+//===-- Add and subtract IEEE 754 floating-point numbers --------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -6,8 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC___SUPPORT_FPUTIL_GENERIC_ADD_H
-#define LLVM_LIBC_SRC___SUPPORT_FPUTIL_GENERIC_ADD_H
+#ifndef LLVM_LIBC_SRC___SUPPORT_FPUTIL_GENERIC_ADD_SUB_H
+#define LLVM_LIBC_SRC___SUPPORT_FPUTIL_GENERIC_ADD_SUB_H
 
 #include "hdr/errno_macros.h"
 #include "hdr/fenv_macros.h"
@@ -24,12 +24,12 @@
 
 namespace LIBC_NAMESPACE::fputil::generic {
 
-template <typename OutType, typename InType>
+template <bool IsSub, typename OutType, typename InType>
 LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<OutType> &&
                                  cpp::is_floating_point_v<InType> &&
                                  sizeof(OutType) <= sizeof(InType),
                              OutType>
-add(InType x, InType y) {
+add_or_sub(InType x, InType y) {
   using OutFPBits = FPBits<OutType>;
   using OutStorageType = typename OutFPBits::StorageType;
   using InFPBits = FPBits<InType>;
@@ -45,6 +45,8 @@ add(InType x, InType y) {
   InFPBits x_bits(x);
   InFPBits y_bits(y);
 
+  bool is_effectively_add = (x_bits.sign() == y_bits.sign()) ^ IsSub;
+
   if (LIBC_UNLIKELY(x_bits.is_inf_or_nan() || y_bits.is_inf_or_nan() ||
                     x_bits.is_zero() || y_bits.is_zero())) {
     if (x_bits.is_nan() || y_bits.is_nan()) {
@@ -72,7 +74,7 @@ add(InType x, InType y) {
 
     if (x_bits.is_inf()) {
       if (y_bits.is_inf()) {
-        if (x_bits.sign() != y_bits.sign()) {
+        if (!is_effectively_add) {
           raise_except_if_required(FE_INVALID);
           return OutFPBits::quiet_nan().get_val();
         }
@@ -106,7 +108,7 @@ add(InType x, InType y) {
   InType x_abs = x_bits.abs().get_val();
   InType y_abs = y_bits.abs().get_val();
 
-  if (x_abs == y_abs && x_bits.sign() != y_bits.sign()) {
+  if (x_abs == y_abs && !is_effectively_add) {
     switch (quick_get_round()) {
     case FE_DOWNWARD:
       return OutFPBits::zero(Sign::NEG).get_val();
@@ -117,12 +119,16 @@ add(InType x, InType y) {
 
   Sign result_sign = Sign::POS;
 
-  if (x_abs > y_abs)
+  if (x_abs > y_abs) {
     result_sign = x_bits.sign();
-  else if (x_abs < y_abs)
-    result_sign = y_bits.sign();
-  else if (x_bits.sign() == y_bits.sign())
+  } else if (x_abs < y_abs) {
+    if (is_effectively_add)
+      result_sign = y_bits.sign();
+    else if (y_bits.is_pos())
+      result_sign = Sign::NEG;
+  } else if (is_effectively_add) {
     result_sign = x_bits.sign();
+  }
 
   InFPBits max_bits(cpp::max(x_abs, y_abs));
   InFPBits min_bits(cpp::min(x_abs, y_abs));
@@ -131,7 +137,8 @@ add(InType x, InType y) {
 
   if (max_bits.is_subnormal()) {
     // min_bits must be subnormal too.
-    if (max_bits.sign() == min_bits.sign())
+
+    if (is_effectively_add)
       result_mant = max_bits.get_mantissa() + min_bits.get_mantissa();
     else
       result_mant = max_bits.get_mantissa() - min_bits.get_mantissa();
@@ -155,7 +162,7 @@ add(InType x, InType y) {
     else
       aligned_min_mant_sticky = true;
 
-    if (max_bits.sign() == min_bits.sign())
+    if (is_effectively_add)
       result_mant = max_mant + (aligned_min_mant | aligned_min_mant_sticky);
     else
       result_mant = max_mant - (aligned_min_mant | aligned_min_mant_sticky);
@@ -166,6 +173,24 @@ add(InType x, InType y) {
   return result.template as<OutType, /*ShouldSignalExceptions=*/true>();
 }
 
+template <typename OutType, typename InType>
+LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<OutType> &&
+                                 cpp::is_floating_point_v<InType> &&
+                                 sizeof(OutType) <= sizeof(InType),
+                             OutType>
+add(InType x, InType y) {
+  return add_or_sub</*IsSub=*/false, OutType>(x, y);
+}
+
+template <typename OutType, typename InType>
+LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<OutType> &&
+                                 cpp::is_floating_point_v<InType> &&
+                                 sizeof(OutType) <= sizeof(InType),
+                             OutType>
+sub(InType x, InType y) {
+  return add_or_sub</*IsSub=*/true, OutType>(x, y);
+}
+
 } // namespace LIBC_NAMESPACE::fputil::generic
 
-#endif // LLVM_LIBC_SRC___SUPPORT_FPUTIL_GENERIC_ADD_H
+#endif // LLVM_LIBC_SRC___SUPPORT_FPUTIL_GENERIC_ADD_SUB_H
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 128de57e9150a..6ab630adefde9 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -113,6 +113,8 @@ add_math_entrypoint_object(f16fmaf128)
 
 add_math_entrypoint_object(f16sqrtf)
 
+add_math_entrypoint_object(f16subf)
+
 add_math_entrypoint_object(fabs)
 add_math_entrypoint_object(fabsf)
 add_math_entrypoint_object(fabsl)
diff --git a/libc/src/math/f16subf.h b/libc/src/math/f16subf.h
new file mode 100644
index 0000000000000..1d04a4c952d17
--- /dev/null
+++ b/libc/src/math/f16subf.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for f16subf -----------------------*- 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_F16SUBF_H
+#define LLVM_LIBC_SRC_MATH_F16SUBF_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 f16subf(float x, float y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_F16SUBF_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index f9e1797981f4a..7e2d46fdb68b9 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3784,7 +3784,20 @@ add_entrypoint_object(
     ../f16addf.h
   DEPENDS
     libc.src.__support.macros.properties.types
-    libc.src.__support.FPUtil.generic.add
+    libc.src.__support.FPUtil.generic.add_sub
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
+  f16subf
+  SRCS
+    f16subf.cpp
+  HDRS
+    ../f16subf.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.generic.add_sub
   COMPILE_OPTIONS
     -O3
 )
diff --git a/libc/src/math/generic/f16addf.cpp b/libc/src/math/generic/f16addf.cpp
index de2f666cdc9fa..f1761a193985d 100644
--- a/libc/src/math/generic/f16addf.cpp
+++ b/libc/src/math/generic/f16addf.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/f16addf.h"
-#include "src/__support/FPUtil/generic/add.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
 #include "src/__support/common.h"
 
 namespace LIBC_NAMESPACE {
diff --git a/libc/src/math/generic/f16subf.cpp b/libc/src/math/generic/f16subf.cpp
new file mode 100644
index 0000000000000..e4532a456b7b8
--- /dev/null
+++ b/libc/src/math/generic/f16subf.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of f16subf 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/f16subf.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, f16subf, (float x, float y)) {
+  return fputil::generic::sub<float16>(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 336313e8ae3f8..5453db02493ff 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1915,6 +1915,19 @@ add_fp_unittest(
     libc.src.math.f16addf
 )
 
