[libc][math][c23] Add {nextafter,nexttoward,nextup,nextdown}f16 C23 math functions (#94535)

#93566

22 files changed, 371 insertions, 32 deletions

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 2a4f789..a8cb468 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -514,6 +514,10 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.lrintf16
     libc.src.math.lroundf16
     libc.src.math.nearbyintf16
+    libc.src.math.nextafterf16
+    libc.src.math.nextdownf16
+    libc.src.math.nexttowardf16
+    libc.src.math.nextupf16
     libc.src.math.rintf16
     libc.src.math.roundf16
     libc.src.math.roundevenf16
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index fe12182..9db044e 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -547,6 +547,10 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.lrintf16
     libc.src.math.lroundf16
     libc.src.math.nearbyintf16
+    libc.src.math.nextafterf16
+    libc.src.math.nextdownf16
+    libc.src.math.nexttowardf16
+    libc.src.math.nextupf16
     libc.src.math.rintf16
     libc.src.math.roundf16
     libc.src.math.roundevenf16
diff --git a/libc/docs/c23.rst b/libc/docs/c23.rst
index 5bbb056..fa7a598 100644
--- a/libc/docs/c23.rst
+++ b/libc/docs/c23.rst
@@ -59,8 +59,8 @@ Additions:
   * ufromfp* |check|
   * fromfpx* |check|
   * ufromfpx* |check|
-  * nextup*
-  * nextdown*
+  * nextup* |check|
+  * nextdown* |check|
   * canonicalize* |check|
   * fmaximum*
   * fminimum*
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
index afadf71..8c3c07a 100644
--- a/libc/docs/math/index.rst
+++ b/libc/docs/math/index.rst
@@ -190,13 +190,13 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | nearbyint        | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.9.3               | F.10.6.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| nextafter        | |check|          | |check|         | |check|                |                      | |check|                | 7.12.11.3              | F.10.8.3                   |
+| nextafter        | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.11.3              | F.10.8.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| nextdown         | |check|          | |check|         | |check|                |                      | |check|                | 7.12.11.6              | F.10.8.6                   |
+| nextdown         | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.11.6              | F.10.8.6                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| nexttoward       | |check|          | |check|         | |check|                |                      | N/A                    | 7.12.11.4              | F.10.8.4                   |
+| nexttoward       | |check|          | |check|         | |check|                | |check|              | N/A                    | 7.12.11.4              | F.10.8.4                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| nextup           | |check|          | |check|         | |check|                |                      | |check|                | 7.12.11.5              | F.10.8.5                   |
+| nextup           | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.11.5              | F.10.8.5                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | remainder        | |check|          | |check|         | |check|                |                      |                        | 7.12.10.2              | F.10.7.2                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 3098736..f867a3d 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -634,20 +634,24 @@ def StdC : StandardSpec<"stdc"> {
           FunctionSpec<"nextafterf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<FloatType>]>,
           FunctionSpec<"nextafter", RetValSpec<DoubleType>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>]>,
           FunctionSpec<"nextafterl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>]>,
+          GuardedFunctionSpec<"nextafterf16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"nextafterf128", RetValSpec<Float128Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT128">,
 
           FunctionSpec<"nexttowardf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<LongDoubleType>]>,
           FunctionSpec<"nexttoward", RetValSpec<DoubleType>, [ArgSpec<DoubleType>, ArgSpec<LongDoubleType>]>,
           FunctionSpec<"nexttowardl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>]>,
+          GuardedFunctionSpec<"nexttowardf16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
           FunctionSpec<"nextdown", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
           FunctionSpec<"nextdownf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
           FunctionSpec<"nextdownl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>]>,
+          GuardedFunctionSpec<"nextdownf16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"nextdownf128", RetValSpec<Float128Type>, [ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT128">,
 
           FunctionSpec<"nextup", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
           FunctionSpec<"nextupf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
           FunctionSpec<"nextupl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>]>,
+          GuardedFunctionSpec<"nextupf16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
           GuardedFunctionSpec<"nextupf128", RetValSpec<Float128Type>, [ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT128">,
 
