[Bug libstdc++/52765] -std=c++0x requires multilib for non-optimized libstdc++

["christophe.lyon at st dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52765

--- Comment #9 from christophe.lyon at st dot com 2012-03-30 08:39:19 UTC ---
(In reply to comment #2)
> (In reply to comment #0)
> > I am not sure this is really a bug (is building libstdc++ at -O0 supported?),
> 
> Yes, the --enable-libstdcxx-debug configure option builds an alternative
> libstdc++.so with -O0 (but I can't reproduce this when using that lib)

I have experimented with this configure option. I didn't know about it: what is
the intended way of using the debug libraries? I have add -L..../debug to my
link command, and I do reproduce the problem in this context:
- target arm-none-eabi
- --disable-shared

# Using default libs, built at -O2
$ arm-none-eabi-g++ cplx.cxx -o cplx.u -mcpu=cortex-a9 -std=c++0x
$ qemu-system-arm -semihosting -cpu cortex-a9 -nographic -kernel ./cplx.u
23
(23,101)

# Using debug libs, built at -O0
$ arm-none-eabi-g++ cplx.cxx -o cplx.u -mcpu=cortex-a9 -std=c++0x -L
.../lib/debug
$ qemu-system-arm -semihosting -cpu cortex-a9 -nographic -kernel ./cplx.u
23
(0,101)