For the given testcase G++ emmits internal error message.
--- testcase (fail.cpp) -------------------------
struct C {
  long int d __attribute__((aligned(32)));
};

struct D : public virtual C {
};

--- g++ output ----------------------------------
fail.cpp:5: Internal compiler error in tree_low_cst, at tree.c:3471

Release:
gcc version 3.1 20020423 (prerelease)

Environment:
Red Hat Linux release 7.1 (Seawolf)
Kernel 2.4.2-2smp on a 2-processor i686
GCC configured for i686-pc-linux-gnu
No additional configure options

How-To-Repeat:
command line is:
    g++ -V3.1 -c fail.cpp