+add_fp_unittest(
+  f16subf_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    f16subf_test.cpp
+  HDRS
+    SubTest.h
+  DEPENDS
+    libc.src.math.f16subf
+)
+
 add_fp_unittest(
   f16div_test
   NEED_MPFR
diff --git a/libc/test/src/math/SubTest.h b/libc/test/src/math/SubTest.h
new file mode 100644
index 0000000000000..2d1e475a9b538
--- /dev/null
+++ b/libc/test/src/math/SubTest.h
@@ -0,0 +1,73 @@
+//===-- Utility class to test different flavors of float sub ----*- 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_TEST_SRC_MATH_SUBTEST_H
+#define LLVM_LIBC_TEST_SRC_MATH_SUBTEST_H
+
+#include "test/UnitTest/FEnvSafeTest.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+template <typename OutType, typename InType>
+class SubTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
+
+  struct InConstants {
+    DECLARE_SPECIAL_CONSTANTS(InType)
+  };
+
+  using InFPBits = typename InConstants::FPBits;
+  using InStorageType = typename InConstants::StorageType;
+
+  static constexpr InStorageType IN_MAX_NORMAL_U =
+      InFPBits::max_normal().uintval();
+  static constexpr InStorageType IN_MIN_NORMAL_U =
+      InFPBits::min_normal().uintval();
+  static constexpr InStorageType IN_MAX_SUBNORMAL_U =
+      InFPBits::max_subnormal().uintval();
+  static constexpr InStorageType IN_MIN_SUBNORMAL_U =
+      InFPBits::min_subnormal().uintval();
+
+public:
+  typedef OutType (*AddFunc)(InType, InType);
+
+  void test_subnormal_range(AddFunc func) {
+    constexpr InStorageType STEP =
+        (IN_MAX_SUBNORMAL_U - IN_MIN_SUBNORMAL_U) / COUNT;
+    for (InStorageType i = 0, v = 0, w = IN_MAX_SUBNORMAL_U; i <= COUNT;
+         ++i, v += STEP, w -= STEP) {
+      InType x = InFPBits(v).get_val();
+      InType y = InFPBits(w).get_val();
+      mpfr::BinaryInput<InType> input{x, y};
+      EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Sub, input, func(x, y),
+                                     0.5);
+    }
+  }
+
+  void test_normal_range(AddFunc func) {
+    constexpr InStorageType COUNT = 100'001;
+    constexpr InStorageType STEP = (IN_MAX_NORMAL_U - IN_MIN_NORMAL_U) / COUNT;
+    for (InStorageType i = 0, v = 0, w = IN_MAX_NORMAL_U; i <= COUNT;
+         ++i, v += STEP, w -= STEP) {
+      InType x = InFPBits(v).get_val();
+      InType y = InFPBits(w).get_val();
+      mpfr::BinaryInput<InType> input{x, y};
+      EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Sub, input, func(x, y),
+                                     0.5);
+    }
+  }
+};
+
+#define LIST_SUB_TESTS(OutType, InType, func)                                  \
+  using LlvmLibcSubTest = SubTest<OutType, InType>;                            \
+  TEST_F(LlvmLibcSubTest, SubnormalRange) { test_subnormal_range(&func); }     \
+  TEST_F(LlvmLibcSubTest, NormalRange) { test_normal_range(&func); }
+
+#endif // LLVM_LIBC_TEST_SRC_MATH_ADDTEST_H
diff --git a/libc/test/src/math/f16subf_test.cpp b/libc/test/src/math/f16subf_test.cpp
new file mode 100644
index 0000000000000..68ad9482ab1e4
--- /dev/null
+++ b/libc/test/src/math/f16subf_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16subf ---------------------------------------------===//
+//
+// 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 "SubTest.h"
+
+#include "src/math/f16subf.h"
+
+LIST_SUB_TESTS(float16, float, LIBC_NAMESPACE::f16subf)
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index e509758bd353d..d453a7c38bed9 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3645,6 +3645,20 @@ add_fp_unittest(
     libc.src.math.f16addf
 )
 
+add_fp_unittest(
+  f16subf_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    f16subf_test.cpp
+  HDRS
+    SubTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.math.f16subf
+)
+
 add_fp_unittest(
   f16div_test
   SUITE
diff --git a/libc/test/src/math/smoke/SubTest.h b/libc/test/src/math/smoke/SubTest.h
new file mode 100644
index 0000000000000..b7d62b109b8a9
--- /dev/null
+++ b/libc/test/src/math/smoke/SubTest.h
@@ -0,0 +1,158 @@
+//===-- Utility class to test different flavors of float sub ----*- 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_TEST_SRC_MATH_SMOKE_SUBTEST_H
+#define LLVM_LIBC_TEST_SRC_MATH_SMOKE_SUBTEST_H
+
+#include "hdr/fenv_macros.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "test/UnitTest/FEnvSafeTest.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+template <typename OutType, typename InType>
+class SubTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
+
+  DECLARE_SPECIAL_CONSTANTS(OutType)
+
+  struct InConstants {
+    DECLARE_SPECIAL_CONSTANTS(InType)
+  };
+
+  using InFPBits = typename InConstants::FPBits;
+  using InStorageType = typename InConstants::StorageType;
+
+  InConstants in;
+
+public:
+  using SubFunc = OutType (*)(InType, InType);
+
+  void test_special_numbers(SubFunc func) {
+    EXPECT_FP_IS_NAN(func(aNaN, aNaN));
+    EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(sNaN, sNaN), FE_INVALID);
+
+    InType qnan_42 = InFPBits::quiet_nan(Sign::POS, 0x42).get_val();
+    EXPECT_FP_EQ(InType(0x42.0p+0),
+                 LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, zero)));
+    EXPECT_FP_EQ(InType(0x42.0p+0),
+                 LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_42)));
+
+    if constexpr (sizeof(OutType) < sizeof(InType)) {
+      InStorageType max_payload = InFPBits::FRACTION_MASK >> 1;
+      InType qnan_max = InFPBits::quiet_nan(Sign::POS, max_payload).get_val();
+      EXPECT_FP_EQ(zero,
+                   LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, zero)));
+      EXPECT_FP_EQ(zero,
+                   LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_max)));
+      EXPECT_FP_EQ(InType(0x42.0p+0),
+                   LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, qnan_42)));
+      EXPECT_FP_EQ(InType(0x42.0p+0),
+                   LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, qnan_max)));
+    }
+
+    EXPECT_FP_EQ(inf, func(inf, zero));
+    EXPECT_FP_EQ(neg_inf, func(neg_inf, zero));
+    EXPECT_FP_EQ(inf, func(inf, neg_zero));
+    EXPECT_FP_EQ(neg_inf, func(neg_inf, neg_zero));
+  }
+
+  void test_invalid_operations(SubFunc func) {
+    EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(inf, inf), FE_INVALID);
+    EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(neg_inf, neg_inf), FE_INVALID);
+  }
+
+  void test_range_errors(SubFunc func) {
+    using namespace LIBC_NAMESPACE::fputil::testing;
+
+    if (ForceRoundingMode r(RoundingMode::Nearest); r.success) {
+      EXPECT_FP_EQ_WITH_EXCEPTION(inf, func(max_normal, neg_max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(-inf, func(neg_max_normal, max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+
+      EXPECT_FP_EQ_WITH_EXCEPTION(zero,
+                                  func(in.min_denormal, in.neg_min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(neg_zero,
+                                  func(in.neg_min_denormal, in.min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+    }
+
+    if (ForceRoundingMode r(RoundingMode::TowardZero); r.success) {
+      EXPECT_FP_EQ_WITH_EXCEPTION(max_normal, func(max_normal, neg_max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_FP_EQ_WITH_EXCEPTION(neg_max_normal,
+                                  func(neg_max_normal, max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+
+      EXPECT_FP_EQ_WITH_EXCEPTION(zero,
+                                  func(in.min_denormal, in.neg_min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(neg_zero,
+                                  func(in.neg_min_denormal, in.min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+    }
+
+    if (ForceRoundingMode r(RoundingMode::Downward); r.success) {
+      EXPECT_FP_EQ_WITH_EXCEPTION(max_normal, func(max_normal, neg_max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_FP_EQ_WITH_EXCEPTION(-inf, func(neg_max_normal, max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+
+      EXPECT_FP_EQ_WITH_EXCEPTION(zero,
+                                  func(in.min_denormal, in.neg_min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(neg_min_denormal,
+                                  func(in.neg_min_denormal, in.min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+    }
+
+    if (ForceRoundingMode r(RoundingMode::Upward); r.success) {
+      EXPECT_FP_EQ_WITH_EXCEPTION(inf, func(max_normal, neg_max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(neg_max_normal,
+                                  func(neg_max_normal, max_normal),
+                                  FE_OVERFLOW | FE_INEXACT);
+
+      EXPECT_FP_EQ_WITH_EXCEPTION(min_denormal,
+                                  func(in.min_denormal, in.neg_min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+      EXPECT_FP_EQ_WITH_EXCEPTION(neg_zero,
+                                  func(in.neg_min_denormal, in.min_denormal),
+                                  FE_UNDERFLOW | FE_INEXACT);
+      EXPECT_MATH_ERRNO(ERANGE);
+    }
+  }
+
+  void test_inexact_results(SubFunc func) {
+    func(InType(1.0), min_denormal);
+    EXPECT_FP_EXCEPTION(FE_INEXACT);
+  }
+};
+
+#define LIST_SUB_TESTS(OutType, InType, func)                                  \
+  using LlvmLibcSubTest = SubTest<OutType, InType>;                            \
+  TEST_F(LlvmLibcSubTest, SpecialNumbers) { test_special_numbers(&func); }     \
+  TEST_F(LlvmLibcSubTest, InvalidOperations) {                                 \
+    test_invalid_operations(&func);                                            \
+  }                                                                            \
+  TEST_F(LlvmLibcSubTest, RangeErrors) { test_range_errors(&func); }           \
+  TEST_F(LlvmLibcSubTest, InexactResults) { test_inexact_results(&func); }
+
+#endif // LLVM_LIBC_TEST_SRC_MATH_SMOKE_ADDTEST_H
diff --git a/libc/test/src/math/smoke/f16subf_test.cpp b/libc/test/src/math/smoke/f16subf_test.cpp
new file mode 100644
index 0000000000000..68ad9482ab1e4
--- /dev/null
+++ b/libc/test/src/math/smoke/f16subf_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16subf ---------------------------------------------===//
+//
+// 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 "SubTest.h"
+
+#include "src/math/f16subf.h"
+
+LIST_SUB_TESTS(float16, float, LIBC_NAMESPACE::f16subf)
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.cpp b/libc/utils/MPFRWrapper/MPFRUtils.cpp
index d33526edd2289..a0888a5c480e9 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.cpp
+++ b/libc/utils/MPFRWrapper/MPFRUtils.cpp
@@ -455,6 +455,12 @@ class MPFRNumber {
     return result;
   }
 
