[libc][math] Implement issignaling macro.

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

@@ -20,5 +20,9 @@
   __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x)
 #define isnormal(x) __builtin_isnormal(x)
 #define issubnormal(x) (fpclassify(x) == FP_SUBNORMAL)
+#if (defined(__clang__) && __clang_major__ >= 18) ||                           \
+    (defined(__GNUC__) && __GNUC__ >= 13)
+#define issignaling(x) __builtin_issignaling(x)
+#endif
 
 #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(
+  issignaling_test
+  SUITE
+    libc_include_tests
+  SRCS
+    issignaling_test.cpp
+  DEPENDS
+    libc.include.llvm-libc-macros.math_function_macros
+)
+
+add_libc_test(
+  issignalingf_test
+  SUITE
+    libc_include_tests
+  SRCS
+    issignalingf_test.cpp
+  DEPENDS
+    libc.include.llvm-libc-macros.math_function_macros
+)
+
+add_libc_test(
+  issignalingl_test
+  SUITE
+    libc_include_tests
+  SRCS
+    issignalingl_test.cpp
+  DEPENDS
+    libc.include.llvm-libc-macros.math_function_macros
+)
+
 add_libc_test(
   issubnormal_test
   SUITE
@@ -366,6 +396,21 @@ add_libc_test(
     libc.include.llvm-libc-macros.math_function_macros
 )
 
+add_libc_test(
+  issignaling_c_test
+  C_TEST
+  UNIT_TEST_ONLY
+  SUITE
+    libc_include_tests
+  SRCS
+    issignaling_test.c
+  COMPILE_OPTIONS
+    -Wall
+    -Werror
+  DEPENDS
+    libc.include.llvm-libc-macros.math_function_macros
+)
+
 add_libc_test(
   isinf_c_test
   C_TEST

libc/test/include/IsSignalingTest.h

@@ -0,0 +1,49 @@
+//===-- Utility class to test the issignaling 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_ISSIGNALING_H
+#define LLVM_LIBC_TEST_INCLUDE_MATH_ISSIGNALING_H
+
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+template <typename T>
+class IsSignalingTest : public LIBC_NAMESPACE::testing::Test {
+  DECLARE_SPECIAL_CONSTANTS(T)
+
+public:
+  typedef int (*IsSignalingFunc)(T);
+
+  void testSpecialNumbers(IsSignalingFunc func) {
+    EXPECT_EQ(func(aNaN), 0);
+    EXPECT_EQ(func(neg_aNaN), 0);
+    EXPECT_EQ(func(sNaN), 1);
+    EXPECT_EQ(func(neg_sNaN), 1);
+    EXPECT_EQ(func(inf), 0);
+    EXPECT_EQ(func(neg_inf), 0);
+    EXPECT_EQ(func(min_normal), 0);
+    EXPECT_EQ(func(max_normal), 0);
+    EXPECT_EQ(func(neg_max_normal), 0);
+    EXPECT_EQ(func(min_denormal), 0);
+    EXPECT_EQ(func(neg_min_denormal), 0);
+    EXPECT_EQ(func(max_denormal), 0);
+    EXPECT_EQ(func(zero), 0);
+    EXPECT_EQ(func(neg_zero), 0);
+  }
+};
+
+#define LIST_ISSIGNALING_TESTS(T, func)                                        \
+  using LlvmLibcIsSignalingTest = IsSignalingTest<T>;                          \
+  TEST_F(LlvmLibcIsSignalingTest, SpecialNumbers) {                            \
+    auto issignaling_func = [](T x) { return func(x); };                       \
+    testSpecialNumbers(issignaling_func);                                      \
+  }
+
+#endif // LLVM_LIBC_TEST_INCLUDE_MATH_ISSIGNALING_H

libc/test/include/issignaling_test.c

@@ -0,0 +1,24 @@
+//===-- Unittests for issignaling 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>
+
+// TODO: enable the test unconditionally when issignaling macro is fixed for
+//       older compiler
+int main(void) {
+#ifdef issignaling
+  assert(issignaling(__builtin_nans("")) == 1);
+  assert(issignaling(__builtin_nansf("")) == 1);
+  assert(issignaling(__builtin_nansl("")) == 1);
+  assert(issignaling(1.819f) == 0);
+  assert(issignaling(-1.726) == 0);
+  assert(issignaling(1.426L) == 0);
+#endif
+  return 0;
+}

libc/test/include/issignaling_test.cpp

@@ -0,0 +1,18 @@
+//===-- Unittest for issignaling[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 "IsSignalingTest.h"
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+// TODO: enable the test unconditionally when issignaling macro is fixed for
+//       older compiler
+#ifdef issignaling
+LIST_ISSIGNALING_TESTS(double, issignaling)
+#else
+int main() { return 0; }
+#endif

libc/test/include/issignalingf_test.cpp

@@ -0,0 +1,18 @@
+//===-- Unittest for issignaling[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 "IsSignalingTest.h"
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+// TODO: enable the test unconditionally when issignaling macro is fixed for
+//       older compiler
+#ifdef issignaling
+LIST_ISSIGNALING_TESTS(float, issignaling)
+#else
+int main() { return 0; }
+#endif

libc/test/include/issignalingl_test.cpp

@@ -0,0 +1,18 @@
+//===-- Unittest for issignaling[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 "IsSignalingTest.h"
+#include "include/llvm-libc-macros/math-function-macros.h"
+
+// TODO: enable the test unconditionally when issignaling macro is fixed for
+//       older compiler
+#ifdef issignaling
+LIST_ISSIGNALING_TESTS(long double, issignaling)
+#else
+int main() { return 0; }
+#endif