$ cat > gugu.f

c AtAMul: Left-multiplies matrix AMat by its transpose ----------------
c         AtAMat = transpose(AMat) * AMat
c          k,k               k,n     n,k
c     the resultant matrix AtAMat is returned in lower triangle form
c ---------------------------------------------------------------------
      Subroutine AtAmul(AMat,AtAMat,kDim,nDim)
      IMPLICIT NONE

c   Input:                   Output:                   Local:
      Integer      kDim,nDim,                            i, j, ij, n
      Real*8  AMat(kDim,nDim), AtAMat(kDim*(kDim+1)/2),  Ai1, Ain

c     initialization loop n=1 :
      ij = 0
      do i = 1, kDim
        Ai1 = AMat(i,1)
        do j = 1, i-1
          AtAMat(ij+j) = Ai1 * AMat(j,1)
        enddo
        ij = ij + i
        AtAMat(ij) = Ai1 * Ai1
      enddo

c     accumulation loop n=2,nDim :
      do n = 2, nDim
        ij = 0
        do i = 1, kDim
          Ain = AMat(i,n)
          do j = 1, i-1
            AtAMat(ij+j) = AtAMat(ij+j) + Ain * AMat(j,n)
          enddo
          ij = ij + i
          AtAMat(ij) = AtAMat(ij) + Ain * Ain
        enddo
      enddo

      end
 gfortran -O3 -ftree-loop-linear gugu.f
gugu.f: In function 'atamul_':
gugu.f:6:0: internal compiler error: in initialize_matrix_A, at tree-data-ref.c:1912
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ gfortran-4.4 -O3 -ftree-loop-linear gugu.f
gugu.f: In function 'atamul':
gugu.f:6: internal compiler error: in initialize_matrix_A, at tree-data-ref.c:1880
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-4.4/README.Bugs> for instructions.
$ gfortran-4.3 -O3 -ftree-loop-linear gugu.f
/usr/lib/gcc/i486-linux-gnu/4.3.4/libgfortranbegin.a(fmain.o): In function `main':
(.text+0x35): undefined reference to `MAIN__'
collect2: ld returned 1 exit status