[libc][math][c23] Add MPFR exhaustive test for fmodf16 (#94656)

3 files changed, 168 insertions, 16 deletions

diff --git a/libc/test/src/math/exhaustive/CMakeLists.txt b/libc/test/src/math/exhaustive/CMakeLists.txt
index 34df872..fb3596c 100644
--- a/libc/test/src/math/exhaustive/CMakeLists.txt
+++ b/libc/test/src/math/exhaustive/CMakeLists.txt
@@ -4,6 +4,10 @@ add_header_library(
   exhaustive_test
   HDRS
     exhaustive_test.h
+  DEPENDS
+    libc.src.__support.CPP.type_traits
+    libc.src.__support.FPUtil.fp_bits
+    libc.src.__support.macros.properties.types
 )
 
 add_fp_unittest(
@@ -278,6 +282,21 @@ add_fp_unittest(
 )
 
 add_fp_unittest(
+  fmodf16_test
+  NO_RUN_POSTBUILD
+  NEED_MPFR
+  SUITE
+    libc_math_exhaustive_tests
+  SRCS
+    fmodf16_test.cpp
+  DEPENDS
+    .exhaustive_test
+    libc.src.math.fmodf16
+  LINK_LIBRARIES
+    -lpthread
+)
+
+add_fp_unittest(
   coshf_test
   NO_RUN_POSTBUILD
   NEED_MPFR
diff --git a/libc/test/src/math/exhaustive/exhaustive_test.h b/libc/test/src/math/exhaustive/exhaustive_test.h
index 13e2727..6f0c78eb 100644
--- a/libc/test/src/math/exhaustive/exhaustive_test.h
+++ b/libc/test/src/math/exhaustive/exhaustive_test.h
@@ -8,6 +8,7 @@
 
 #include "src/__support/CPP/type_traits.h"
 #include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/macros/properties/types.h"
 #include "test/UnitTest/FPMatcher.h"
 #include "test/UnitTest/Test.h"
 #include "utils/MPFRWrapper/MPFRUtils.h"
@@ -68,9 +69,46 @@ struct UnaryOpChecker : public virtual LIBC_NAMESPACE::testing::Test {
   }
 };
 
+template <typename OutType, typename InType = OutType>
+using BinaryOp = OutType(InType, InType);
+
+template <typename OutType, typename InType, mpfr::Operation Op,
+          BinaryOp<OutType, InType> Func>
+struct BinaryOpChecker : public virtual LIBC_NAMESPACE::testing::Test {
+  using FloatType = InType;
+  using FPBits = LIBC_NAMESPACE::fputil::FPBits<FloatType>;
+  using StorageType = typename FPBits::StorageType;
+
+  // Check in a range, return the number of failures.
+  uint64_t check(StorageType x_start, StorageType x_stop, StorageType y_start,
+                 StorageType y_stop, mpfr::RoundingMode rounding) {
+    mpfr::ForceRoundingMode r(rounding);
+    if (!r.success)
+      return x_stop > x_start || y_stop > y_start;
+    StorageType xbits = x_start;
+    uint64_t failed = 0;
+    do {
+      FloatType x = FPBits(xbits).get_val();
+      StorageType ybits = y_start;
+      do {
+        FloatType y = FPBits(ybits).get_val();
+        mpfr::BinaryInput<FloatType> input{x, y};
+        bool correct = TEST_MPFR_MATCH_ROUNDING_SILENTLY(Op, input, Func(x, y),
+                                                         0.5, rounding);
+        failed += (!correct);
+        // Uncomment to print out failed values.
+        // if (!correct) {
+        //   EXPECT_MPFR_MATCH_ROUNDING(Op, input, Func(x, y), 0.5, rounding);
+        // }
+      } while (ybits++ < y_stop);
+    } while (xbits++ < x_stop);
+    return failed;
+  }
+};
+
 // Checker class needs inherit from LIBC_NAMESPACE::testing::Test and provide
 //   StorageType and check method.
-template <typename Checker>
+template <typename Checker, size_t Increment = 1 << 20>
 struct LlvmLibcExhaustiveMathTest
     : public virtual LIBC_NAMESPACE::testing::Test,
       public Checker {
@@ -78,12 +116,35 @@ struct LlvmLibcExhaustiveMathTest
   using FPBits = typename Checker::FPBits;
   using StorageType = typename Checker::StorageType;
 