+  MPFRNumber sub(const MPFRNumber &b) const {
+    MPFRNumber result(*this);
+    mpfr_sub(result.value, value, b.value, mpfr_rounding);
+    return result;
+  }
+
   MPFRNumber tan() const {
     MPFRNumber result(*this);
     mpfr_tan(result.value, value, mpfr_rounding);
@@ -730,6 +736,8 @@ binary_operation_one_output(Operation op, InputType x, InputType y,
     return inputX.hypot(inputY);
   case Operation::Pow:
     return inputX.pow(inputY);
+  case Operation::Sub:
+    return inputX.sub(inputY);
   default:
     __builtin_unreachable();
   }
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.h b/libc/utils/MPFRWrapper/MPFRUtils.h
index e96e5fd4795ef..d8f96d4cfe6e4 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.h
+++ b/libc/utils/MPFRWrapper/MPFRUtils.h
@@ -76,6 +76,7 @@ enum class Operation : int {
   Fmod,
   Hypot,
   Pow,
+  Sub,
   EndBinaryOperationsSingleOutput,
 
   // Operations which take two floating point numbers of the same type as

>From 311a349ea48661ab764244df7a94eeed8d453c0e Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Thu, 27 Jun 2024 15:28:18 +0200
Subject: [PATCH 03/12] fixup! [libc][math][c23] Add f16subf C23 math function

---
 libc/test/src/math/SubTest.h       | 9 +++++----
 libc/test/src/math/smoke/SubTest.h | 2 +-
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/libc/test/src/math/SubTest.h b/libc/test/src/math/SubTest.h
index 2d1e475a9b538..9b4035344b468 100644
--- a/libc/test/src/math/SubTest.h
+++ b/libc/test/src/math/SubTest.h
@@ -36,9 +36,10 @@ class SubTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
       InFPBits::min_subnormal().uintval();
 
 public:
-  typedef OutType (*AddFunc)(InType, InType);
+  using SubFunc = OutType (*)(InType, InType);
 
-  void test_subnormal_range(AddFunc func) {
+  void test_subnormal_range(SubFunc func) {
+    constexpr InStorageType COUNT = 100'001;
     constexpr InStorageType STEP =
         (IN_MAX_SUBNORMAL_U - IN_MIN_SUBNORMAL_U) / COUNT;
     for (InStorageType i = 0, v = 0, w = IN_MAX_SUBNORMAL_U; i <= COUNT;
@@ -51,7 +52,7 @@ class SubTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
     }
   }
 
-  void test_normal_range(AddFunc func) {
+  void test_normal_range(SubFunc func) {
     constexpr InStorageType COUNT = 100'001;
     constexpr InStorageType STEP = (IN_MAX_NORMAL_U - IN_MIN_NORMAL_U) / COUNT;
     for (InStorageType i = 0, v = 0, w = IN_MAX_NORMAL_U; i <= COUNT;
@@ -70,4 +71,4 @@ class SubTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
   TEST_F(LlvmLibcSubTest, SubnormalRange) { test_subnormal_range(&func); }     \
   TEST_F(LlvmLibcSubTest, NormalRange) { test_normal_range(&func); }
 
-#endif // LLVM_LIBC_TEST_SRC_MATH_ADDTEST_H
+#endif // LLVM_LIBC_TEST_SRC_MATH_SUBTEST_H
diff --git a/libc/test/src/math/smoke/SubTest.h b/libc/test/src/math/smoke/SubTest.h
index b7d62b109b8a9..a4b3822aca43c 100644
--- a/libc/test/src/math/smoke/SubTest.h
+++ b/libc/test/src/math/smoke/SubTest.h
@@ -155,4 +155,4 @@ class SubTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
   TEST_F(LlvmLibcSubTest, RangeErrors) { test_range_errors(&func); }           \
   TEST_F(LlvmLibcSubTest, InexactResults) { test_inexact_results(&func); }
 
-#endif // LLVM_LIBC_TEST_SRC_MATH_SMOKE_ADDTEST_H
+#endif // LLVM_LIBC_TEST_SRC_MATH_SMOKE_SUBTEST_H

>From 08ac73838948c942090e91fa01a6cc8e0bf6d669 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Fri, 28 Jun 2024 14:35:07 +0200
Subject: [PATCH 04/12] fixup! [libc][math][c23] Add f16subf C23 math function

Fix double rounding error.
---
 libc/src/__support/FPUtil/generic/add_sub.h | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/libc/src/__support/FPUtil/generic/add_sub.h b/libc/src/__support/FPUtil/generic/add_sub.h
index 1a632ff262408..6d640026e2927 100644
--- a/libc/src/__support/FPUtil/generic/add_sub.h
+++ b/libc/src/__support/FPUtil/generic/add_sub.h
@@ -98,11 +98,21 @@ add_or_sub(InType x, InType y) {
         }
       }
 
