https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78676
janus at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2016-12-05
Ever confirmed|0 |1
--- Comment #5 from janus at gcc dot gnu.org ---
Reduced test case:
program testKISS64
integer, parameter :: Q(2) = [ 393809176, 220190059 ]
integer :: i, z, carry = 415
do i=1,2
z = ishft(ishft(Q(i),9),-1) + &
ishft(ishft(Q(i),7),-1) + &
ishft(carry,-1)
carry = ishft(Q(i),-23) + ishft(Q(i),-25) + ishft(z,-31)
print *, z, carry
end do
end program
gfortran 4.7 and 4.8 print at all optimization levels:
-682598705 58
1741342173 32
That's also what 4.9 prints at -00 and -01. But then 4.9 (and upwards) print at
-O2 and -O3:
-682598705 57
1741342172 32
The error goes away if I remove the loop (even though it occurs already for
i=1).
