19981122 optimization bug

[Helmut Jarausch <jarausch at IGPM dot Rwth-Aachen dot DE>]

Hello,

with this current version I encounter a strange optimization bug.
Unfortunately the full header file is quite long (150 Kb, might be cut down
to one half)

1st) there were no problems with previous versions
2nd) the bug does not occur if not compiled with  -fstrict-aliasing
3rd) the bug does not occur if the statement
     // cerr << hex << Q.raw() << endl; // OK if uncommented
     is uncommented

How can I help to isolate the bug?

Code  when ompiled with  -O3 -fstrict-aliasing

#define MAT_VEC_REAL
#define MAT_VEC_COMPLEX

#include "IGPMatrix"

    using IGPMatrix::cMatrix;
    using IGPMatrix::cMatrix_R;
    using IGPMatrix::MatVecMMC;
    using IGPMatrix::Complex;
#ifndef __sgi
    using IGPMatrix::drand48;
#endif

#define  crand48()  Complex(drand48(),drand48())


void Init_cMatrix( cMatrix& A )
{ for ( int k= A.cols(); k > 0; k-- )
  for ( int i= A.rows(); i > 0; i-- ) A(i,k)= crand48();
}

int  Mchk = 0;


void check( cMatrix_R R, const char Msg[] )
{ double err;
  cout << "*** Matrix-Check " << ++Mchk << endl << flush;
  if ( (err= norm(R)) > 1E-12 )
  { cout << "\n Check " << Msg << " failed err= " <<err
         << flush; abort();
  }
}

const int Rows=13, Cols=7;


// void ccheck8( const cMatrix& Q, const cMatrix& R );

void ccheck8( const cMatrix& Q, const cMatrix& R )
{
  check(Q+R-Q-R,"mat +-");
// cerr << hex << Q.raw() << endl; // OK if uncommented
  check(Q*2-1*Q-Q,"M*d-");
}

main()
{ 
  cMatrix Q(Rows,Cols), R(Rows,Cols);

  Init_cMatrix(Q);  Init_cMatrix(R);
  ccheck8( Q, R );  // fails
  return 0;
}


Many thanks for looking into it,





--
Helmut Jarausch
Lehrstuhl fuer Numerische Mathematik
Institute of Technology, RWTH Aachen
D 52056 Aachen, Germany