[libc][math][c23] Implement fmaxf16 function

Author: HendrikHuebner

libc/config/linux/aarch64/entrypoints.txt

@@ -500,6 +500,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
   list(APPEND TARGET_LIBM_ENTRYPOINTS
     # math.h C23 _Float16 entrypoints
     libc.src.math.fabsf16
+    libc.src.math.fmaxf16
   )
 endif()
 

libc/config/linux/x86_64/entrypoints.txt

@@ -533,6 +533,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
   list(APPEND TARGET_LIBM_ENTRYPOINTS
     # math.h C23 _Float16 entrypoints
     libc.src.math.fabsf16
+    libc.src.math.fmaxf16
   )
 endif()
 

libc/spec/stdc.td

@@ -417,6 +417,7 @@ def StdC : StandardSpec<"stdc"> {
           FunctionSpec<"fmaxf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<FloatType>]>,
           FunctionSpec<"fmaxl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>]>,
           GuardedFunctionSpec<"fmaxf128", RetValSpec<Float128Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT128">,
+          GuardedFunctionSpec<"fmaxf16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
 	  FunctionSpec<"fmaximum", RetValSpec<DoubleType>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>]>,
           FunctionSpec<"fmaximumf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<FloatType>]>,

libc/src/math/CMakeLists.txt

@@ -119,6 +119,7 @@ add_math_entrypoint_object(fmax)
 add_math_entrypoint_object(fmaxf)
 add_math_entrypoint_object(fmaxl)
 add_math_entrypoint_object(fmaxf128)
+add_math_entrypoint_object(fmaxf16)
 
 add_math_entrypoint_object(fmin)
 add_math_entrypoint_object(fminf)

libc/src/math/fmaxf16.h

@@ -0,0 +1,21 @@
+//===-- Implementation header for fmaxf16 -------------------------*- 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_FMAXF_H
+#define LLVM_LIBC_SRC_MATH_FMAXF_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 fmaxf16(float16 x, float16 y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_FMAXF16_H
+

libc/src/math/generic/CMakeLists.txt

@@ -1661,6 +1661,19 @@ add_entrypoint_object(
     -O3
 )
 
+add_entrypoint_object(
+  fmaxf16
+  SRCS
+    fmaxf16.cpp
+  HDRS
+    ../fmaxf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.basic_operations
+  COMPILE_OPTIONS
+    -O3
+)
+
 add_entrypoint_object(
   fmaximum
   SRCS

libc/src/math/generic/fmaxf16.cpp

@@ -0,0 +1,19 @@
+//===-- Unittest of fmaxf16 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/fmaxf16.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, fmaxf16, (float16 x, float16 y)) {
+  return fputil::fmax(x, y);
+}
+
+} // namespace LIBC_NAMESPACE

libc/test/src/math/smoke/CMakeLists.txt

@@ -1558,6 +1558,19 @@ add_fp_unittest(
     libc.src.__support.FPUtil.fp_bits
 )
 
+add_fp_unittest(
+  fmaxf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    fmaxf16_test.cpp
+  HDRS
+    FMaxTest.h
+  DEPENDS
+    libc.src.math.fmaxf16
+    libc.src.__support.FPUtil.fp_bits
+)
+
 add_fp_unittest(
   fmaximuml_test
   SUITE

libc/test/src/math/smoke/fmaxf16_test.cpp

@@ -0,0 +1,13 @@
+//===-- Unittests for fmaxf128 --------------------------------------------===//
+//
+// 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 "FMaxTest.h"
+
+#include "src/math/fmaxf16.h"
+
+LIST_FMAX_TESTS(float16, LIBC_NAMESPACE::fmaxf16)