C++ ABI: Reuse of tail padding

[Nathan Sidwell]

Mark Mitchell wrote:

> We have a problem here.

> Intel's compiler does not pack things into the tail padding.
> Neither, I expect, does HP's.
I would like to get hard data from more than the two compilers
you've verified.

> Technically, the G++ version is superior.  (It reduces space used by
> objects.)  On the other hand, it was basically impossible for
> implementors to figure out what was intended from the spec.
> 
> I think I would prefer to change G++, and drop this idea from the spec,
> even though it is an optimization.
Although using tail padding is neat, how many bytes would it
save in real programs? You only get it with structs of the form
	int i;
	char c;
or (on some non-i86 machines)
	double d;
	int i;

nathan
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