[libc][math][c23] Add copysignf16 C23 math function (#94351)

#93566

3 files changed, 37 insertions, 3 deletions

diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index b6a3f0b..6b70d89 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -995,6 +995,7 @@ add_fp_unittest(
     CopySignTest.h
   DEPENDS
     libc.src.math.copysign
+    libc.src.__support.CPP.algorithm
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -1008,6 +1009,7 @@ add_fp_unittest(
     CopySignTest.h
   DEPENDS
     libc.src.math.copysignf
+    libc.src.__support.CPP.algorithm
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -1021,6 +1023,21 @@ add_fp_unittest(
     CopySignTest.h
   DEPENDS
     libc.src.math.copysignl
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.FPUtil.fp_bits
+)
+
+add_fp_unittest(
+  copysignf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    copysignf16_test.cpp
+  HDRS
+    CopySignTest.h
+  DEPENDS
+    libc.src.math.copysignf16
+    libc.src.__support.CPP.algorithm
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -1034,6 +1051,7 @@ add_fp_unittest(
     CopySignTest.h
   DEPENDS
     libc.src.math.copysignf128
+    libc.src.__support.CPP.algorithm
     libc.src.__support.FPUtil.fp_bits
 )
 
diff --git a/libc/test/src/math/smoke/CopySignTest.h b/libc/test/src/math/smoke/CopySignTest.h
index 1810560..1eb323a 100644
--- a/libc/test/src/math/smoke/CopySignTest.h
+++ b/libc/test/src/math/smoke/CopySignTest.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_TEST_SRC_MATH_SMOKE_COPYSIGNTEST_H
 #define LLVM_LIBC_TEST_SRC_MATH_SMOKE_COPYSIGNTEST_H
 
+#include "src/__support/CPP/algorithm.h"
 #include "test/UnitTest/FEnvSafeTest.h"
 #include "test/UnitTest/FPMatcher.h"
 #include "test/UnitTest/Test.h"
@@ -35,9 +36,11 @@ public:
   }
 
   void testRange(CopySignFunc func) {
-    constexpr StorageType COUNT = 100'000;
-    constexpr StorageType STEP = STORAGE_MAX / COUNT;
-    for (StorageType i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
+    constexpr int COUNT = 100'000;
+    constexpr StorageType STEP = LIBC_NAMESPACE::cpp::max(
+        static_cast<StorageType>(STORAGE_MAX / COUNT), StorageType(1));
+    StorageType v = 0;
+    for (int i = 0; i <= COUNT; ++i, v += STEP) {
       FPBits x_bits = FPBits(v);
       T x = T(v);
       if (x_bits.is_nan() || x_bits.is_inf())
diff --git a/libc/test/src/math/smoke/copysignf16_test.cpp b/libc/test/src/math/smoke/copysignf16_test.cpp
new file mode 100644
index 0000000..80a67f1
--- /dev/null
+++ b/libc/test/src/math/smoke/copysignf16_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for copysignf16 -----------------------------------------===//
+//
+// 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 "CopySignTest.h"
+
+#include "src/math/copysignf16.h"
+
+LIST_COPYSIGN_TESTS(float16, LIBC_NAMESPACE::copysignf16)