           FunctionSpec<"powf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<FloatType>]>,
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 83ce322..4984666 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -272,20 +272,24 @@ add_math_entrypoint_object(nearbyintf128)
 add_math_entrypoint_object(nextafter)
 add_math_entrypoint_object(nextafterf)
 add_math_entrypoint_object(nextafterl)
+add_math_entrypoint_object(nextafterf16)
 add_math_entrypoint_object(nextafterf128)
 
 add_math_entrypoint_object(nexttoward)
 add_math_entrypoint_object(nexttowardf)
 add_math_entrypoint_object(nexttowardl)
+add_math_entrypoint_object(nexttowardf16)
 
 add_math_entrypoint_object(nextdown)
 add_math_entrypoint_object(nextdownf)
 add_math_entrypoint_object(nextdownl)
+add_math_entrypoint_object(nextdownf16)
 add_math_entrypoint_object(nextdownf128)
 
 add_math_entrypoint_object(nextup)
 add_math_entrypoint_object(nextupf)
 add_math_entrypoint_object(nextupl)
+add_math_entrypoint_object(nextupf16)
 add_math_entrypoint_object(nextupf128)
 
 add_math_entrypoint_object(pow)
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 00e2f0a..c183f09 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -2551,6 +2551,19 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  nextafterf16
+  SRCS
+    nextafterf16.cpp
+  HDRS
+    ../nextafterf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.manipulation_functions
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
   nextafterf128
   SRCS
     nextafterf128.cpp
@@ -2600,6 +2613,19 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  nexttowardf16
+  SRCS
+    nexttowardf16.cpp
+  HDRS
+    ../nexttowardf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.manipulation_functions
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
   nextdown
   SRCS
     nextdown.cpp
@@ -2636,6 +2662,19 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  nextdownf16
+  SRCS
+    nextdownf16.cpp
+  HDRS
+    ../nextdownf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.manipulation_functions
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
   nextdownf128
   SRCS
     nextdownf128.cpp
@@ -2685,6 +2724,19 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  nextupf16
+  SRCS
+    nextupf16.cpp
+  HDRS
+    ../nextupf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.manipulation_functions
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
   nextupf128
   SRCS
     nextupf128.cpp
diff --git a/libc/src/math/generic/nextafterf16.cpp b/libc/src/math/generic/nextafterf16.cpp
new file mode 100644
index 0000000..144b3fc
--- /dev/null
+++ b/libc/src/math/generic/nextafterf16.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of nextafterf16 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/nextafterf16.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, nextafterf16, (float16 x, float16 y)) {
+  return fputil::nextafter(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/generic/nextdownf16.cpp b/libc/src/math/generic/nextdownf16.cpp
new file mode 100644
index 0000000..9fdaa9d
--- /dev/null
+++ b/libc/src/math/generic/nextdownf16.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of nextdownf16 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/nextdownf16.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, nextdownf16, (float16 x)) {
+  return fputil::nextupdown</*IsDown=*/true>(x);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/generic/nexttowardf16.cpp b/libc/src/math/generic/nexttowardf16.cpp
new file mode 100644
index 0000000..d1d78e8
--- /dev/null
+++ b/libc/src/math/generic/nexttowardf16.cpp
@@ -0,0 +1,21 @@
+//===-- Implementation of nexttowardf16 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/nexttowardf16.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, nexttowardf16, (float16 x, long double y)) {
+  // We can reuse the nextafter implementation because the internal nextafter is
+  // templated on the types of the arguments.
+  return fputil::nextafter(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/generic/nextupf16.cpp b/libc/src/math/generic/nextupf16.cpp
new file mode 100644
index 0000000..5d3d52c
--- /dev/null
+++ b/libc/src/math/generic/nextupf16.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of nextupf16 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/nextupf16.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, nextupf16, (float16 x)) {
+  return fputil::nextupdown</*IsDown=*/false>(x);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/nextafterf16.h b/libc/src/math/nextafterf16.h
new file mode 100644
index 0000000..293569e
--- /dev/null
+++ b/libc/src/math/nextafterf16.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for nextafterf16 ------------------*- 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_NEXTAFTERF16_H
+#define LLVM_LIBC_SRC_MATH_NEXTAFTERF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 nextafterf16(float16 x, float16 y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_NEXTAFTERF16_H
diff --git a/libc/src/math/nextdownf16.h b/libc/src/math/nextdownf16.h
new file mode 100644
index 0000000..1913757
--- /dev/null
+++ b/libc/src/math/nextdownf16.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for nextdownf16 -------------------*- 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_NEXTDOWNF16_H
+#define LLVM_LIBC_SRC_MATH_NEXTDOWNF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 nextdownf16(float16 x);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_NEXTDOWNF16_H
diff --git a/libc/src/math/nexttowardf16.h b/libc/src/math/nexttowardf16.h
new file mode 100644
index 0000000..604eb32
--- /dev/null
+++ b/libc/src/math/nexttowardf16.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for nexttowardf16 -----------------*- 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_NEXTTOWARDF16_H
+#define LLVM_LIBC_SRC_MATH_NEXTTOWARDF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 nexttowardf16(float16 x, long double y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_NEXTTOWARDF16_H
diff --git a/libc/src/math/nextupf16.h b/libc/src/math/nextupf16.h
new file mode 100644
index 0000000..b2973e4
--- /dev/null
+++ b/libc/src/math/nextupf16.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for nextupf16 ---------------------*- 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_NEXTUPF16_H
+#define LLVM_LIBC_SRC_MATH_NEXTUPF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 nextupf16(float16 x);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_NEXTUPF16_H
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index a331c02..8919b54 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -2541,8 +2541,10 @@ add_fp_unittest(
   HDRS
     NextAfterTest.h
   DEPENDS
+    libc.hdr.fenv_macros
     libc.src.math.nextafter
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.bit
+    libc.src.__support.FPUtil.fenv_impl
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -2555,8 +2557,10 @@ add_fp_unittest(
   HDRS
     NextAfterTest.h
   DEPENDS
+    libc.hdr.fenv_macros
     libc.src.math.nextafterf
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.bit
+    libc.src.__support.FPUtil.fenv_impl
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -2569,8 +2573,26 @@ add_fp_unittest(
   HDRS
     NextAfterTest.h
   DEPENDS
+    libc.hdr.fenv_macros
     libc.src.math.nextafterl
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.bit
+    libc.src.__support.FPUtil.fenv_impl
+    libc.src.__support.FPUtil.fp_bits
+)
+
+add_fp_unittest(
+  nextafterf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    nextafterf16_test.cpp
+  HDRS
+    NextAfterTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.math.nextafterf16
+    libc.src.__support.CPP.bit
+    libc.src.__support.FPUtil.fenv_impl
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -2583,8 +2605,10 @@ add_fp_unittest(
   HDRS
     NextAfterTest.h
   DEPENDS
+    libc.hdr.fenv_macros
     libc.src.math.nextafterf128
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.bit
+    libc.src.__support.FPUtil.fenv_impl
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -2599,8 +2623,10 @@ if(NOT LIBC_TARGET_OS_IS_GPU)
     HDRS
       NextTowardTest.h
     DEPENDS
+      libc.hdr.fenv_macros
       libc.src.math.nexttoward
-      libc.src.__support.FPUtil.basic_operations
+      libc.src.__support.CPP.bit
+      libc.src.__support.FPUtil.fenv_impl
       libc.src.__support.FPUtil.fp_bits
   )
 