-  static constexpr StorageType INCREMENT = (1 << 20);
+  void explain_failed_range(std::stringstream &msg, StorageType x_begin,
+                            StorageType x_end) {
+#ifdef LIBC_TYPES_HAS_FLOAT16
+    using T = LIBC_NAMESPACE::cpp::conditional_t<
+        LIBC_NAMESPACE::cpp::is_same_v<FloatType, float16>, float, FloatType>;
+#else
+    using T = FloatType;
+#endif
+
+    msg << x_begin << " to " << x_end << " [0x" << std::hex << x_begin << ", 0x"
+        << x_end << "), [" << std::hexfloat
+        << static_cast<T>(FPBits(x_begin).get_val()) << ", "
+        << static_cast<T>(FPBits(x_end).get_val()) << ")";
+  }
+
+  void explain_failed_range(std::stringstream &msg, StorageType x_begin,
+                            StorageType x_end, StorageType y_begin,
+                            StorageType y_end) {
+    msg << "x ";
+    explain_failed_range(msg, x_begin, x_end);
+    msg << ", y ";
+    explain_failed_range(msg, y_begin, y_end);
+  }
 
   // Break [start, stop) into `nthreads` subintervals and apply *check to each
   // subinterval in parallel.
-  void test_full_range(StorageType start, StorageType stop,
-                       mpfr::RoundingMode rounding) {
+  template <typename... T>
+  void test_full_range(mpfr::RoundingMode rounding, StorageType start,
+                       StorageType stop, T... extra_range_bounds) {
     int n_threads = std::thread::hardware_concurrency();
     std::vector<std::thread> thread_list;
     std::mutex mx_cur_val;
@@ -102,8 +163,8 @@ struct LlvmLibcExhaustiveMathTest
               return;
 
             range_begin = current_value;
-            if (stop >= INCREMENT && stop - INCREMENT >= current_value) {
-              range_end = current_value + INCREMENT;
+            if (stop >= Increment && stop - Increment >= current_value) {
+              range_end = current_value + Increment;
             } else {
               range_end = stop;
             }
@@ -120,15 +181,14 @@ struct LlvmLibcExhaustiveMathTest
             std::cout << msg.str() << std::flush;
           }
 
-          uint64_t failed_in_range =
-              Checker::check(range_begin, range_end, rounding);
+          uint64_t failed_in_range = Checker::check(
+              range_begin, range_end, extra_range_bounds..., rounding);
           if (failed_in_range > 0) {
             std::stringstream msg;
             msg << "Test failed for " << std::dec << failed_in_range
-                << " inputs in range: " << range_begin << " to " << range_end
-                << " [0x" << std::hex << range_begin << ", 0x" << range_end
-                << "), [" << std::hexfloat << FPBits(range_begin).get_val()
-                << ", " << FPBits(range_end).get_val() << ")\n";
+                << " inputs in range: ";
+            explain_failed_range(msg, start, stop, extra_range_bounds...);
+            msg << "\n";
             std::cerr << msg.str() << std::flush;
 
             failed.fetch_add(failed_in_range);
@@ -151,19 +211,46 @@ struct LlvmLibcExhaustiveMathTest
   void test_full_range_all_roundings(StorageType start, StorageType stop) {
     std::cout << "-- Testing for FE_TONEAREST in range [0x" << std::hex << start
               << ", 0x" << stop << ") --" << std::dec << std::endl;
-    test_full_range(start, stop, mpfr::RoundingMode::Nearest);
+    test_full_range(mpfr::RoundingMode::Nearest, start, stop);
 
     std::cout << "-- Testing for FE_UPWARD in range [0x" << std::hex << start
               << ", 0x" << stop << ") --" << std::dec << std::endl;
-    test_full_range(start, stop, mpfr::RoundingMode::Upward);
+    test_full_range(mpfr::RoundingMode::Upward, start, stop);
 
     std::cout << "-- Testing for FE_DOWNWARD in range [0x" << std::hex << start
               << ", 0x" << stop << ") --" << std::dec << std::endl;
-    test_full_range(start, stop, mpfr::RoundingMode::Downward);
+    test_full_range(mpfr::RoundingMode::Downward, start, stop);
 
