[libc] Fuzz tests for fsqrt, f16sqrt, and hypot (#150489)

Added fuzz tests for f16sqrt, fsqrt, and hypot

---------

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

1 files changed, 56 insertions, 0 deletions

diff --git a/libc/fuzzing/math/f16sqrt_fuzz.cpp b/libc/fuzzing/math/f16sqrt_fuzz.cpp
new file mode 100644
index 000000000000..9a097a555305
--- /dev/null
+++ b/libc/fuzzing/math/f16sqrt_fuzz.cpp
@@ -0,0 +1,56 @@
+//===-- f16sqrt_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 f16sqrt implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/math/f16sqrt.h"
+#include "utils/MPFRWrapper/mpfr_inc.h"
+#include <cstdint>
+#include <cstring>
+#include <iostream>
+#include <math.h>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  mpfr_t input;
+  mpfr_t out;
+  mpfr_init2(input, 53);
+  mpfr_init2(out, 128);
+  for (size_t i = 0; i < size / sizeof(double); ++i) {
+    double x;
+    std::memcpy(&x, data, sizeof(double));
+    data += sizeof(double);
+
+    // remove NaN, inf, and values outside the accepted range
+    if (isnan(x) || isinf(x) || x < 0)
+      continue;
+    // signed zeros already tested in unit tests
+    if (signbit(x) && x == 0.0)
+      continue;
+
+    mpfr_set_d(input, x, MPFR_RNDN);
+    mpfr_sqrt(out, input, MPFR_RNDN);
+    float16 to_compare = mpfr_get_d(out, MPFR_RNDN);
+
+    float16 result = LIBC_NAMESPACE::f16sqrt(x);
+
+    if (result != to_compare) {
+      std::cout << std::hexfloat << "Failing input: " << x << std::endl;
+      std::cout << std::hexfloat
+                << "Failing output: " << static_cast<float>(result)
+                << std::endl;
+      std::cout << std::hexfloat
+                << "Expected: " << static_cast<float>(to_compare) << std::endl;
+      __builtin_trap();
+    }
+  }
+  mpfr_clear(input);
+  mpfr_clear(out);
+  return 0;
+}