@@ -2613,8 +2639,10 @@ if(NOT LIBC_TARGET_OS_IS_GPU)
     HDRS
       NextTowardTest.h
     DEPENDS
+      libc.hdr.fenv_macros
       libc.src.math.nexttowardf
-      libc.src.__support.FPUtil.basic_operations
+      libc.src.__support.CPP.bit
+      libc.src.__support.FPUtil.fenv_impl
       libc.src.__support.FPUtil.fp_bits
   )
 endif()
@@ -2628,8 +2656,26 @@ add_fp_unittest(
   HDRS
     NextTowardTest.h
   DEPENDS
+    libc.hdr.fenv_macros
     libc.src.math.nexttowardl
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.bit
+    libc.src.__support.FPUtil.fenv_impl
+    libc.src.__support.FPUtil.fp_bits
+)
+
+add_fp_unittest(
+  nexttowardf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    nexttowardf16_test.cpp
+  HDRS
+    NextTowardTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.math.nexttowardf16
+    libc.src.__support.CPP.bit
+    libc.src.__support.FPUtil.fenv_impl
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -2643,7 +2689,6 @@ add_fp_unittest(
     NextDownTest.h
   DEPENDS
     libc.src.math.nextdown
-    libc.src.__support.FPUtil.manipulation_functions
 )
 
