; Drive instructions that form a register
proc @foo (i1 %A) -> (i8$ %D) {
entry:
    %delta = const time 0s 1d 0e
    br %A, %final, %active
active:
    %k7i8 = const i8 7
    drv i8$ %D, %k7i8, %delta
    br %final
final:
    wait %entry, %A
}