-      return static_cast<OutType>(y);
+      // volatile prevents Clang from converting tmp to OutType and then
+      // immediately back to InType before negating it, resulting in double
+      // rounding.
+      volatile InType tmp = y;
+      if constexpr (IsSub)
+        tmp = -tmp;
+      return static_cast<OutType>(tmp);
     }
 
-    if (y_bits.is_zero())
-      return static_cast<OutType>(x);
+    if (y_bits.is_zero()) {
+      volatile InType tmp = y;
+      if constexpr (IsSub)
+        tmp = -tmp;
+      return static_cast<OutType>(tmp);
+    }
   }
 
   InType x_abs = x_bits.abs().get_val();

>From 597a713ac766310839184cfb32bc7a5dc0bceffd Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Sun, 30 Jun 2024 01:30:10 +0200
Subject: [PATCH 05/12] [libc][math][c23] Move f16{add,sub}f specs to
 llvm_libc_ext.td

---
 libc/docs/math/index.rst   | 4 ++--
 libc/spec/llvm_libc_ext.td | 4 ++++
 libc/spec/stdc.td          | 4 ----
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index de3bc22477e85..c0bfb9a482fe4 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -124,13 +124,13 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | dsub             | N/A              | N/A             |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16add           | |check|          |                 |                        | N/A                  |                        | 7.12.14.1              | F.10.11                    |
+| f16add           | |check|\*        |                 |                        | N/A                  |                        | 7.12.14.1              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16div           | |check|\*        | |check|\*       | |check|\*              | N/A                  | |check|                | 7.12.14.4              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16fma           | |check|          | |check|         | |check|                | N/A                  | |check|                | 7.12.14.5              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16sub           | |check|          |                 |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
+| f16sub           | |check|\*        |                 |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | fabs             | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.7.3               | F.10.4.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/llvm_libc_ext.td b/libc/spec/llvm_libc_ext.td
index ed1a17ec91904..24dfca9befe36 100644
--- a/libc/spec/llvm_libc_ext.td
+++ b/libc/spec/llvm_libc_ext.td
@@ -57,6 +57,10 @@ def LLVMLibcExt : StandardSpec<"llvm_libc_ext"> {
       [], // Types
       [], // Enumerations
       [
+          GuardedFunctionSpec<"f16addf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
+
+          GuardedFunctionSpec<"f16subf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
+
           GuardedFunctionSpec<"f16div", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16divf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16divl", RetValSpec<Float16Type>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index a49a70eecce1c..481515ad439ed 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -729,10 +729,6 @@ def StdC : StandardSpec<"stdc"> {
 
           GuardedFunctionSpec<"setpayloadsigf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
-          GuardedFunctionSpec<"f16addf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
-
-          GuardedFunctionSpec<"f16subf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
-
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16sqrtf", RetValSpec<Float16Type>, [ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,

>From 84183b27e6bf0739a3d236f9f35891e098b938b0 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Fri, 28 Jun 2024 16:56:43 +0200
Subject: [PATCH 06/12] [libc][math][c23] Add f16add C23 math function

---
 libc/config/linux/aarch64/entrypoints.txt |  1 +
 libc/config/linux/x86_64/entrypoints.txt  |  1 +
 libc/docs/math/index.rst                  |  2 +-
 libc/spec/stdc.td                         |  2 ++
 libc/src/math/CMakeLists.txt              |  1 +
 libc/src/math/f16add.h                    | 20 ++++++++++++++++++++
 libc/src/math/generic/CMakeLists.txt      | 13 +++++++++++++
 libc/src/math/generic/f16add.cpp          | 19 +++++++++++++++++++
 libc/test/src/math/CMakeLists.txt         | 13 +++++++++++++
 libc/test/src/math/f16add_test.cpp        | 13 +++++++++++++
 libc/test/src/math/smoke/CMakeLists.txt   | 15 +++++++++++++++
 libc/test/src/math/smoke/f16add_test.cpp  | 13 +++++++++++++
 12 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 libc/src/math/f16add.h
 create mode 100644 libc/src/math/generic/f16add.cpp
 create mode 100644 libc/test/src/math/f16add_test.cpp
 create mode 100644 libc/test/src/math/smoke/f16add_test.cpp

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 940c8ad010ff7..ac3c5e2cbdcc4 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -507,6 +507,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.canonicalizef16
     libc.src.math.ceilf16
     libc.src.math.copysignf16
+    libc.src.math.f16add
     libc.src.math.f16addf
     libc.src.math.f16div
     libc.src.math.f16divf
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 0c1ae49fe99e1..7d6876f000e79 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -537,6 +537,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.canonicalizef16
     libc.src.math.ceilf16
     libc.src.math.copysignf16
+    libc.src.math.f16add
     libc.src.math.f16addf
     libc.src.math.f16div
     libc.src.math.f16divf
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index c0bfb9a482fe4..a40941bc99b0e 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -124,7 +124,7 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | dsub             | N/A              | N/A             |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16add           | |check|\*        |                 |                        | N/A                  |                        | 7.12.14.1              | F.10.11                    |
+| f16add           | |check|\*        | |check|         |                        | N/A                  |                        | 7.12.14.1              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16div           | |check|\*        | |check|\*       | |check|\*              | N/A                  | |check|                | 7.12.14.4              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 481515ad439ed..24329c0f1797b 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -729,6 +729,8 @@ def StdC : StandardSpec<"stdc"> {
 
           GuardedFunctionSpec<"setpayloadsigf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
+          GuardedFunctionSpec<"f16add", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
+
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16sqrtf", RetValSpec<Float16Type>, [ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 6ab630adefde9..d08b3a04c45f4 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -99,6 +99,7 @@ add_math_entrypoint_object(exp10f)
 add_math_entrypoint_object(expm1)
 add_math_entrypoint_object(expm1f)
 
+add_math_entrypoint_object(f16add)
 add_math_entrypoint_object(f16addf)
 
 add_math_entrypoint_object(f16div)
diff --git a/libc/src/math/f16add.h b/libc/src/math/f16add.h
new file mode 100644
index 0000000000000..763a0787d860d
--- /dev/null
+++ b/libc/src/math/f16add.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for f16add ------------------------*- 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_F16ADD_H
+#define LLVM_LIBC_SRC_MATH_F16ADD_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 f16add(double x, double y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_F16ADD_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 7e2d46fdb68b9..2666303430798 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3776,6 +3776,19 @@ add_entrypoint_object(
     -O3
 )
 
+add_entrypoint_object(
+  f16add
+  SRCS
+    f16add.cpp
+  HDRS
+    ../f16add.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.generic.add_sub
+  COMPILE_OPTIONS
+    -O3
+)
+
 add_entrypoint_object(
   f16addf
   SRCS
diff --git a/libc/src/math/generic/f16add.cpp b/libc/src/math/generic/f16add.cpp
new file mode 100644
index 0000000000000..ef9b43e9f46aa
--- /dev/null
+++ b/libc/src/math/generic/f16add.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of f16add 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/f16add.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, f16add, (double x, double y)) {
+  return fputil::generic::add<float16>(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 5453db02493ff..9abe3f48ea0f7 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1902,6 +1902,19 @@ add_fp_unittest(
     libc.src.__support.FPUtil.fp_bits
 )
 
+add_fp_unittest(
+  f16add_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    f16add_test.cpp
+  HDRS
+    AddTest.h
+  DEPENDS
+    libc.src.math.f16add
+)
+
 add_fp_unittest(
   f16addf_test
   NEED_MPFR
diff --git a/libc/test/src/math/f16add_test.cpp b/libc/test/src/math/f16add_test.cpp
new file mode 100644
index 0000000000000..c47ece2a92555
--- /dev/null
+++ b/libc/test/src/math/f16add_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16add ----------------------------------------------===//
+//
+// 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 "AddTest.h"
+
+#include "src/math/f16add.h"
+
+LIST_ADD_TESTS(float16, double, LIBC_NAMESPACE::f16add)
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index d453a7c38bed9..e5c68f2274536 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3630,6 +3630,21 @@ add_fp_unittest(
     libc.src.math.setpayloadsigf16
 )
 
