[libc][math] Add MPFR unit tests for nearbyint{,f,l,f16} (#94479)

6 files changed, 230 insertions, 0 deletions

diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 1326d08..729d9fe 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -587,6 +587,66 @@ add_fp_unittest(
 )
 
 add_fp_unittest(
+  nearbyint_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    nearbyint_test.cpp
+  HDRS
+    NearbyIntTest.h
+  DEPENDS
+    libc.src.math.nearbyint
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.CPP.array
+)
+
+add_fp_unittest(
+  nearbyintf_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    nearbyintf_test.cpp
+  HDRS
+    NearbyIntTest.h
+  DEPENDS
+    libc.src.math.nearbyintf
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.CPP.array
+)
+
+add_fp_unittest(
+  nearbyintl_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    nearbyintl_test.cpp
+  HDRS
+    NearbyIntTest.h
+  DEPENDS
+    libc.src.math.nearbyintl
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.CPP.array
+)
+
+add_fp_unittest(
+  nearbyintf16_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    nearbyintf16_test.cpp
+  HDRS
+    NearbyIntTest.h
+  DEPENDS
+    libc.src.math.nearbyintf16
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.CPP.array
+)
+
+add_fp_unittest(
   rint_test
   NEED_MPFR
   SUITE
diff --git a/libc/test/src/math/NearbyIntTest.h b/libc/test/src/math/NearbyIntTest.h
new file mode 100644
index 0000000..88cdf45
--- /dev/null
+++ b/libc/test/src/math/NearbyIntTest.h
@@ -0,0 +1,118 @@
+//===-- Utility class to test different flavors of nearbyint ----*- 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_SRC_MATH_NEARBYINTTEST_H
+#define LLVM_LIBC_TEST_SRC_MATH_NEARBYINTTEST_H
+
+#include "src/__support/CPP/algorithm.h"
+#include "src/__support/CPP/array.h"
+#include "test/UnitTest/FEnvSafeTest.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+using namespace LIBC_NAMESPACE::fputil::testing;
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+template <typename T>
+class NearbyIntTestTemplate : public LIBC_NAMESPACE::testing::FEnvSafeTest {
+
+  DECLARE_SPECIAL_CONSTANTS(T)
+
+  static constexpr LIBC_NAMESPACE::cpp::array<RoundingMode, 4> ROUNDING_MODES =
+      {
+          RoundingMode::Upward,
+          RoundingMode::Downward,
+          RoundingMode::TowardZero,
+          RoundingMode::Nearest,
+      };
+
+  static constexpr StorageType MIN_SUBNORMAL =
+      FPBits::min_subnormal().uintval();
+  static constexpr StorageType MAX_SUBNORMAL =
+      FPBits::max_subnormal().uintval();
+  static constexpr StorageType MIN_NORMAL = FPBits::min_normal().uintval();
+  static constexpr StorageType MAX_NORMAL = FPBits::max_normal().uintval();
+
+public:
+  using NearbyIntFunc = T (*)(T);
+
+  void test_round_numbers(NearbyIntFunc func) {
+    for (RoundingMode mode : ROUNDING_MODES) {
+      if (ForceRoundingMode r(mode); r.success) {
+        EXPECT_FP_EQ(func(T(1.0)), mpfr::round(T(1.0), mode));
+        EXPECT_FP_EQ(func(T(-1.0)), mpfr::round(T(-1.0), mode));
+        EXPECT_FP_EQ(func(T(10.0)), mpfr::round(T(10.0), mode));
+        EXPECT_FP_EQ(func(T(-10.0)), mpfr::round(T(-10.0), mode));
+        EXPECT_FP_EQ(func(T(1234.0)), mpfr::round(T(1234.0), mode));
+        EXPECT_FP_EQ(func(T(-1234.0)), mpfr::round(T(-1234.0), mode));
+      }
+    }
+  }
+
+  void test_fractions(NearbyIntFunc func) {
+    for (RoundingMode mode : ROUNDING_MODES) {
+      if (ForceRoundingMode r(mode); r.success) {
+        EXPECT_FP_EQ(func(T(0.5)), mpfr::round(T(0.5), mode));
+        EXPECT_FP_EQ(func(T(-0.5)), mpfr::round(T(-0.5), mode));
+        EXPECT_FP_EQ(func(T(0.115)), mpfr::round(T(0.115), mode));
+        EXPECT_FP_EQ(func(T(-0.115)), mpfr::round(T(-0.115), mode));
+        EXPECT_FP_EQ(func(T(0.715)), mpfr::round(T(0.715), mode));
+        EXPECT_FP_EQ(func(T(-0.715)), mpfr::round(T(-0.715), mode));
+      }
+    }
+  }
+
