foo i()
...
End foo i

autocmd CursorMovedI *.f90  :call FixName("foo")

" FixName: Change Subprogram name {{{1
function! FixName(arg)
    let [buf, l, c, off] = getpos('.')
    call cursor([1, 1, 0])

    let lnum = search('vc^s*' . a:arg . 's+', 'cnW')
    if !lnum
        call cursor(l, c, off)
        return
    endif

    let parts = matchlist(getline(lnum), 'vc^s*' . a:arg . 's+(S*)s*$')
    if len(parts) < 2
        call cursor(l, c, off)
        return
    endif

    let lnum = search('vc^s*Ends*' . a:arg . 's+', 'cnW')
    call cursor(l, c, off)
    if !lnum
        return
    endif

    call setline(lnum, substitute(getline(lnum), 'vc^s*Ends*' . a:arg . 's+zs.*', parts[1], ''))
endfunction

call setline(lnum, substitute(getline(lnum), 'vc^s*Ends*' . a:arg . 's+zs.*[?=(]', parts[1], ''))