PVS-Studio warning V550 for ffdshow

static void av_build_filter(....)
{
  ....
  x = M_PI * ((double)(i - center) -
              (double)ph / phase_count) * factor;
  if (x == 0) y = 1.0;
  else        y = sin(x) / x;
  ....
}

It's strange to expect 'x' to exactly equal 0 after all these calculations.

This suspicious code was found in ffdshow project by PVS-Studio static code analyzer.
Warning message is:
V550 An odd precise comparison: x == 0. It's probably better to use a comparison with defined precision: fabs(A - B) < Epsilon. resample2.cpp 166

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/