[Bug c++/11091] Wrong code in variable initialization

["dej at inode dot org" <gcc-bugzilla at gcc dot gnu dot org>]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11091



------- Additional Comments From dej@inode.org  2003-06-05 02:53 -------
My observations are taken with no optimization.  Sample compile  
line:  
  
/usr/local/gcc322/bin/gcc -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\"  
-DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"xeda\"  
-DVERSION=\"0.1\"  -I. -I. -I.. -I../util/ -I../../boost/    -g -c -o DBElabNet.o `test  
-f DBElabNet.cpp || echo './'`DBElabNet.cpp  
  
I would have loved to submit a smaller example.  Trivial test cases work properly: the  
smart pointer is initialized to zero.  It is only this large case that fails (and perhaps 
only in this method; I have not investigated other declarations to see if the problem 
occurs multiple times).  
  
As far as the code goes, I still believe it is wrong:  
  
     86b:       83 ec 40                sub    $0x40,%esp  
     86e:       8b 5d 14                mov    0x14(%ebp),%ebx  
     871:       8b 45 08                mov    0x8(%ebp),%eax  
     874:       89 04 24                mov    %eax,(%esp,1)  
     877:       e8 fc ff ff ff          call   878  
<_ZNK14DBInstantiator9findChildE5GCPtrI6DBNameE9DBObjType+0x12>  
  
The variable is stored on the stack, not in a register.  At least that's what GDB tells  
me when I print &obj.  For the code above, obj is located in the stack frame at offset  
0x8(%ebp).  It is the CONTENTS of this location that is pushed onto the stack and which  
forms the argument to the constructor.  Said contents are of course uninitialized.  
  
If the mov at line 871 were replaced with lea, then the code would work correctly. I 
actually see lea used in code sequence in a different function in the same file in my 
working sources. 
 
Am I missing something here?  If you want, give me your phone number and I can call you 
tomorrow to discuss this further. 
 
  



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