This bug is still present in the 2011.03-0 milestone build.  It breaks the build of eglibc's libstdc++ (and therefore the construction of a cross toolchain) at -mcpu=pentium-m -Os, which is the tuning we've been using for our embedded device.

Adding -fomit-frame-pointer makes the ICE disappear:

build@ctbu-bld5:~$ /home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/./gcc/xgcc -shared-libgcc -B/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/./gcc -nostdinc++ -L/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/i686-cm-linux-gnu/libstdc++-v3/src -L/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/i686-cm-linux-gnu/libstdc++-v3/src/.libs -B/opt/x-tools/i686-cm-linux-gnu/i686-cm-linux-gnu/bin/ -B/opt/x-tools/i686-cm-linux-gnu/i686-cm-linux-gnu/lib/ -isystem /opt/x-tools/i686-cm-linux-gnu/i686-cm-linux-gnu/include -isystem /opt/x-tools/i686-cm-linux-gnu/i686-cm-linux-gnu/sys-include -I/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/i686-cm-linux-gnu/libstdc++-v3/include/i686-cm-linux-gnu -I/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/i686-cm-linux-gnu/libstdc++-v3/include -I/home/build/x-tools-x86/targets/src/gcc-linaro-4.5-2011.03-0/libstdc++-v3/libsupc++ -fno-implicit-templates -Wall -Wextra -Wwrite-strings -Wcast-qual -fdiagnostics-show-location=once -ffunction-sections -fdata-sections -g -Os -c /home/build/x-tools-x86/targets/src/gcc-linaro-4.5-2011.03-0/libstdc++-v3/src/ios_init.cc -o ios_init.o -fomit-frame-pointer

build@ctbu-bld5:~$ /home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/./gcc/xgcc -shared-libgcc -B/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/./gcc -nostdinc++ -L/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/i686-cm-linux-gnu/libstdc++-v3/src -L/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/i686-cm-linux-gnu/libstdc++-v3/src/.libs -B/opt/x-tools/i686-cm-linux-gnu/i686-cm-linux-gnu/bin/ -B/opt/x-tools/i686-cm-linux-gnu/i686-cm-linux-gnu/lib/ -isystem /opt/x-tools/i686-cm-linux-gnu/i686-cm-linux-gnu/include -isystem /opt/x-tools/i686-cm-linux-gnu/i686-cm-linux-gnu/sys-include -I/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/i686-cm-linux-gnu/libstdc++-v3/include/i686-cm-linux-gnu -I/home/build/x-tools-x86/targets/i686-cm-linux-gnu/build/build-cc/i686-cm-linux-gnu/libstdc++-v3/include -I/home/build/x-tools-x86/targets/src/gcc-linaro-4.5-2011.03-0/libstdc++-v3/libsupc++ -fno-implicit-templates -Wall -Wextra -Wwrite-strings -Wcast-qual -fdiagnostics-show-location=once -ffunction-sections -fdata-sections -g -Os -c /home/build/x-tools-x86/targets/src/gcc-linaro-4.5-2011.03-0/libstdc++-v3/src/ios_init.cc -o ios_init.o -fno-omit-frame-pointer
/home/build/x-tools-x86/targets/src/gcc-linaro-4.5-2011.03-0/libstdc++-v3/src/ios_init.cc: In destructor 'std::ios_base::Init::~Init()':
/home/build/x-tools-x86/targets/src/gcc-linaro-4.5-2011.03-0/libstdc++-v3/src/ios_init.cc:144:3: internal compiler error: in dwarf2out_begin_epilogue, at dwarf2out.c:2859
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.