At least on Cygwin (1.7), the current GCC snapshot (20090917) fails to
build:
[...]
/tmp/build/./gcc/xgcc -B/tmp/build/./gcc/
-B/usr/local/gfortran/i686-pc-cygwin/bin/
-B/usr/local/gfortran/i686-pc-cygwin/lib/ -isystem
/usr/local/gfortran/i686-pc-cygwin/include -isystem
/usr/local/gfortran/i686-pc-cygwin/sys-include -g -O2 -O2
-I/tmp/gcc-4.5-20090917/gcc/../winsup/w32api/include
-I/tmp/gcc-4.5-20090917/gcc/../winsup/include
-I/tmp/gcc-4.5-20090917/gcc/../winsup/cygwin/include -g -O2 -DIN_GCC
-W -Wall -Wwrite-strings -Wcast-qual -Wstrict-prototypes
-Wmissing-prototypes -Wold-style-definition -isystem ./include -g
-DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -I. -I.
-I../.././gcc -I/tmp/gcc-4.5-20090917/libgcc
-I/tmp/gcc-4.5-20090917/libgcc/. -I/tmp/gcc-4.5-20090917/libgcc/../gcc
-I/tmp/gcc-4.5-20090917/libgcc/../include
-I/tmp/gcc-4.5-20090917/libgcc/../libdecnumber/dpd
-I/tmp/gcc-4.5-20090917/libgcc/../libdecnumber -DHAVE_CC_TLS -o
_powitf2.o -MT _powitf2.o -MD -MP -MF _powitf2.dep -DL_powitf2 -c
/tmp/gcc-4.5-20090917/libgcc/../gcc/libgcc2.c \
/tmp/gcc-4.5-20090917/libgcc/../gcc/libgcc2.c: In function '__powisf2':
/tmp/gcc-4.5-20090917/libgcc/../gcc/libgcc2.c:1739:1: internal
compiler error: in convert_regs_1, at reg-stack.c:3052
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
make[3]: *** [_powisf2.o] Error 1
make[3]: *** Waiting for unfinished jobs....
/tmp/gcc-4.5-20090917/libgcc/../gcc/libgcc2.c: In function '__powidf2':
/tmp/gcc-4.5-20090917/libgcc/../gcc/libgcc2.c:1739:1: internal
compiler error: in convert_regs_1, at reg-stack.c:3052
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
make[3]: *** [_powidf2.o] Error 1
/tmp/gcc-4.5-20090917/libgcc/../gcc/libgcc2.c: In function '__powixf2':
/tmp/gcc-4.5-20090917/libgcc/../gcc/libgcc2.c:1739:1: internal
compiler error: in convert_regs_1, at reg-stack.c:3052
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
make[3]: *** [_powixf2.o] Error 1
make[3]: Leaving directory `/tmp/build/i686-pc-cygwin/libgcc'
make[2]: *** [all-stage2-target-libgcc] Error 2
make[2]: Leaving directory `/tmp/build'
make[1]: *** [stage2-bubble] Error 2
make[1]: Leaving directory `/tmp/build'
make: *** [all] Error 2
-------------------------------------------------------
I have configured with:
-----
${source_dir}/configure --prefix="${prefix_dir}" \
--exec-prefix="${eprefix_dir}" \
--sysconfdir="${sysconf_dir}" \
--libdir="${lib_dir}" \
--libexecdir="${libexec_dir}" \
--mandir="${man_dir}" \
--infodir="${info_dir}" \
--program-suffix="${suffix}" \
--enable-bootstrap \
--enable-checking=release \
--enable-decimal-float \
--enable-languages=c,c++,fortran \
--enable-libgomp \
--enable-libssp \
--enable-nls \
--enable-threads=posix \
--enable-version-specific-runtime-libs \
--disable-libmudflap \
--disable-shared \
--disable-sjlj-exceptions \
--disable-win32-registry \
--with-arch=i686 \
--with-dwarf2 \
--with-system-zlib \
--with-tune=generic \
--without-included-gettext \
--without-x
-----
The previous snapshot (20090910) builds fine, with the same methods.