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

[overmighty]

No description provided.

[overmighty]

cc @lntue

Based on #94473.

[overmighty]

Would it be worth it to also use EXPECT_FP_EQ_WITH_EXCEPTION here based on the mantissa of x/xbits?

[overmighty]

Marking as draft until #94383 is relanded.

[overmighty]

cc @lntue

[llvmbot]

@llvm/pr-subscribers-libc

Author: OverMighty (overmighty)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/94479.diff

6 Files Affected:

• (modified) libc/test/src/math/CMakeLists.txt (+64)
• (added) libc/test/src/math/NearbyIntTest.h (+128)
• (added) libc/test/src/math/nearbyint_test.cpp (+13)
• (added) libc/test/src/math/nearbyintf16_test.cpp (+13)
• (added) libc/test/src/math/nearbyintf_test.cpp (+13)
• (added) libc/test/src/math/nearbyintl_test.cpp (+13)

diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index ba588662f469e..aaf1009ba0f75 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -574,6 +574,70 @@ add_fp_unittest(
     libc.src.__support.FPUtil.fp_bits
 )
 
+add_fp_unittest(
+  nearbyint_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    nearbyint_test.cpp
+  HDRS
+    NearbyIntTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.math.nearbyint
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.FPUtil.fenv_impl
+)
+
+add_fp_unittest(
+  nearbyintf_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    nearbyintf_test.cpp
+  HDRS
+    NearbyIntTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.math.nearbyintf
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.FPUtil.fenv_impl
+)
+
+add_fp_unittest(
+  nearbyintl_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    nearbyintl_test.cpp
+  HDRS
+    NearbyIntTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.math.nearbyintl
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.FPUtil.fenv_impl
+)
+
+add_fp_unittest(
+  nearbyintf16_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    nearbyintf16_test.cpp
+  HDRS
+    NearbyIntTest.h
+  DEPENDS
+    libc.hdr.fenv_macros
+    libc.src.math.nearbyintf16
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.FPUtil.fenv_impl
+)
+
 add_fp_unittest(
   rint_test
   NEED_MPFR
diff --git a/libc/test/src/math/NearbyIntTest.h b/libc/test/src/math/NearbyIntTest.h
new file mode 100644
index 0000000000000..fabe4bf00e150
--- /dev/null
+++ b/libc/test/src/math/NearbyIntTest.h
@@ -0,0 +1,128 @@
+//===-- 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/FPUtil/FEnvImpl.h"
+#include "test/UnitTest/FEnvSafeTest.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+#include "hdr/fenv_macros.h"
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+template <typename T>
+class NearbyIntTestTemplate : public LIBC_NAMESPACE::testing::FEnvSafeTest {
+
+  DECLARE_SPECIAL_CONSTANTS(T)
+
+  static constexpr int ROUNDING_MODES[4] = {FE_UPWARD, FE_DOWNWARD,
+                                            FE_TOWARDZERO, FE_TONEAREST};
+
+  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();
+
+  static mpfr::RoundingMode to_mpfr_rounding_mode(int mode) {
+    switch (mode) {
+    case FE_UPWARD:
+      return mpfr::RoundingMode::Upward;
+    case FE_DOWNWARD:
+      return mpfr::RoundingMode::Downward;
+    case FE_TOWARDZERO:
+      return mpfr::RoundingMode::TowardZero;
+    case FE_TONEAREST:
+      return mpfr::RoundingMode::Nearest;
+    default:
+      __builtin_unreachable();
+    }
+  }
+
+public:
+  using NearbyIntFunc = T (*)(T);
+
+  void test_round_numbers(NearbyIntFunc func) {
+    for (int mode : ROUNDING_MODES) {
+      LIBC_NAMESPACE::fputil::set_round(mode);
+      mpfr::RoundingMode mpfr_mode = to_mpfr_rounding_mode(mode);
+      EXPECT_FP_EQ(func(T(1.0)), mpfr::round(T(1.0), mpfr_mode));
+      EXPECT_FP_EQ(func(T(-1.0)), mpfr::round(T(-1.0), mpfr_mode));
+      EXPECT_FP_EQ(func(T(10.0)), mpfr::round(T(10.0), mpfr_mode));
+      EXPECT_FP_EQ(func(T(-10.0)), mpfr::round(T(-10.0), mpfr_mode));
+      EXPECT_FP_EQ(func(T(1234.0)), mpfr::round(T(1234.0), mpfr_mode));
+      EXPECT_FP_EQ(func(T(-1234.0)), mpfr::round(T(-1234.0), mpfr_mode));
+    }
+  }
+
+  void test_fractions(NearbyIntFunc func) {
+    for (int mode : ROUNDING_MODES) {
+      LIBC_NAMESPACE::fputil::set_round(mode);
+      mpfr::RoundingMode mpfr_mode = to_mpfr_rounding_mode(mode);
+      EXPECT_FP_EQ(func(T(0.5)), mpfr::round(T(0.5), mpfr_mode));
+      EXPECT_FP_EQ(func(T(-0.5)), mpfr::round(T(-0.5), mpfr_mode));
+      EXPECT_FP_EQ(func(T(0.115)), mpfr::round(T(0.115), mpfr_mode));
+      EXPECT_FP_EQ(func(T(-0.115)), mpfr::round(T(-0.115), mpfr_mode));
+      EXPECT_FP_EQ(func(T(0.715)), mpfr::round(T(0.715), mpfr_mode));
+      EXPECT_FP_EQ(func(T(-0.715)), mpfr::round(T(-0.715), mpfr_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 (int mode : ROUNDING_MODES) {
+        LIBC_NAMESPACE::fputil::set_round(mode);
+        mpfr::RoundingMode mpfr_mode = to_mpfr_rounding_mode(mode);
+        EXPECT_FP_EQ(func(x), mpfr::round(x, mpfr_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 (int mode : ROUNDING_MODES) {
+        LIBC_NAMESPACE::fputil::set_round(mode);
+        mpfr::RoundingMode mpfr_mode = to_mpfr_rounding_mode(mode);
+        EXPECT_FP_EQ(func(x), mpfr::round(x, mpfr_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 0000000000000..11a5c3372e73e
--- /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 0000000000000..e6ec250cec91f
--- /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 0000000000000..fd26153cfffb9
--- /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 0000000000000..a6d81a1439e17
--- /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)