[libc] Combine all math differential fuzzers into one target.

Also added diffing of a few more math functions. Combining the diff check
for all of these functions helps us meet the OSS fuzz bar of a minimum of
100 program edges.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D91817

1 files changed, 40 insertions, 0 deletions

diff --git a/libc/fuzzing/math/TwoInputSingleOutputDiff.h b/libc/fuzzing/math/TwoInputSingleOutputDiff.h
new file mode 100644
index 000000000000..2888a5b76d71
--- /dev/null
+++ b/libc/fuzzing/math/TwoInputSingleOutputDiff.h
@@ -0,0 +1,40 @@
+//===-- Template to diff two-input-single-output functions ------*- 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_FUZZING_MATH_TWO_INPUT_SINGLE_OUTPUT_DIFF_H
+#define LLVM_LIBC_FUZZING_MATH_TWO_INPUT_SINGLE_OUTPUT_DIFF_H
+
+#include "fuzzing/math/Compare.h"
+#include "utils/FPUtil/FPBits.h"
+
+#include <math.h>
+#include <stddef.h>
+#include <stdint.h>
+
+template <typename T1, typename T2>
+using TwoInputSingleOutputFunc = T1 (*)(T1, T2);
+
+template <typename T1, typename T2>
+void TwoInputSingleOutputDiff(TwoInputSingleOutputFunc<T1, T2> func1,
+                              TwoInputSingleOutputFunc<T1, T2> func2,
+                              const uint8_t *data, size_t size) {
+  constexpr size_t t1Size = sizeof(T1);
+  if (size < t1Size + sizeof(T2))
+    return;
+
+  T1 x = *reinterpret_cast<const T1 *>(data);
+  T2 y = *reinterpret_cast<const T2 *>(data + t1Size);
+
+  T1 result1 = func1(x, y);
+  T1 result2 = func2(x, y);
+
+  if (!ValuesEqual(result1, result2))
+    __builtin_trap();
+}
+
+#endif // LLVM_LIBC_FUZZING_MATH_TWO_INPUT_SINGLE_OUTPUT_DIFF_H