[libc] exp fuzz tests (#148086)

Created fuzz tests for exp functions

---------

Co-authored-by: Sriya Pratipati <sriyap@google.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/libc/fuzzing/math/exp10_fuzz.cpp b/libc/fuzzing/math/exp10_fuzz.cpp
new file mode 100644
index 0000000..2baef03
--- /dev/null
+++ b/libc/fuzzing/math/exp10_fuzz.cpp
@@ -0,0 +1,38 @@
+//===-- exp10_fuzz.cpp ----------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc exp10 implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/math/exp10.h"
+#include "utils/MPFRWrapper/mpfr_inc.h"
+#include <math.h>
+
+extern "C" int LLVMFuzzerTestOneInput(double x) {
+  // remove NaN and inf
+  if (isnan(x) || isinf(x))
+    return 0;
+  // signed zeros already tested in unit tests
+  if (signbit(x) && x == 0.0)
+    return 0;
+  mpfr_t input;
+  mpfr_init2(input, 53);
+  mpfr_set_d(input, x, MPFR_RNDN);
+  int output = mpfr_exp10(input, input, MPFR_RNDN);
+  mpfr_subnormalize(input, output, MPFR_RNDN);
+  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+
+  double result = LIBC_NAMESPACE::exp10(x);
+
+  if (result != to_compare)
+    __builtin_trap();
+
+  mpfr_clear(input);
+  return 0;
+}