[Bug c/67680] Seg Fault in gcc 4.9.3 compiling libiberty/floatformat.c when building gcc 5.2.1 on Cygwin 64 on Windows

["bplummer at hotmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67680

--- Comment #4 from Brian Plummer <bplummer at hotmail dot com> ---
I had these comments in my message, but they got lost when I added my
attachment.

floatformat.preprocessed.c was created with this command :

Brian@MBPWin7-64 ~/gnu/gcc/gcc-5.2.0/libiberty
$ gcc -E -c -DHAVE_CONFIG_H -g  -I. -I../build/libiberty/ -I../include  -W
-Wall -Wwrite-strings -Wc++-compat -Wstrict-prototypes -pedantic  floatformat.c
-o floatformat.preprocessed.c

compiling floatformat.preprocessed.c :

Brian@MBPWin7-64 ~/gnu/gcc/gcc-5.2.0/libiberty
$ gcc -c floatformat.preprocessed.c -o floatformat.o
floatformat.c: In function âfloatformat_to_doubleâ:
floatformat.c:529:2: internal compiler error: Segmentation fault
  dto = ldexp (1.0, exponent);
  ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Machine and compiler details are in an earlier post.