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 #include "src/__support/FPUtil/FPBits.h"
  10
  11 #include <math.h>
  12 #include <stddef.h>
  13 #include <stdint.h>
  14
  15 template <typename T> using RemQuoFunc = T (*)(T, T, int *);
  16
  17 template <typename T>
  18 void RemQuoDiff(RemQuoFunc<T> func1, RemQuoFunc<T> func2, const uint8_t *data,
  19                 size_t size) {
  20   constexpr size_t typeSize = sizeof(T);
  21   if (size < 2 * typeSize)
  22     return;
  23
  24   T x = *reinterpret_cast<const T *>(data);
  25   T y = *reinterpret_cast<const T *>(data + typeSize);
  26
  27   int q1, q2;
  28   T remainder1 = func1(x, y, &q1);
  29   T remainder2 = func2(x, y, &q2);
  30
  31   if (isnan(remainder1)) {
  32     if (!isnan(remainder2))
  33       __builtin_trap();
  34     return;
  35   }
  36
  37   if (isinf(remainder2) != isinf(remainder1))
  38     __builtin_trap();
  39
  40   // Compare only the 3 LS bits of the quotient.
  41   if ((q1 & 0x7) != (q2 & 0x7))
  42     __builtin_trap();
  43
  44   __llvm_libc::fputil::FPBits<T> bits1(remainder1);
  45   __llvm_libc::fputil::FPBits<T> bits2(remainder2);
  46   if (bits1.uintval() != bits2.uintval())
  47     __builtin_trap();
  48 }