Replacing DCHECK_OP()'s implementation with DCHECK((val1) op (val2)) in a debug build gives two compilation errors in net/quic:

https://code.google.com/p/chromium/codesearch#chromium/src/net/quic/quic_data_reader.cc&q=quic_data_reader.c&sq=package:chromium&l=57
  bool QuicDataReader::ReadUFloat16(uint64_t* result) {
    uint16_t value;
    if (!ReadUInt16(&value)) {
      return false;
    }
    ...
    *result -= exponent << kUFloat16MantissaBits;
    *result <<= exponent;
    DCHECK_GE(value, 1 << kUFloat16MantissaEffectiveBits);
->  DCHECK_LE(value, kUFloat16MaxValue);
    return true;
  }

https://code.google.com/p/chromium/codesearch#chromium/src/net/quic/quic_protocol.cc&q=quic_protocol.cc&sq=package:chromium&l=312
  QuicRstStreamFrame::QuicRstStreamFrame(QuicStreamId stream_id,
                                         QuicRstStreamErrorCode error_code,
                                         QuicStreamOffset bytes_written)
      : stream_id(stream_id), error_code(error_code), byte_offset(bytes_written) {
->  DCHECK_LE(error_code, numeric_limits<uint8_t>::max());
  }