+add_fp_unittest(
+  f16add_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    f16add_test.cpp
+  HDRS
+    AddTest.h
+  DEPENDS
+    libc.hdr.errno_macros
+    libc.hdr.fenv_macros
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.math.f16add
+)
+
 add_fp_unittest(
   f16addf_test
   SUITE
diff --git a/libc/test/src/math/smoke/f16add_test.cpp b/libc/test/src/math/smoke/f16add_test.cpp
new file mode 100644
index 0000000000000..c47ece2a92555
--- /dev/null
+++ b/libc/test/src/math/smoke/f16add_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16add ----------------------------------------------===//
+//
+// 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 "AddTest.h"
+
+#include "src/math/f16add.h"
+
+LIST_ADD_TESTS(float16, double, LIBC_NAMESPACE::f16add)

>From fbc2d30abdb4d227b020cb35cc843391693de003 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Fri, 28 Jun 2024 17:01:13 +0200
Subject: [PATCH 07/12] [libc][math][c23] Add f16addf128 C23 math function

---
 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/f16addf128.h                   | 20 ++++++++++++++++++++
 libc/src/math/generic/CMakeLists.txt         | 13 +++++++++++++
 libc/src/math/generic/f16addf128.cpp         | 19 +++++++++++++++++++
 libc/test/src/math/smoke/CMakeLists.txt      | 15 +++++++++++++++
 libc/test/src/math/smoke/f16addf128_test.cpp | 13 +++++++++++++
 9 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 libc/src/math/f16addf128.h
 create mode 100644 libc/src/math/generic/f16addf128.cpp
 create mode 100644 libc/test/src/math/smoke/f16addf128_test.cpp

diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 7d6876f000e79..8b4018116d9e0 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -599,6 +599,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
   if(LIBC_TYPES_HAS_FLOAT128)
     list(APPEND TARGET_LIBM_ENTRYPOINTS
       # math.h C23 mixed _Float16 and _Float128 entrypoints
+      libc.src.math.f16addf128
       libc.src.math.f16fmaf128
       libc.src.math.f16divf128
     )
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index a40941bc99b0e..572a4f0ec0bb8 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -124,7 +124,7 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | dsub             | N/A              | N/A             |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16add           | |check|\*        | |check|         |                        | N/A                  |                        | 7.12.14.1              | F.10.11                    |
+| f16add           | |check|\*        | |check|         |                        | N/A                  | |check|                | 7.12.14.1              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16div           | |check|\*        | |check|\*       | |check|\*              | N/A                  | |check|                | 7.12.14.4              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 24329c0f1797b..0a03d83c85644 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -730,6 +730,7 @@ def StdC : StandardSpec<"stdc"> {
           GuardedFunctionSpec<"setpayloadsigf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
           GuardedFunctionSpec<"f16add", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
+          GuardedFunctionSpec<"f16addf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index d08b3a04c45f4..84deaf7de4cd6 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -101,6 +101,7 @@ add_math_entrypoint_object(expm1f)
 
 add_math_entrypoint_object(f16add)
 add_math_entrypoint_object(f16addf)
+add_math_entrypoint_object(f16addf128)
 
 add_math_entrypoint_object(f16div)
 add_math_entrypoint_object(f16divf)
diff --git a/libc/src/math/f16addf128.h b/libc/src/math/f16addf128.h
new file mode 100644
index 0000000000000..284ce1d303775
--- /dev/null
+++ b/libc/src/math/f16addf128.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for f16addf128 --------------------*- 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_F16ADDF128_H
+#define LLVM_LIBC_SRC_MATH_F16ADDF128_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 f16addf128(float128 x, float128 y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_F16ADDF128_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 2666303430798..a0b1a88ceab1a 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3802,6 +3802,19 @@ add_entrypoint_object(
     -O3
 )
 
+add_entrypoint_object(
+  f16addf128
+  SRCS
+    f16addf128.cpp
+  HDRS
+    ../f16addf128.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.generic.add_sub
+  COMPILE_OPTIONS
+    -O3
+)
+
 add_entrypoint_object(
   f16subf
   SRCS
diff --git a/libc/src/math/generic/f16addf128.cpp b/libc/src/math/generic/f16addf128.cpp
new file mode 100644
index 0000000000000..61c458f7d5de1
--- /dev/null
+++ b/libc/src/math/generic/f16addf128.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of f16addf128 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/f16addf128.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, f16addf128, (float128 x, float128 y)) {
+  return fputil::generic::add<float16>(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index e5c68f2274536..3b00abb2363f3 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3660,6 +3660,21 @@ add_fp_unittest(
     libc.src.math.f16addf
 )
 
+add_fp_unittest(
+  f16addf128_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    f16addf128_test.cpp
+  HDRS
+    AddTest.h
+  DEPENDS
+    libc.hdr.errno_macros
+    libc.hdr.fenv_macros
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.math.f16addf128
+)
+
 add_fp_unittest(
   f16subf_test
   SUITE
diff --git a/libc/test/src/math/smoke/f16addf128_test.cpp b/libc/test/src/math/smoke/f16addf128_test.cpp
new file mode 100644
index 0000000000000..8ed123b4ff1e8
--- /dev/null
+++ b/libc/test/src/math/smoke/f16addf128_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16addf128 ------------------------------------------===//
+//
+// 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 "AddTest.h"
+
+#include "src/math/f16addf128.h"
+
+LIST_ADD_TESTS(float16, float128, LIBC_NAMESPACE::f16addf128)

>From 9412cff1582bee48c86586dd4a39bc4394af8908 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Fri, 28 Jun 2024 17:16:09 +0200
Subject: [PATCH 08/12] [libc][math][c23] Add f16addl C23 math function

---
 libc/config/linux/x86_64/entrypoints.txt  |  3 ++-
 libc/docs/math/index.rst                  |  2 +-
 libc/spec/stdc.td                         |  1 +
 libc/src/math/CMakeLists.txt              |  1 +
 libc/src/math/f16addl.h                   | 20 ++++++++++++++++++++
 libc/src/math/generic/CMakeLists.txt      | 13 +++++++++++++
 libc/src/math/generic/f16addl.cpp         | 19 +++++++++++++++++++
 libc/test/src/math/CMakeLists.txt         | 13 +++++++++++++
 libc/test/src/math/f16addl_test.cpp       | 13 +++++++++++++
 libc/test/src/math/smoke/CMakeLists.txt   | 15 +++++++++++++++
 libc/test/src/math/smoke/f16addl_test.cpp | 13 +++++++++++++
 11 files changed, 111 insertions(+), 2 deletions(-)
 create mode 100644 libc/src/math/f16addl.h
 create mode 100644 libc/src/math/generic/f16addl.cpp
 create mode 100644 libc/test/src/math/f16addl_test.cpp
 create mode 100644 libc/test/src/math/smoke/f16addl_test.cpp

diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 8b4018116d9e0..685586c6ea94a 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -539,6 +539,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.copysignf16
     libc.src.math.f16add
     libc.src.math.f16addf
+    libc.src.math.f16addl
     libc.src.math.f16div
     libc.src.math.f16divf
     libc.src.math.f16divl
@@ -600,8 +601,8 @@ if(LIBC_TYPES_HAS_FLOAT16)
     list(APPEND TARGET_LIBM_ENTRYPOINTS
       # math.h C23 mixed _Float16 and _Float128 entrypoints
       libc.src.math.f16addf128
-      libc.src.math.f16fmaf128
       libc.src.math.f16divf128
+      libc.src.math.f16fmaf128
     )
   endif()
 endif()
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 572a4f0ec0bb8..3c9515199c60d 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -124,7 +124,7 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | dsub             | N/A              | N/A             |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16add           | |check|\*        | |check|         |                        | N/A                  | |check|                | 7.12.14.1              | F.10.11                    |
+| f16add           | |check|\*        | |check|         | |check|                | N/A                  | |check|                | 7.12.14.1              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16div           | |check|\*        | |check|\*       | |check|\*              | N/A                  | |check|                | 7.12.14.4              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 0a03d83c85644..5d25ad07beb39 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -730,6 +730,7 @@ def StdC : StandardSpec<"stdc"> {
           GuardedFunctionSpec<"setpayloadsigf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
           GuardedFunctionSpec<"f16add", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
+          GuardedFunctionSpec<"f16addl", RetValSpec<Float16Type>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16addf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 84deaf7de4cd6..23d33e164fdda 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -101,6 +101,7 @@ add_math_entrypoint_object(expm1f)
 
 add_math_entrypoint_object(f16add)
 add_math_entrypoint_object(f16addf)
+add_math_entrypoint_object(f16addl)
 add_math_entrypoint_object(f16addf128)
 
 add_math_entrypoint_object(f16div)
diff --git a/libc/src/math/f16addl.h b/libc/src/math/f16addl.h
new file mode 100644
index 0000000000000..6a7267a10d0c6
--- /dev/null
+++ b/libc/src/math/f16addl.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for f16addl -----------------------*- 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_F16ADDL_H
+#define LLVM_LIBC_SRC_MATH_F16ADDL_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 f16addl(long double x, long double y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_F16ADDL_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index a0b1a88ceab1a..b62f7954951c9 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3802,6 +3802,19 @@ add_entrypoint_object(
     -O3
 )
 
+add_entrypoint_object(
+  f16addl
+  SRCS
+    f16addl.cpp
+  HDRS
+    ../f16addl.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.generic.add_sub
+  COMPILE_OPTIONS
+    -O3
+)
+
 add_entrypoint_object(
   f16addf128
   SRCS
diff --git a/libc/src/math/generic/f16addl.cpp b/libc/src/math/generic/f16addl.cpp
new file mode 100644
index 0000000000000..d32d09d0dbb83
--- /dev/null
+++ b/libc/src/math/generic/f16addl.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of f16addl 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/f16addl.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, f16addl, (long double x, long double y)) {
+  return fputil::generic::add<float16>(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 9abe3f48ea0f7..e58c215fb2dd1 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1928,6 +1928,19 @@ add_fp_unittest(
     libc.src.math.f16addf
 )
 
+add_fp_unittest(
+  f16addl_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    f16addl_test.cpp
+  HDRS
+    AddTest.h
+  DEPENDS
+    libc.src.math.f16addl
+)
+
 add_fp_unittest(
   f16subf_test
   NEED_MPFR
diff --git a/libc/test/src/math/f16addl_test.cpp b/libc/test/src/math/f16addl_test.cpp
new file mode 100644
index 0000000000000..f8e0d9ba6b4de
--- /dev/null
+++ b/libc/test/src/math/f16addl_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16addl ---------------------------------------------===//
+//
+// 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 "AddTest.h"
+
+#include "src/math/f16addl.h"
+
+LIST_ADD_TESTS(float16, long double, LIBC_NAMESPACE::f16addl)
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 3b00abb2363f3..920f0ec21781e 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3660,6 +3660,21 @@ add_fp_unittest(
     libc.src.math.f16addf
 )
 
+add_fp_unittest(
+  f16addl_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    f16addl_test.cpp
+  HDRS
+    AddTest.h
+  DEPENDS
+    libc.hdr.errno_macros
+    libc.hdr.fenv_macros
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.math.f16addl
+)
+
 add_fp_unittest(
   f16addf128_test
   SUITE
diff --git a/libc/test/src/math/smoke/f16addl_test.cpp b/libc/test/src/math/smoke/f16addl_test.cpp
new file mode 100644
index 0000000000000..f8e0d9ba6b4de
--- /dev/null
+++ b/libc/test/src/math/smoke/f16addl_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16addl ---------------------------------------------===//
+//
+// 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 "AddTest.h"
+
+#include "src/math/f16addl.h"
+
+LIST_ADD_TESTS(float16, long double, LIBC_NAMESPACE::f16addl)

>From 43fd804010348f04cee2a2a2db92f51c88413829 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Fri, 28 Jun 2024 17:20:44 +0200
Subject: [PATCH 09/12] [libc][math][c23] Add f16sub C23 math function

---
 libc/config/linux/aarch64/entrypoints.txt |  1 +
 libc/config/linux/x86_64/entrypoints.txt  |  1 +
 libc/docs/math/index.rst                  |  2 +-
 libc/spec/stdc.td                         |  2 ++
 libc/src/math/CMakeLists.txt              |  1 +
 libc/src/math/f16sub.h                    | 20 ++++++++++++++++++++
 libc/src/math/generic/CMakeLists.txt      | 13 +++++++++++++
 libc/src/math/generic/f16sub.cpp          | 19 +++++++++++++++++++
 libc/test/src/math/CMakeLists.txt         | 13 +++++++++++++
 libc/test/src/math/f16sub_test.cpp        | 13 +++++++++++++
 libc/test/src/math/smoke/CMakeLists.txt   | 14 ++++++++++++++
 libc/test/src/math/smoke/f16sub_test.cpp  | 13 +++++++++++++
 12 files changed, 111 insertions(+), 1 deletion(-)
 create mode 100644 libc/src/math/f16sub.h
 create mode 100644 libc/src/math/generic/f16sub.cpp
 create mode 100644 libc/test/src/math/f16sub_test.cpp
 create mode 100644 libc/test/src/math/smoke/f16sub_test.cpp

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index ac3c5e2cbdcc4..456c5ce81f805 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -513,6 +513,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.f16divf
     libc.src.math.f16fmaf
     libc.src.math.f16sqrtf
+    libc.src.math.f16sub
     libc.src.math.f16subf
     libc.src.math.fabsf16
     libc.src.math.fdimf16
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 685586c6ea94a..ace97d5586384 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -547,6 +547,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.f16fmaf
     libc.src.math.f16fmal
     libc.src.math.f16sqrtf
+    libc.src.math.f16sub
     libc.src.math.f16subf
     libc.src.math.fabsf16
     libc.src.math.fdimf16
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 3c9515199c60d..4726cb9c13df6 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -130,7 +130,7 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16fma           | |check|          | |check|         | |check|                | N/A                  | |check|                | 7.12.14.5              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16sub           | |check|\*        |                 |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
+| f16sub           | |check|\*        | |check|         |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | fabs             | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.7.3               | F.10.4.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 5d25ad07beb39..07ba01f5f497f 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -733,6 +733,8 @@ def StdC : StandardSpec<"stdc"> {
           GuardedFunctionSpec<"f16addl", RetValSpec<Float16Type>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16addf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
+          GuardedFunctionSpec<"f16sub", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
+
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16sqrtf", RetValSpec<Float16Type>, [ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 23d33e164fdda..82ec115491cd2 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -116,6 +116,7 @@ add_math_entrypoint_object(f16fmaf128)
 
 add_math_entrypoint_object(f16sqrtf)
 
+add_math_entrypoint_object(f16sub)
 add_math_entrypoint_object(f16subf)
 
 add_math_entrypoint_object(fabs)
diff --git a/libc/src/math/f16sub.h b/libc/src/math/f16sub.h
new file mode 100644
index 0000000000000..66f82daada019
--- /dev/null
+++ b/libc/src/math/f16sub.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for f16sub ------------------------*- 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_F16SUB_H
+#define LLVM_LIBC_SRC_MATH_F16SUB_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 f16sub(double x, double y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_F16SUB_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index b62f7954951c9..636c545180b83 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3828,6 +3828,19 @@ add_entrypoint_object(
     -O3
 )
 
