IR TailCall Debug

define dso_local void @caller(double* nocapture %res, double %a) local_unnamed_addr #0 {
entry:
  %call = tail call double @callee(double %a) #2
  store double %call, double* %res, align 8
  ret void
}
define double @callee(double) local_unnamed_addr #1 {
  ret double 4.5
}
attributes #0 = { nounwind }
attributes #1 = { readnone speculatable }
attributes #2 = { nounwind noinline }