more on the C++ abstraction penalty

[Joe Buck]

I wrote:

> | gcc 2.95.2 does very well on the Stepanov abstraction penalty benchmark.
> | This is misleading.  The reason is that every "abstract object" in the
> | Stepanov test is reference to a builtin type or a one-element struct,
> | and these are handled very nicely by a special optimization we've been
> | calling ADDRESSOF.
> 
> [...]
> 
> | We should be able to get huge performance gains for a lot of C++ code with
> | this kind of mechanism.

Your editing here might unintentionally suggest that "this kind of
mechanism" was referring to ADDRESSOF.

Gaby writes:

> All these sound reasonable and should have been retained as release
> criteria. 

The release criteria currently only specify nonregression against 2.95.2,
it would suffice to just get ADDRESSOF working again to meet them (current
snapshots are not releasable for this reason).  The extra pass on the
trees would be an improvement, and not that hard to implement.