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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



------- Comment #159 from ian at airs dot com  2007-05-25 23:21 -------
Created an attachment (id=13613)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13613&action=view)
Patch

This version of the patch is based on some code from Daniel Berlin.  Here we
determine which pointers can potentially be associated with a placement new. 
We disable TBAA specifically for those pointers.

I'm not 100% confident that this patch always does the right thing.  But it
does work for the test cases I tried.

Richi, I'd be interested in results you get from your performance tests.


-- 

ian at airs dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #13553|0                           |1
        is obsolete|                            |


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


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