[tuples] Avoid copying in gimplifier

[Jan Hubicka]

> On 6/18/08 8:21 AM, Jan Hubicka wrote:
> 
> >	* gimplify.c (gimplify_modify_expr): Unshare only returned value when
> >	want_value is set instead of copying operands all the time.
> 
> This seems to have cause a bootstrap failure on x86_64:
> 
> /home/dnovillo/tuples/native.x86_64/bld/./prev-gcc/xgcc 
> -B/home/dnovillo/tuples/native.x86_64/bld/./prev-gcc/ 
> -B/home/dnovillo/tuples/native.x86_64/x86_64-unknown-linux-gnu/bin/ -c 
> -DHAVE_CONFIG_H -g -O2 -I. 
> -I/home/dnovillo/tuples/src.x86_64/libiberty/../include  -W -Wall 
> -Wwrite-strings -Wc++-compat -Wstrict-prototypes -pedantic 
> /home/dnovillo/tuples/src.x86_64/libiberty/concat.c -o concat.o
> /home/dnovillo/tuples/src.x86_64/libiberty/concat.c: In function 
> 'vconcat_length':
> /home/dnovillo/tuples/src.x86_64/libiberty/concat.c:210: error: 
> incorrect sharing of tree nodes args->overflow_arg_area = D.3338;
> 
> *args
> /home/dnovillo/tuples/src.x86_64/libiberty/concat.c:210: internal 
> compiler error: verify_stmts failed

This seems mine, I am looking into it...

Honza
> 
> 
> Diego.