+add_entrypoint_object(
+  f16sub
+  SRCS
+    f16sub.cpp
+  HDRS
+    ../f16sub.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.generic.add_sub
+  COMPILE_OPTIONS
+    -O3
+)
+
 add_entrypoint_object(
   f16subf
   SRCS
diff --git a/libc/src/math/generic/f16sub.cpp b/libc/src/math/generic/f16sub.cpp
new file mode 100644
index 0000000000000..114c8ad3155e1
--- /dev/null
+++ b/libc/src/math/generic/f16sub.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of f16sub 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/f16sub.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, f16sub, (double x, double y)) {
+  return fputil::generic::sub<float16>(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index e58c215fb2dd1..e96d96edd553b 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1941,6 +1941,19 @@ add_fp_unittest(
     libc.src.math.f16addl
 )
 
+add_fp_unittest(
+  f16sub_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    f16sub_test.cpp
+  HDRS
+    SubTest.h
+  DEPENDS
+    libc.src.math.f16sub
+)
+
 add_fp_unittest(
   f16subf_test
   NEED_MPFR
diff --git a/libc/test/src/math/f16sub_test.cpp b/libc/test/src/math/f16sub_test.cpp
new file mode 100644
index 0000000000000..37b970952fe5e
--- /dev/null
+++ b/libc/test/src/math/f16sub_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16sub ----------------------------------------------===/
+//
+// 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 "SubTest.h"
+
+#include "src/math/f16sub.h"
+
+LIST_SUB_TESTS(float16, double, LIBC_NAMESPACE::f16sub)
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 920f0ec21781e..d4c04a3e0b164 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3690,6 +3690,20 @@ add_fp_unittest(
     libc.src.math.f16addf128
 )
 
+add_fp_unittest(
+  f16sub_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    f16sub_test.cpp
+  HDRS
+    SubTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.math.f16sub
+)
+
 add_fp_unittest(
   f16subf_test
   SUITE
diff --git a/libc/test/src/math/smoke/f16sub_test.cpp b/libc/test/src/math/smoke/f16sub_test.cpp
new file mode 100644
index 0000000000000..4ab347ba614fb
--- /dev/null
+++ b/libc/test/src/math/smoke/f16sub_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16sub ----------------------------------------------===//
+//
+// 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 "SubTest.h"
+
+#include "src/math/f16sub.h"
+
+LIST_SUB_TESTS(float16, double, LIBC_NAMESPACE::f16sub)

>From 0ba200087717a8949b1eda33e8016332ceb65770 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Fri, 28 Jun 2024 17:23:54 +0200
Subject: [PATCH 10/12] [libc][math][c23] Add f16subf128 C23 math function

---
 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/f16subf128.h                   | 20 ++++++++++++++++++++
 libc/src/math/generic/CMakeLists.txt         | 13 +++++++++++++
 libc/src/math/generic/f16subf128.cpp         | 19 +++++++++++++++++++
 libc/test/src/math/smoke/CMakeLists.txt      | 14 ++++++++++++++
 libc/test/src/math/smoke/f16subf128_test.cpp | 13 +++++++++++++
 9 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 libc/src/math/f16subf128.h
 create mode 100644 libc/src/math/generic/f16subf128.cpp
 create mode 100644 libc/test/src/math/smoke/f16subf128_test.cpp

diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index ace97d5586384..6ca11ee1ddf54 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -604,6 +604,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
       libc.src.math.f16addf128
       libc.src.math.f16divf128
       libc.src.math.f16fmaf128
+      libc.src.math.f16subf128
     )
   endif()
 endif()
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 4726cb9c13df6..9ba52cc37e92a 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -130,7 +130,7 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16fma           | |check|          | |check|         | |check|                | N/A                  | |check|                | 7.12.14.5              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16sub           | |check|\*        | |check|         |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
+| f16sub           | |check|\*        | |check|         |                        | N/A                  | |check|                | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | fabs             | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.7.3               | F.10.4.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 07ba01f5f497f..afd977d11483e 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -734,6 +734,7 @@ def StdC : StandardSpec<"stdc"> {
           GuardedFunctionSpec<"f16addf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16sub", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
+          GuardedFunctionSpec<"f16subf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 82ec115491cd2..467855ac8e10f 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -118,6 +118,7 @@ add_math_entrypoint_object(f16sqrtf)
 
 add_math_entrypoint_object(f16sub)
 add_math_entrypoint_object(f16subf)
+add_math_entrypoint_object(f16subf128)
 
 add_math_entrypoint_object(fabs)
 add_math_entrypoint_object(fabsf)
diff --git a/libc/src/math/f16subf128.h b/libc/src/math/f16subf128.h
new file mode 100644
index 0000000000000..eb674297ba266
--- /dev/null
+++ b/libc/src/math/f16subf128.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for f16subf128 --------------------*- 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_F16SUBF128_H
+#define LLVM_LIBC_SRC_MATH_F16SUBF128_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 f16subf128(float128 x, float128 y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_F16SUBF128_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 636c545180b83..5ca8f81e712fe 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3854,6 +3854,19 @@ add_entrypoint_object(
     -O3
 )
 
+add_entrypoint_object(
+  f16subf128
+  SRCS
+    f16subf128.cpp
+  HDRS
+    ../f16subf128.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.generic.add_sub
+  COMPILE_OPTIONS
+    -O3
+)
+
 add_entrypoint_object(
   f16div
   SRCS
diff --git a/libc/src/math/generic/f16subf128.cpp b/libc/src/math/generic/f16subf128.cpp
new file mode 100644
index 0000000000000..1f9ff28abdf29
--- /dev/null
+++ b/libc/src/math/generic/f16subf128.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of f16subf128 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/f16subf128.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, f16subf128, (float128 x, float128 y)) {
+  return fputil::generic::sub<float16>(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index d4c04a3e0b164..81b7d1ff5491f 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3718,6 +3718,20 @@ add_fp_unittest(
     libc.src.math.f16subf
 )
 
+add_fp_unittest(
+  f16subf128_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    f16subf128_test.cpp
+  HDRS
+    SubTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.math.f16subf128
+)
+
 add_fp_unittest(
   f16div_test
   SUITE
diff --git a/libc/test/src/math/smoke/f16subf128_test.cpp b/libc/test/src/math/smoke/f16subf128_test.cpp
new file mode 100644
index 0000000000000..4936d89c1f904
--- /dev/null
+++ b/libc/test/src/math/smoke/f16subf128_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16subf128 ------------------------------------------===//
+//
+// 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 "SubTest.h"
+
+#include "src/math/f16subf128.h"
+
+LIST_SUB_TESTS(float16, float128, LIBC_NAMESPACE::f16subf128)

>From 42dd50a15a35323d0d2b85ce5a80df35a255463e Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Fri, 28 Jun 2024 17:28:07 +0200
Subject: [PATCH 11/12] [libc][math][c23] Add f16subl C23 math function

