libc/fuzzing/math/RemQuoDiff.h

   1 //===-- Template for diffing remquo results ---------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_FUZZING_MATH_REMQUO_H
  10 #define LLVM_LIBC_FUZZING_MATH_REMQUO_H
  11
  12 #include "src/__support/FPUtil/FPBits.h"
  13
  14 #include <math.h>
  15 #include <stddef.h>
  16 #include <stdint.h>
  17
  18 template <typename T> using RemQuoFunc = T (*)(T, T, int *);
  19
  20 template <typename T>
  21 void RemQuoDiff(RemQuoFunc<T> func1, RemQuoFunc<T> func2, const uint8_t *data,
  22                 size_t size) {
  23   constexpr size_t typeSize = sizeof(T);
  24   if (size < 2 * typeSize)
  25     return;
  26
  27   T x = *reinterpret_cast<const T *>(data);
  28   T y = *reinterpret_cast<const T *>(data + typeSize);
  29
  30   int q1, q2;
  31   T remainder1 = func1(x, y, &q1);
  32   T remainder2 = func2(x, y, &q2);
  33
  34   if (isnan(remainder1)) {
  35     if (!isnan(remainder2))
  36       __builtin_trap();
  37     return;
  38   }
  39
  40   if (isinf(remainder2) != isinf(remainder1))
  41     __builtin_trap();
  42
  43   // Compare only the 3 LS bits of the quotient.
  44   if ((q1 & 0x7) != (q2 & 0x7))
  45     __builtin_trap();
  46
  47   LIBC_NAMESPACE::fputil::FPBits<T> bits1(remainder1);
  48   LIBC_NAMESPACE::fputil::FPBits<T> bits2(remainder2);
  49   if (bits1.uintval() != bits2.uintval())
  50     __builtin_trap();
  51 }
  52
  53 #endif // LLVM_LIBC_FUZZING_MATH_REMQUO_H