[libc][math][c23] Add fdimf16 C23 math function (#94354)

#93566

3 files changed, 37 insertions, 9 deletions

diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 6b70d89..09e54349 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -1635,7 +1635,7 @@ add_fp_unittest(
     FDimTest.h
   DEPENDS
     libc.src.math.fdimf
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.algorithm
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -1649,7 +1649,7 @@ add_fp_unittest(
     FDimTest.h
   DEPENDS
     libc.src.math.fdim
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.algorithm
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -1663,7 +1663,21 @@ add_fp_unittest(
     FDimTest.h
   DEPENDS
     libc.src.math.fdiml
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.FPUtil.fp_bits
+)
+
+add_fp_unittest(
+  fdimf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    fdimf16_test.cpp
+  HDRS
+    FDimTest.h
+  DEPENDS
+    libc.src.math.fdimf16
+    libc.src.__support.CPP.algorithm
     libc.src.__support.FPUtil.fp_bits
 )
 
@@ -1677,7 +1691,7 @@ add_fp_unittest(
     FDimTest.h
   DEPENDS
     libc.src.math.fdimf128
-    libc.src.__support.FPUtil.basic_operations
+    libc.src.__support.CPP.algorithm
     libc.src.__support.FPUtil.fp_bits
 )
 
diff --git a/libc/test/src/math/smoke/FDimTest.h b/libc/test/src/math/smoke/FDimTest.h
index cff88f2..cc0ce3b 100644
--- a/libc/test/src/math/smoke/FDimTest.h
+++ b/libc/test/src/math/smoke/FDimTest.h
@@ -6,7 +6,7 @@
 //
 //===---------------------------------------------------------------------===//
 
-#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/CPP/algorithm.h"
 #include "src/__support/FPUtil/FPBits.h"
 #include "test/UnitTest/FEnvSafeTest.h"
 #include "test/UnitTest/FPMatcher.h"
@@ -61,10 +61,11 @@ public:
   void test_in_range(FuncPtr func) {
     constexpr StorageType STORAGE_MAX =
         LIBC_NAMESPACE::cpp::numeric_limits<StorageType>::max();
-    constexpr StorageType COUNT = 100'001;
-    constexpr StorageType STEP = STORAGE_MAX / COUNT;
-    for (StorageType i = 0, v = 0, w = STORAGE_MAX; i <= COUNT;
-         ++i, v += STEP, w -= STEP) {
+    constexpr int COUNT = 100'001;
+    constexpr StorageType STEP = LIBC_NAMESPACE::cpp::max(
+        static_cast<StorageType>(STORAGE_MAX / COUNT), StorageType(1));
+    StorageType v = 0, w = STORAGE_MAX;
+    for (int i = 0; i <= COUNT; ++i, v += STEP, w -= STEP) {
       FPBits xbits(v), ybits(w);
       if (xbits.is_inf_or_nan())
         continue;
diff --git a/libc/test/src/math/smoke/fdimf16_test.cpp b/libc/test/src/math/smoke/fdimf16_test.cpp
new file mode 100644
index 0000000..f40fab3
--- /dev/null
+++ b/libc/test/src/math/smoke/fdimf16_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for fdimf16 ---------------------------------------------===//
+//
+// 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 "FDimTest.h"
+
+#include "src/math/fdimf16.h"
+
+LIST_FDIM_TESTS(float16, LIBC_NAMESPACE::fdimf16);