     std::cout << "-- Testing for FE_TOWARDZERO in range [0x" << std::hex
               << start << ", 0x" << stop << ") --" << std::dec << std::endl;
-    test_full_range(start, stop, mpfr::RoundingMode::TowardZero);
+    test_full_range(mpfr::RoundingMode::TowardZero, start, stop);
+  };
+
+  void test_full_range_all_roundings(StorageType x_start, StorageType x_stop,
+                                     StorageType y_start, StorageType y_stop) {
+    std::cout << "-- Testing for FE_TONEAREST in x range [0x" << std::hex
+              << x_start << ", 0x" << x_stop << "), y range [0x" << y_start
+              << ", 0x" << y_stop << ") --" << std::dec << std::endl;
+    test_full_range(mpfr::RoundingMode::Nearest, x_start, x_stop, y_start,
+                    y_stop);
+
+    std::cout << "-- Testing for FE_UPWARD in x range [0x" << std::hex
+              << x_start << ", 0x" << x_stop << "), y range [0x" << y_start
+              << ", 0x" << y_stop << ") --" << std::dec << std::endl;
+    test_full_range(mpfr::RoundingMode::Upward, x_start, x_stop, y_start,
+                    y_stop);
+
+    std::cout << "-- Testing for FE_DOWNWARD in x range [0x" << std::hex
+              << x_start << ", 0x" << x_stop << "), y range [0x" << y_start
+              << ", 0x" << y_stop << ") --" << std::dec << std::endl;
+    test_full_range(mpfr::RoundingMode::Downward, x_start, x_stop, y_start,
+                    y_stop);
+
+    std::cout << "-- Testing for FE_TOWARDZERO in x range [0x" << std::hex
+              << x_start << ", 0x" << x_stop << "), y range [0x" << y_start
+              << ", 0x" << y_stop << ") --" << std::dec << std::endl;
+    test_full_range(mpfr::RoundingMode::TowardZero, x_start, x_stop, y_start,
+                    y_stop);
   };
 };
 
@@ -175,3 +262,8 @@ template <typename OutType, typename InType, mpfr::Operation Op,
           UnaryOp<OutType, InType> Func>
 using LlvmLibcUnaryNarrowingOpExhaustiveMathTest =
     LlvmLibcExhaustiveMathTest<UnaryOpChecker<OutType, InType, Op, Func>>;
+
+template <typename FloatType, mpfr::Operation Op, BinaryOp<FloatType> Func>
+using LlvmLibcBinaryOpExhaustiveMathTest =
+    LlvmLibcExhaustiveMathTest<BinaryOpChecker<FloatType, FloatType, Op, Func>,
+                               1 << 2>;
diff --git a/libc/test/src/math/exhaustive/fmodf16_test.cpp b/libc/test/src/math/exhaustive/fmodf16_test.cpp
new file mode 100644
index 0000000..067cec9
--- /dev/null
+++ b/libc/test/src/math/exhaustive/fmodf16_test.cpp
@@ -0,0 +1,41 @@
+//===-- Exhaustive test for fmodf16 ---------------------------------------===//
+//
+// 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 "exhaustive_test.h"
+#include "src/math/fmodf16.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+using LlvmLibcFmodf16ExhaustiveTest =
+    LlvmLibcBinaryOpExhaustiveMathTest<float16, mpfr::Operation::Fmod,
+                                       LIBC_NAMESPACE::fmodf16>;
+
+// Range: [0, Inf];
+static constexpr uint16_t POS_START = 0x0000U;
+static constexpr uint16_t POS_STOP = 0x7c00U;
+
+// Range: [-Inf, 0];
+static constexpr uint16_t NEG_START = 0x8000U;
+static constexpr uint16_t NEG_STOP = 0xfc00U;
+
+TEST_F(LlvmLibcFmodf16ExhaustiveTest, PostivePositiveRange) {
+  test_full_range_all_roundings(POS_START, POS_STOP, POS_START, POS_STOP);
+}
+
+TEST_F(LlvmLibcFmodf16ExhaustiveTest, PostiveNegativeRange) {
+  test_full_range_all_roundings(POS_START, POS_STOP, NEG_START, NEG_STOP);
+}
+
+TEST_F(LlvmLibcFmodf16ExhaustiveTest, NegativePositiveRange) {
+  test_full_range_all_roundings(NEG_START, NEG_STOP, POS_START, POS_STOP);
+}
+
+TEST_F(LlvmLibcFmodf16ExhaustiveTest, NegativeNegativeRange) {
+  test_full_range_all_roundings(NEG_START, NEG_STOP, POS_START, POS_STOP);
+}