Changing t=t+j (outher loop variable) to t=t+9 inside two nested for loops increased runtime more than 10%. How this can be possible?

for(int j=-1048576;j<1048576;j+=2000)
  for(int i=-1048576;i<1048576;i++)
    t+=9;//t+=j

CPU:Celeron N3350

I look at assembly of both binaries. Only difference I notice:

t=t+9 :
    addl $9, -4(%rbp)

t=t+j :
    movl -8(%rbp), %eax
    addl %eax, -4(%rbp)