// first

    for x in f.Body.Instructions do
        // Copy to branches
        match x.OpCode.OperandType with
        | OperandType.InlineBrTarget
        | OperandType.ShortInlineBrTarget ->
            let y = x.Operand :?> Instruction
            depths.[y] <- depth
        | OperandType.InlineSwitch ->
            for y in x.Operand :?> Instruction array do
                depths.[y] <- depth
        | _ ->
            ()

        // Empty after unconditional control transfer unless forward branch
        match x.OpCode.FlowControl with
        | FlowControl.Branch
        | FlowControl.Break
        | FlowControl.Return
        | FlowControl.Throw ->
            depth <- 0
        | _ ->
            ()
    depths

// second

    for x in f.Body.Instructions do

        // Copy to branches
        match x.OpCode.OperandType with
        | OperandType.InlineBrTarget
        | OperandType.ShortInlineBrTarget ->
            let y = x.Operand :?> Instruction
            depths.[y] <- depth
        | OperandType.InlineSwitch ->
            for y in x.Operand :?> Instruction array do
                depths.[y] <- depth
        | _ ->
            ()

        // Empty after unconditional control transfer unless forward branch
        match x.OpCode.FlowControl with
        | FlowControl.Branch
        | FlowControl.Break
        | FlowControl.Return
        | FlowControl.Throw ->
            depth <- 0
        | _ ->
            ()

    depths