+  void test_subnormal_range(NearbyIntFunc func) {
+    constexpr int COUNT = 100'001;
+    const StorageType STEP = LIBC_NAMESPACE::cpp::max(
+        static_cast<StorageType>((MAX_SUBNORMAL - MIN_SUBNORMAL) / COUNT),
+        StorageType(1));
+    for (StorageType i = MIN_SUBNORMAL; i <= MAX_SUBNORMAL; i += STEP) {
+      T x = FPBits(i).get_val();
+      for (RoundingMode mode : ROUNDING_MODES) {
+        if (ForceRoundingMode r(mode); r.success) {
+          EXPECT_FP_EQ(func(x), mpfr::round(x, mode));
+        }
+      }
+    }
+  }
+
+  void test_normal_range(NearbyIntFunc func) {
+    constexpr int COUNT = 100'001;
+    const StorageType STEP = LIBC_NAMESPACE::cpp::max(
+        static_cast<StorageType>((MAX_NORMAL - MIN_NORMAL) / COUNT),
+        StorageType(1));
+    for (StorageType i = MIN_NORMAL; i <= MAX_NORMAL; i += STEP) {
+      FPBits xbits(i);
+      T x = xbits.get_val();
+      // In normal range on x86 platforms, the long double implicit 1 bit can be
+      // zero making the numbers NaN. We will skip them.
+      if (xbits.is_nan())
+        continue;
+
+      for (RoundingMode mode : ROUNDING_MODES) {
+        if (ForceRoundingMode r(mode); r.success) {
+          EXPECT_FP_EQ(func(x), mpfr::round(x, mode));
+        }
+      }
+    }
+  }
+};
+
+#define LIST_NEARBYINT_TESTS(F, func)                                          \
+  using LlvmLibcNearbyIntTest = NearbyIntTestTemplate<F>;                      \
+  TEST_F(LlvmLibcNearbyIntTest, RoundNumbers) { test_round_numbers(&func); }   \
+  TEST_F(LlvmLibcNearbyIntTest, Fractions) { test_fractions(&func); }          \
+  TEST_F(LlvmLibcNearbyIntTest, SubnormalRange) {                              \
+    test_subnormal_range(&func);                                               \
+  }                                                                            \
+  TEST_F(LlvmLibcNearbyIntTest, NormalRange) { test_normal_range(&func); }
+
+#endif // LLVM_LIBC_TEST_SRC_MATH_NEARBYINTTEST_H
diff --git a/libc/test/src/math/nearbyint_test.cpp b/libc/test/src/math/nearbyint_test.cpp
new file mode 100644
index 0000000..11a5c33
--- /dev/null
+++ b/libc/test/src/math/nearbyint_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for nearbyint -------------------------------------------===//
+//
+// 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 "NearbyIntTest.h"
+
+#include "src/math/nearbyint.h"
+
+LIST_NEARBYINT_TESTS(double, LIBC_NAMESPACE::nearbyint)
diff --git a/libc/test/src/math/nearbyintf16_test.cpp b/libc/test/src/math/nearbyintf16_test.cpp
new file mode 100644
index 0000000..e6ec250
--- /dev/null
+++ b/libc/test/src/math/nearbyintf16_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for nearbyintf16 ----------------------------------------===//
+//
+// 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 "NearbyIntTest.h"
+
+#include "src/math/nearbyintf16.h"
+
+LIST_NEARBYINT_TESTS(float16, LIBC_NAMESPACE::nearbyintf16)
diff --git a/libc/test/src/math/nearbyintf_test.cpp b/libc/test/src/math/nearbyintf_test.cpp
new file mode 100644
index 0000000..fd26153
--- /dev/null
+++ b/libc/test/src/math/nearbyintf_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for nearbyintf ------------------------------------------===//
+//
+// 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 "NearbyIntTest.h"
+
+#include "src/math/nearbyintf.h"
+
+LIST_NEARBYINT_TESTS(float, LIBC_NAMESPACE::nearbyintf)
diff --git a/libc/test/src/math/nearbyintl_test.cpp b/libc/test/src/math/nearbyintl_test.cpp
new file mode 100644
index 0000000..a6d81a1
--- /dev/null
+++ b/libc/test/src/math/nearbyintl_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for nearbyintl ------------------------------------------===//
+//
+// 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 "NearbyIntTest.h"
+
+#include "src/math/nearbyintl.h"
+
+LIST_NEARBYINT_TESTS(long double, LIBC_NAMESPACE::nearbyintl)