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Date: Wed, 03 Jul 2002 22:51:00 -0000
Message-ID: <20020704055150.16219.qmail@sources.redhat.com>
To: gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org,
  wesslen@users.sourceforge.net
From: bkoz@gcc.gnu.org
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  nobody@gcc.gnu.org, wesslen@users.sourceforge.net, gcc-gnats@gcc.gnu.org
Subject: Re: libstdc++/6732: misaligned objects created by new
X-SW-Source: 2002-07/txt/msg00155.txt.bz2
List-Id: <gcc-prs.sourceware.org>

Synopsis: misaligned objects created by new

State-Changed-From-To: open->analyzed
State-Changed-By: bkoz
State-Changed-When: Wed Jul  3 22:51:48 2002
State-Changed-Why:
    I'm not quite convinced that this is a C++ library problem.
    It seems like "C" also has the same issue. 
    
    Note that gcc-2.96, others also have the same behavior.
    
    
    #include <iostream>
     
    struct vec4 
    {
      float x, y, z, w;
    } __attribute__((__aligned__(16)));
    
    int main()
    {
      std::allocator<vec4> a;
      
      for (int i = 0; i < 10; ++i) 
        {
          vec4* p = new vec4;
          std::cerr << reinterpret_cast<void*>(p) << " ";
          std::cerr << reinterpret_cast<std::size_t>(p) % 16 << " ";
          std::cerr << std::endl;
        }
    
      for (int i = 0; i < 10; ++i) 
        {
          vec4* p = reinterpret_cast<vec4*>(malloc(sizeof(vec4)));
          std::cerr << reinterpret_cast<void*>(p) << " ";
          std::cerr << reinterpret_cast<std::size_t>(p) % 16 << " ";
          std::cerr << std::endl;
        }
    }
    

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6732