Re: [PATCH] handle zero-sized constructor component if side effects

[Olivier Hainque <hainque at adacore dot com>]

Daniel Berlin wrote:
> Again, this is not quite what you want to do.

> This will cause you bugs, because nothing expects to see sets of zero
> sized fields, and it confuses things like subvars, regardless of whether
> they have side effects or not.
> 
> We should still throw the set away, we just need to execute the
> instructions in the constructor.
 
> You should be doing what gimplify_modify_expr does, which is to still
> place the *value* side of the constructor in the instruction stream,
> just don't assign it to anything.

 Humm, something like that: 

      /* For zero-sized fields, just add the value to the statement list if
	 there are side-effects and continue.  This can happen with calls to
	 functions returning a zero-sized type, which we shouldn't discard.
	 We must not emit an assignment in this case, as nothing expects to
	 see sets of zero sized fields downstream.  */
      if (zero_sized_field_decl (purpose))
	{
	  if (TREE_SIDE_EFFECTS (value))
	    gimplify_and_add (value, pre_p);

	  continue;
	}

 ? 

 Thanks for your feedback,

 Olivier