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[Bug libstdc++/29286] [4.0/4.1/4.2/4.3 Regression] placement new does not change the dynamic type as it should
- From: "rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 8 Jun 2007 13:47:08 -0000
- Subject: [Bug libstdc++/29286] [4.0/4.1/4.2/4.3 Regression] placement new does not change the dynamic type as it should
- References: <bug-29286-10053@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- 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.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29286