Question on aggregates and GIMPLE

[Jason Merrill]

On Wed, 9 Jun 2004 17:27:50 -0700, Richard Henderson <rth@redhat.com> wrote:

> On Wed, Jun 09, 2004 at 08:20:31PM -0400, Richard Kenner wrote:
>>     <MODIFY_EXPR <INDIRECT_REF, INDIRECT_REF>> is valid GIMPLE, and shouldn't
>>     require a temporary.  I think we're just getting confused by the
>>     VIEW_CONVERT_EXPR.
>> 
>> Well, how about <MODIFY_EXPR <COMPONENT_REF, INDIRECT_REF>>?  It appears to
>> be saying that if the LHS is "complex", the RHS must be a variable and
>> trying to make a temporary.
>
> Hmm.  I don't suppose
>
>           || (flag_non_call_exceptions && tree_could_trap_p (*from_p))
>
> is true in gimplify_modify_expr?  If so, I'm not sure how to approach
> this.  Other languages require that MODIFY_EXPRs be atomic.

I was looking at this earlier today, and thinking that we should probably
disable this for aggregates, or at least for aggregate_value_p types.
Do you remember the case which inspired this check?

Jason