[Bug libstdc++/29286] [4.0/4.1/4.2/4.3 Regression] placement new does not change the dynamic type as it should

[mark at codesourcery dot com]

------- Comment #120 from mark at codesourcery dot com  2007-05-22 18:55 -------
Subject: Re:  [4.0/4.1/4.2/4.3 Regression] placement
 new does not change the dynamic type as it should

gdr at cs dot tamu dot edu wrote:

> |  I would guess
> | that we made this change around the year 2000.  So, there's a large body
> | of code that conforms to the requirements of the aggressive
> | interpretation.
> 
> Yes; those programs will continue to be conformant.

Indeed -- but that's not the point I was trying to make.  The point is
that your changes would force G++ to generate inferior code -- for a
codebase that already works with the more aggressive interpretation.

In other words, from a GNU "product marketing" point of view, rather
than from a C++ language standards point of view, the change you want to
make is just going to hurt our users, who have made their code work with
the aggressive interpretation.  It's only going to help people moving to
G++ from other compilers that do not use the aggressive interpretation.
 And, we already have -fno-strict-aliasing for those folks.

I'm not trying to tell you not to make the argument that you think is
best for C++ as a language; obviously, that's your right.  I'm just
pointing out that the change you want to make probably isn't going to
help users who are already working with G++.

And, although I don't have the time/energy that you seem to have to work
on these standards issues, I do plan to oppose your interpretation on
the reflector.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29286