Dwarf-2 support for the avr-target seems to be broken on head 4.0.0.

Dwarf-2 support for the avr-target seems to be broken on head 4.0.0.

[Björn Haase]

Hi,

some of you possibly remember that I had sent you a mail recently, stating 
that the avr port was broken again. A bug that I myself was not able to 
reproduce a couple of minutes later. I now have found the origin. It seems 
that there indeed is a bug:

I have just been checking out the entire gcc tree (head 4.0.0) and run a clean 
rebuild:

cd build_directory
rm -r *
../gcc/configure --target=avr --prefix=/home/bmh --disable-nls --with-dwarf2 
--enable-languages="c"
make all

(Note that I have used --with-dwarf2!) What I am getting is :-( :

../../gcc/gcc/libgcc2.c:535: internal compiler error: in simplify_subreg, at 
simplify-rtx.c:3671
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
make[2]: *** [libgcc/./_muldi3.o] Fehler 1
make[2]: Leaving directory `/home/bmh/gnucvs/head/build/gcc'
make[1]: *** [stmp-multilib] Fehler 2
make[1]: Leaving directory `/home/bmh/gnucvs/head/build/gcc'
make: *** [all-gcc] Fehler 2

When building head 4.0.0 without --with-dwarf2, the build succeeds. I have 
made the same observation with last week's snapshot on another build system.

Unfortunate thing is: dwarf-2 is the main debugging format for all the windows 
users that use the Atmel debugger (avr-gdb is so slow under cygwin that it is 
almost not useful to use it).
 
 Yours,

Björn