1 files changed, 66 insertions, 0 deletions
diff --git a/libc/test/src/math/exp2m1f_test.cpp b/libc/test/src/math/exp2m1f_test.cpp
new file mode 100644
index 0000000..a0f0da8
--- /dev/null
+++ b/libc/test/src/math/exp2m1f_test.cpp
@@ -0,0 +1,66 @@
+//===-- Unittests for exp2m1f ---------------------------------------------===//
+//
+// 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 "include/llvm-libc-macros/math-macros.h"
+#include "src/__support/CPP/array.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/errno/libc_errno.h"
+#include "src/math/exp2m1f.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+#include <stdint.h>
+
+using LlvmLibcExp2m1fTest = LIBC_NAMESPACE::testing::FPTest<float>;
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+TEST_F(LlvmLibcExp2m1fTest, TrickyInputs) {
+  constexpr LIBC_NAMESPACE::cpp::array<float, 10> INPUTS = {
+      // EXP2M1F_EXCEPTS_LO
+      0x1.36dc8ep-36,
+      0x1.224936p-19,
+      0x1.d16d2p-20,
+      0x1.17949ep-14,
+      -0x1.9c3e1ep-38,
+      -0x1.4d89b4p-32,
+      -0x1.a6eac4p-10,
+      -0x1.e7526ep-6,
+      // EXP2M1F_EXCEPTS_HI
+      0x1.16a972p-1,
+      -0x1.9f12acp-5,
+  };
+
+  for (float x : INPUTS) {
+    LIBC_NAMESPACE::libc_errno = 0;
+    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2m1, x,
+                                   LIBC_NAMESPACE::exp2m1f(x), 0.5);
+  }
+}
+
+TEST_F(LlvmLibcExp2m1fTest, InFloatRange) {
+  constexpr uint32_t COUNT = 100'000;
+  constexpr uint32_t STEP = UINT32_MAX / COUNT;
+  for (uint32_t i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
+    float x = FPBits(v).get_val();
+    if (isnan(x) || isinf(x))
+      continue;
+    LIBC_NAMESPACE::libc_errno = 0;
+    float result = LIBC_NAMESPACE::exp2m1f(x);
+
+    // If the computation resulted in an error or did not produce valid result
+    // in the single-precision floating point range, then ignore comparing with
+    // MPFR result as MPFR can still produce valid results because of its
+    // wider precision.
+    if (isnan(result) || isinf(result) || LIBC_NAMESPACE::libc_errno != 0)
+      continue;
+    ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2m1, x,
+                                   LIBC_NAMESPACE::exp2m1f(x), 0.5);
+  }
+}