[Bug tree-optimization/34048] [4.3 Regression]: Revision 130040 miscompiles 450.soplex

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

------- Comment #6 from rguenth at gcc dot gnu dot org  2007-11-10 16:42 -------
This looks like a bug in soplex.  It does:

class UnitVector : public SVector
{
private:
   Element themem;
   Element themem1; 

public:

...
   UnitVector(int i = 0)
      : SVector(2, &themem)
   {  
      add(i, 1.0);
   }

and:

class SVector
{
...
   struct Element
   {  
      Real val;
      int idx;
   };
   Element *m_elem;
...
   SVector(int n = 0, Element* p_mem = 0)
   {  
      setMem(n, p_mem);
   }
...
   void setMem(int n, Element* elmem)
   {  
      (static_cast<void> (0));

      if (n > 0)
      {
         (static_cast<void> (0));
         elmem->val = 0;
         m_elem = &(elmem[1]);
         set_size( 0 );
         set_max ( n - 1 );
      }
      else
         m_elem = 0;
   }

that is, SVector accesses themem, themem1 as array (obviously to avoid
unneccessary default construction).  If you fix this, the miscompile
goes away.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34048