---
 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/f16subl.h                   | 20 ++++++++++++++++++++
 libc/src/math/generic/CMakeLists.txt      | 13 +++++++++++++
 libc/src/math/generic/f16subl.cpp         | 19 +++++++++++++++++++
 libc/test/src/math/CMakeLists.txt         | 13 +++++++++++++
 libc/test/src/math/f16subl_test.cpp       | 13 +++++++++++++
 libc/test/src/math/smoke/CMakeLists.txt   | 14 ++++++++++++++
 libc/test/src/math/smoke/f16subl_test.cpp | 13 +++++++++++++
 11 files changed, 109 insertions(+), 1 deletion(-)
 create mode 100644 libc/src/math/f16subl.h
 create mode 100644 libc/src/math/generic/f16subl.cpp
 create mode 100644 libc/test/src/math/f16subl_test.cpp
 create mode 100644 libc/test/src/math/smoke/f16subl_test.cpp

diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 6ca11ee1ddf54..b5f5afcdd4f3b 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -549,6 +549,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.f16sqrtf
     libc.src.math.f16sub
     libc.src.math.f16subf
+    libc.src.math.f16subl
     libc.src.math.fabsf16
     libc.src.math.fdimf16
     libc.src.math.floorf16
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 9ba52cc37e92a..3c0cb08811c9c 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -130,7 +130,7 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16fma           | |check|          | |check|         | |check|                | N/A                  | |check|                | 7.12.14.5              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16sub           | |check|\*        | |check|         |                        | N/A                  | |check|                | 7.12.14.2              | F.10.11                    |
+| f16sub           | |check|\*        | |check|         | |check|                | N/A                  | |check|                | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | fabs             | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.7.3               | F.10.4.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index afd977d11483e..8b4327ae4b891 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -734,6 +734,7 @@ def StdC : StandardSpec<"stdc"> {
           GuardedFunctionSpec<"f16addf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16sub", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
+          GuardedFunctionSpec<"f16subl", RetValSpec<Float16Type>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16subf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 467855ac8e10f..34630d73f2b85 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -118,6 +118,7 @@ add_math_entrypoint_object(f16sqrtf)
 
 add_math_entrypoint_object(f16sub)
 add_math_entrypoint_object(f16subf)
+add_math_entrypoint_object(f16subl)
 add_math_entrypoint_object(f16subf128)
 
 add_math_entrypoint_object(fabs)
diff --git a/libc/src/math/f16subl.h b/libc/src/math/f16subl.h
new file mode 100644
index 0000000000000..43b44a57a604e
--- /dev/null
+++ b/libc/src/math/f16subl.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for f16subl -----------------------*- 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_F16SUBL_H
+#define LLVM_LIBC_SRC_MATH_F16SUBL_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 f16subl(long double x, long double y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_F16SUBL_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 5ca8f81e712fe..06fb6b2cdaab7 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3854,6 +3854,19 @@ add_entrypoint_object(
     -O3
 )
 
+add_entrypoint_object(
+  f16subl
+  SRCS
+    f16subl.cpp
+  HDRS
+    ../f16subl.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.generic.add_sub
+  COMPILE_OPTIONS
+    -O3
+)
+
 add_entrypoint_object(
   f16subf128
   SRCS
diff --git a/libc/src/math/generic/f16subl.cpp b/libc/src/math/generic/f16subl.cpp
new file mode 100644
index 0000000000000..31970af9a2366
--- /dev/null
+++ b/libc/src/math/generic/f16subl.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of f16subl 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/f16subl.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, f16subl, (long double x, long double y)) {
+  return fputil::generic::sub<float16>(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index e96d96edd553b..26b9822102c2c 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1967,6 +1967,19 @@ add_fp_unittest(
     libc.src.math.f16subf
 )
 
+add_fp_unittest(
+  f16subl_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    f16subl_test.cpp
+  HDRS
+    SubTest.h
+  DEPENDS
+    libc.src.math.f16subl
+)
+
 add_fp_unittest(
   f16div_test
   NEED_MPFR
diff --git a/libc/test/src/math/f16subl_test.cpp b/libc/test/src/math/f16subl_test.cpp
new file mode 100644
index 0000000000000..c41e6e97bab09
--- /dev/null
+++ b/libc/test/src/math/f16subl_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16subl ---------------------------------------------===//
+//
+// 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 "SubTest.h"
+
+#include "src/math/f16subl.h"
+
+LIST_SUB_TESTS(float16, long double, LIBC_NAMESPACE::f16subl)
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 81b7d1ff5491f..8f1375bed5ed2 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3718,6 +3718,20 @@ add_fp_unittest(
     libc.src.math.f16subf
 )
 
+add_fp_unittest(
+  f16subl_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    f16subl_test.cpp
+  HDRS
+    SubTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.__support.FPUtil.basic_operations
+    libc.src.math.f16subl
+)
+
 add_fp_unittest(
   f16subf128_test
   SUITE
diff --git a/libc/test/src/math/smoke/f16subl_test.cpp b/libc/test/src/math/smoke/f16subl_test.cpp
new file mode 100644
index 0000000000000..c41e6e97bab09
--- /dev/null
+++ b/libc/test/src/math/smoke/f16subl_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for f16subl ---------------------------------------------===//
+//
+// 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 "SubTest.h"
+
+#include "src/math/f16subl.h"
+
+LIST_SUB_TESTS(float16, long double, LIBC_NAMESPACE::f16subl)

>From 83d4b9026e42ba01ceb3a9eb7c61d95393b1dd61 Mon Sep 17 00:00:00 2001
From: OverMighty <its.overmighty at gmail.com>
Date: Sun, 30 Jun 2024 01:43:58 +0200
Subject: [PATCH 12/12] [libc][math][c23] Move f16{add,sub}{,l} specs to
 llvm_libc_ext.td

---
 libc/docs/math/index.rst   | 4 ++--
 libc/spec/llvm_libc_ext.td | 4 ++++
 libc/spec/stdc.td          | 4 ----
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index 3c0cb08811c9c..392bedae4110b 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -124,13 +124,13 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | dsub             | N/A              | N/A             |                        | N/A                  |                        | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16add           | |check|\*        | |check|         | |check|                | N/A                  | |check|                | 7.12.14.1              | F.10.11                    |
+| f16add           | |check|\*        | |check|\*       | |check|\*              | N/A                  | |check|                | 7.12.14.1              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16div           | |check|\*        | |check|\*       | |check|\*              | N/A                  | |check|                | 7.12.14.4              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | f16fma           | |check|          | |check|         | |check|                | N/A                  | |check|                | 7.12.14.5              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| f16sub           | |check|\*        | |check|         | |check|                | N/A                  | |check|                | 7.12.14.2              | F.10.11                    |
+| f16sub           | |check|\*        | |check|\*       | |check|\*              | N/A                  | |check|                | 7.12.14.2              | F.10.11                    |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | fabs             | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.7.3               | F.10.4.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/llvm_libc_ext.td b/libc/spec/llvm_libc_ext.td
index 24dfca9befe36..a5fec94f03966 100644
--- a/libc/spec/llvm_libc_ext.td
+++ b/libc/spec/llvm_libc_ext.td
@@ -57,8 +57,12 @@ def LLVMLibcExt : StandardSpec<"llvm_libc_ext"> {
       [], // Types
       [], // Enumerations
       [
+          GuardedFunctionSpec<"f16add", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
+          GuardedFunctionSpec<"f16addl", RetValSpec<Float16Type>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16addf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
 
+          GuardedFunctionSpec<"f16sub", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
+          GuardedFunctionSpec<"f16subl", RetValSpec<Float16Type>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16subf", RetValSpec<Float16Type>, [ArgSpec<FloatType>, ArgSpec<FloatType>], "LIBC_TYPES_HAS_FLOAT16">,
 
           GuardedFunctionSpec<"f16div", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 8b4327ae4b891..43bac3c80d113 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -729,12 +729,8 @@ def StdC : StandardSpec<"stdc"> {
 
           GuardedFunctionSpec<"setpayloadsigf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
-          GuardedFunctionSpec<"f16add", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
-          GuardedFunctionSpec<"f16addl", RetValSpec<Float16Type>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16addf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
-          GuardedFunctionSpec<"f16sub", RetValSpec<Float16Type>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
-          GuardedFunctionSpec<"f16subl", RetValSpec<Float16Type>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"f16subf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,



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