g77 -O1 -funroll-loops produces bad code

[Ovidiu Toader <ovi at physics dot utoronto dot ca>]

A user has found that a fortran code which used to work fine 2 months
ago now gets a SIGSEGV when compiled with -O1 -funroll-loops. The egcs
tree is kept almost in sync with the latest snapshots. 

I've trimmed down the code as much as possible. At this point the
SIGSEGV is received in a different location than the original SIGSEGV.

The declarations are from the original code and ALL of them are needed 
to trigger the bug!! 
 
-- 
        Ovidiu

toucan:~/work/f77> uname -a
Linux toucan.physics.utoronto.ca 2.0.36 #3 Sat Jan 9 19:07:50 EST 1999
i686 unknown
toucan:~/work/f77> g77 -v
g77 version egcs-2.93.09 19990221 (gcc2 ss-980929 experimental) (from
FSF-g77 version 0.5.24-19990219)
...........................................................
toucan:~/work/f77> cat bug.f
c     g77 -O1 -funroll-loops 
c     These declarations are needed to trigger the bug!!!!!!
      implicit none
      INTEGER Ncell, N,  LWORK, Nsites, Nhole, Nele, Nsvd
      DOUBLE PRECISION u, S, errmax,  eta
      parameter(Ncell=20 ,Nsites=2*Ncell, N=2*Nsites,LWORK=3*N-1)
      parameter(u=8.d0, S=0.5d0, errmax=1.d-6)
      parameter(Nhole=1, Nele=Nsites-Nhole)
      parameter(eta=0.d0)
      parameter(Nsvd=4*Nsites)
      integer LDA, INFO,  i, j, kp, kh, k, num
      integer  kp2, kh2, i1
      integer  crit
      character JOBZ, UPLO, BOUNDARY
      logical flag
      DOUBLE PRECISION Spinx(Nsites), Spinz(Nsites), Dens(Nsites)
      DOUBLE PRECISION A(N,N), W(N), WORK(LWORK), val
      double precision ca, sav, delta
      DOUBLE PRECISION wo, csihp
      complex*16  M(Nsvd, Nsvd), ima, dw1, dw2,cond,condo
      complex*16 csi(Nsvd), bi(Nsvd), D
      CHARACTER JOBU, JOBVT
      INTEGER LWORK1
      parameter( LWORK1=4*Nsvd)
      DOUBLE PRECISION RWORK(5*Nsvd-4), Sing(Nsvd)
      COMPLEX*16 Uma(Nsvd,Nsvd),VT(Nsvd,Nsvd),WORK1(LWORK1)

      do i=1,Nsites
         Spinx(i) = i
         Spinz(i) = i
         Dens(i) = i
      enddo

      do i=1,N
         do j=1,N
            A(i,j)=1.d0
         enddo
      enddo   

      end
toucan:~/work/f77> g77 -O1 bug.f -o exe
toucan:~/work/f77> exe
toucan:~/work/f77> g77 -O1 -funroll-loops bug.f -o exe
toucan:~/work/f77> exe
Segmentation fault