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

[rguenther at suse dot de]

------- Comment #172 from rguenther at suse dot de  2007-06-08 13:47 -------
Subject: Re:  [4.0/4.1/4.2/4.3 Regression] placement
 new does not change the dynamic type as it should

On Fri, 8 Jun 2007, ian at airs dot com wrote:

> 
> 
> ------- Comment #171 from ian at airs dot com  2007-06-08 07:49 -------
> Created an attachment (id=13666)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13666&action=view)
>  --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13666&action=view)
> Patch
> 
> This variant of the previous patch does better on at least some of the tramp3d
> functions.  Here we eliminate the CHANGE_DYNAMIC_TYPE_EXPR nodes during the
> first aliasing pass, which prevents them from retaining references to local
> variables and generally clogging up optimizations.

Quick testing shows that this patch indeed shows better performance.
I'll give it complete testing coverage tonight.

Richard.


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