c++/3620: GCC3.0 optimization on anonymous union causes ICE

[MAKINO Takaki <mak@is.s.u-tokyo.ac.jp>]

>Number:         3620
>Category:       c++
>Synopsis:       GCC3.0 optimization on anonymous union causes ICE
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-legal-code
>Submitter-Id:   net
>Arrival-Date:   Mon Jul 09 06:26:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Makino Takaki
>Release:        3.0
>Organization:
Tokyo Univ.
>Environment:
System: Linux tetley.is.s.u-tokyo.ac.jp 2.2.16-22enterprise #1 SMP Tue Aug 22 16:29:32 EDT 2000 i686 unknown
Architecture: i686
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ../configure --prefix=/home/users/mak/local/Linux-i686
>Description:
ICE occurs with the following code and -O option:
--------------------------------------test.cpp
void something(char *);

int main()
{
        union {
                char d[sizeof(int)];
                int ll;
        };
        something(d);
        return ll;
}
-----------------------------------------------
mak@tetley% gcc -v
Reading specs from /home/users/mak/local/Linux-i686/lib/gcc-lib/i686-pc-linux-gnu/3.0/specs
Configured with: ../configure --prefix=/home/users/mak/local/Linux-i686
Thread model: single
gcc version 3.0
mak@tetley% g++ -O hoge.cpp
hoge.cpp: In function `int main()':
hoge.cpp:12: Internal compiler error in elimination_effects, at reload1.c:2687
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL: http://www.gnu.org/software/gcc/bugs.html > for instructions.

>How-To-Repeat:
       See description. 
>Fix:
       Work around is to give a name to the union.

int main()
{
        union {
                char d[sizeof(int)];
                int ll;
        } some_name;
        something(some_name.d);
        return some_name.ll;
}

-- 
MAKINO Takaki <mak@is.s.u-tokyo.ac.jp>

>Release-Note:
>Audit-Trail:
>Unformatted: