[libc][[math] Implement IsZero Macro

libc/include/llvm-libc-macros/math-function-macros.h

@@ -13,5 +13,6 @@
 #define isinf(x) __builtin_isinf(x)
 #define isnan(x) __builtin_isnan(x)
 #define signbit(x) __builtin_signbit(x)
+#define iszero(x) (x == 0)
 
 #endif // LLVM_LIBC_MACROS_MATH_FUNCTION_MACROS_H

libc/test/include/CMakeLists.txt

@@ -81,6 +81,36 @@ add_libc_test(
     libc.include.llvm-libc-macros.stdckdint_macros
 )
 
+add_libc_test(
+  iszero_test
+  SUITE
+    libc_include_tests
+  SRCS
+    iszero_test.cpp
+  DEPENDS
+    libc.include.llvm-libc-macros.math_function_macros
+)
+
+add_libc_test(
+  iszerof_test
+  SUITE
+    libc_include_tests
+  SRCS
+    iszerof_test.cpp
+  DEPENDS
+    libc.include.llvm-libc-macros.math_function_macros
+)
+
+add_libc_test(
+  iszerol_test
+  SUITE
+    libc_include_tests
+  SRCS
+    iszerol_test.cpp
+  DEPENDS
+    libc.include.llvm-libc-macros.math_function_macros
+)
+
 add_libc_test(
   signbit_test
   SUITE
@@ -260,3 +290,18 @@ add_libc_test(
   DEPENDS
     libc.include.llvm-libc-macros.math_function_macros
 )
+
+add_libc_test(
+  iszero_c_test
+  C_TEST
+  UNIT_TEST_ONLY
+  SUITE
+    libc_include_tests
+  SRCS
+    iszero_test.c
+  COMPILE_OPTIONS
+    -Wall
+    -Werror
+  DEPENDS
+    libc.include.llvm-libc-macros.math_function_macros
+)

libc/test/include/IsZeroTest.h

@@ -0,0 +1,38 @@
+//===-- Utility class to test the iszero macro  -----------------*- 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_INCLUDE_MATH_ISZERO_H
+#define LLVM_LIBC_TEST_INCLUDE_MATH_ISZERO_H
+
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+template <typename T> class IsZeroTest : public LIBC_NAMESPACE::testing::Test {
+  DECLARE_SPECIAL_CONSTANTS(T)
+
+public:
+  typedef bool (*IsZeroFunc)(T);
+
+  void testSpecialNumbers(IsZeroFunc func) {
+    EXPECT_FALSE(func(inf));
+    EXPECT_FALSE(func(neg_inf));
+    EXPECT_TRUE(func(zero));
+    EXPECT_TRUE(func(neg_zero));
+  }
+};
+
+#define LIST_ISZERO_TESTS(T, func)                                             \
+  using LlvmLibcIsZeroTest = IsZeroTest<T>;                                    \
+  TEST_F(LlvmLibcIsZeroTest, SpecialNumbers) {                                 \
+    auto iszero_func = [](T x) { return func(x); };                            \
+    testSpecialNumbers(iszero_func);                                           \
+  }
+
+#endif // LLVM_LIBC_TEST_INCLUDE_MATH_ISZERO_H

libc/test/include/iszero_test.c

@@ -0,0 +1,25 @@
+//===-- Unittests for iszero macro ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDSList-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+#include <assert.h>
+
+// check if macro is defined
+#ifndef iszero
+#error "iszero macro is not defined"
+#else
+int main(void) {
+  assert(iszero(1.0f) == 0);
+  assert(iszero(1.0) == 0);
+  assert(iszero(1.0L) == 0);
+  assert(iszero(0.0f) == 1);
+  assert(iszero(0.0) == 1);
+  assert(iszero(0.0L) == 1);
+  return 0;
+}
+#endif

libc/test/include/iszero_test.cpp

@@ -0,0 +1,12 @@
+//===-- Unittest for iszero[d] macro --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDSList-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "IsZeroTest.h"
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+LIST_ISZERO_TESTS(double, iszero)

libc/test/include/iszerof_test.cpp

@@ -0,0 +1,12 @@
+//===-- Unittest for iszero[f] macro --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDSList-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "IsZeroTest.h"
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+LIST_ISZERO_TESTS(float, iszero)

libc/test/include/iszerol_test.cpp

@@ -0,0 +1,12 @@
+//===-- Unittest for iszero[l] macro --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDSList-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "IsZeroTest.h"
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+LIST_ISZERO_TESTS(long double, iszero)