 add_fp_unittest(
@@ -2656,7 +2701,6 @@ add_fp_unittest(
     NextDownTest.h
   DEPENDS
     libc.src.math.nextdownf
-    libc.src.__support.FPUtil.manipulation_functions
 )
 
 add_fp_unittest(
@@ -2669,7 +2713,18 @@ add_fp_unittest(
     NextDownTest.h
   DEPENDS
     libc.src.math.nextdownl
-    libc.src.__support.FPUtil.manipulation_functions
+)
+
+add_fp_unittest(
+  nextdownf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    nextdownf16_test.cpp
+  HDRS
+    NextDownTest.h
+  DEPENDS
+    libc.src.math.nextdownf16
 )
 
 add_fp_unittest(
@@ -2682,7 +2737,6 @@ add_fp_unittest(
     NextDownTest.h
   DEPENDS
     libc.src.math.nextdownf128
-    libc.src.__support.FPUtil.manipulation_functions
 )
 
 add_fp_unittest(
@@ -2695,7 +2749,6 @@ add_fp_unittest(
     NextUpTest.h
   DEPENDS
     libc.src.math.nextup
-    libc.src.__support.FPUtil.manipulation_functions
 )
 
 add_fp_unittest(
@@ -2708,7 +2761,6 @@ add_fp_unittest(
     NextUpTest.h
   DEPENDS
     libc.src.math.nextupf
-    libc.src.__support.FPUtil.manipulation_functions
 )
 
 add_fp_unittest(
@@ -2721,7 +2773,18 @@ add_fp_unittest(
     NextUpTest.h
   DEPENDS
     libc.src.math.nextupl
-    libc.src.__support.FPUtil.manipulation_functions
+)
+
+add_fp_unittest(
+  nextupf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    nextupf16_test.cpp
+  HDRS
+    NextUpTest.h
+  DEPENDS
+    libc.src.math.nextupf16
 )
 
 add_fp_unittest(
@@ -2734,7 +2797,6 @@ add_fp_unittest(
     NextUpTest.h
   DEPENDS
     libc.src.math.nextupf128
-    libc.src.__support.FPUtil.manipulation_functions
 )
 
 # TODO(lntue): The current implementation of fputil::general::fma<float> is only
diff --git a/libc/test/src/math/smoke/NextAfterTest.h b/libc/test/src/math/smoke/NextAfterTest.h
index d65ccdf..6278f89 100644
--- a/libc/test/src/math/smoke/NextAfterTest.h
+++ b/libc/test/src/math/smoke/NextAfterTest.h
@@ -9,15 +9,15 @@
 #ifndef LLVM_LIBC_TEST_SRC_MATH_NEXTAFTERTEST_H
 #define LLVM_LIBC_TEST_SRC_MATH_NEXTAFTERTEST_H
 
-#include "hdr/math_macros.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 "test/UnitTest/FEnvSafeTest.h"
 #include "test/UnitTest/FPMatcher.h"
 #include "test/UnitTest/Test.h"
 
+#include "hdr/fenv_macros.h"
+
 // TODO: Strengthen errno,exception checks and remove these assert macros
 // after new matchers/test fixtures are added
 #define ASSERT_FP_EQ_WITH_EXCEPTION(result, expected, expected_exception)      \
@@ -181,7 +181,7 @@ public:
     result_bits = FPBits(result);
     ASSERT_EQ(result_bits.get_biased_exponent(), x_bits.get_biased_exponent());
     ASSERT_EQ(result_bits.get_mantissa(),
-              x_bits.get_mantissa() + StorageType(1));
+              static_cast<StorageType>(x_bits.get_mantissa() + StorageType(1)));
 
     x = -x;
 
