internal compiler error: Segmentation fault

[FX]

> Platform: x86_64-pc-mingw32
> problem: the compiler always reports "internal compiler error: Segmentation fault" if with optimization. It works without optimization.

Minimum information we need to have a chance to work it out:
  -- When you mean "platform", is that build, host, target, or all three?
  -- How did you build your GMP/MPFR, and what version do you have for these?
  -- What is your version (svn revision number) of headers/crt?
  -- What are the sources used and how did you configure your
compiler? (ie, what is the output of "gfortran -v"?)
  -- Does the C compiler work with -O? Was there any such error when
building libgfortran? (you can get that information from your build
log, grepping for the Fortran files of libgfortran: f2c_specifics.F90,
dprod_r8.f90, selected_int_kind.f90 and selected_real_kind.f90, as
well as all the libgfortran/generated/*.F90 files)
  -- Have you contacted the mingw-win64 developers?
(https://sourceforge.net/mailarchive/forum.php?forum_name=mingw-w64-public)
  -- Do you have a debugger available to tell us where the segfault
occurs (or even more, what the backtrace is when crashing)?

Thanks,
FX