@@ -195,7 +195,7 @@ public:
     result_bits = FPBits(result);
     ASSERT_EQ(result_bits.get_biased_exponent(), x_bits.get_biased_exponent());
     ASSERT_EQ(result_bits.get_mantissa(),
-              x_bits.get_mantissa() + StorageType(1));
+              static_cast<StorageType>(x_bits.get_mantissa() + StorageType(1)));
   }
 };
 
diff --git a/libc/test/src/math/smoke/NextTowardTest.h b/libc/test/src/math/smoke/NextTowardTest.h
index a24ec9f..5992273 100644
--- a/libc/test/src/math/smoke/NextTowardTest.h
+++ b/libc/test/src/math/smoke/NextTowardTest.h
@@ -9,16 +9,15 @@
 #ifndef LLVM_LIBC_TEST_SRC_MATH_NEXTTOWARDTEST_H
 #define LLVM_LIBC_TEST_SRC_MATH_NEXTTOWARDTEST_H
 
-#include "hdr/fenv_macros.h"
-#include "hdr/math_macros.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 "test/UnitTest/FEnvSafeTest.h"
 #include "test/UnitTest/FPMatcher.h"
 #include "test/UnitTest/Test.h"
 
+#include "hdr/fenv_macros.h"
+
 // TODO: Strengthen errno,exception checks and remove these assert macros
 // after new matchers/test fixtures are added
 #define ASSERT_FP_EQ_WITH_EXCEPTION(result, expected, expected_exception)      \
@@ -194,7 +193,7 @@ public:
     result_bits = FPBits(result);
     ASSERT_EQ(result_bits.get_biased_exponent(), x_bits.get_biased_exponent());
     ASSERT_EQ(result_bits.get_mantissa(),
-              x_bits.get_mantissa() + StorageType(1));
+              static_cast<StorageType>(x_bits.get_mantissa() + StorageType(1)));
 
     x = -x;
 
@@ -208,7 +207,7 @@ public:
     result_bits = FPBits(result);
     ASSERT_EQ(result_bits.get_biased_exponent(), x_bits.get_biased_exponent());
     ASSERT_EQ(result_bits.get_mantissa(),
-              x_bits.get_mantissa() + StorageType(1));
+              static_cast<StorageType>(x_bits.get_mantissa() + StorageType(1)));
   }
 };
 
diff --git a/libc/test/src/math/smoke/nextafterf16_test.cpp b/libc/test/src/math/smoke/nextafterf16_test.cpp
new file mode 100644
index 0000000..860a0c7
--- /dev/null
+++ b/libc/test/src/math/smoke/nextafterf16_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for nextafterf16 ----------------------------------------===//
+//
+// 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 "NextAfterTest.h"
+
+#include "src/math/nextafterf16.h"
+
+LIST_NEXTAFTER_TESTS(float16, LIBC_NAMESPACE::nextafterf16)
diff --git a/libc/test/src/math/smoke/nextdownf16_test.cpp b/libc/test/src/math/smoke/nextdownf16_test.cpp
new file mode 100644
index 0000000..353f085
--- /dev/null
+++ b/libc/test/src/math/smoke/nextdownf16_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for nextdownf16 -----------------------------------------===//
+//
+// 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 "NextDownTest.h"
+
+#include "src/math/nextdownf16.h"
+
+LIST_NEXTDOWN_TESTS(float16, LIBC_NAMESPACE::nextdownf16)
diff --git a/libc/test/src/math/smoke/nexttowardf16_test.cpp b/libc/test/src/math/smoke/nexttowardf16_test.cpp
new file mode 100644
index 0000000..8490e8d
--- /dev/null
+++ b/libc/test/src/math/smoke/nexttowardf16_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for nexttowardf16 ---------------------------------------===//
+//
+// 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 "NextTowardTest.h"
+
+#include "src/math/nexttowardf16.h"
+
+LIST_NEXTTOWARD_TESTS(float16, LIBC_NAMESPACE::nexttowardf16)
diff --git a/libc/test/src/math/smoke/nextupf16_test.cpp b/libc/test/src/math/smoke/nextupf16_test.cpp
new file mode 100644
index 0000000..a146d27
--- /dev/null
+++ b/libc/test/src/math/smoke/nextupf16_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for nextupf16 -------------------------------------------===//
+//
+// 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 "NextUpTest.h"
+
+#include "src/math/nextupf16.h"
+
+LIST_NEXTUP_TESTS(float16, LIBC_NAMESPACE::nextupf16)