Enum spirt::ControlNodeKind

pub enum ControlNodeKind {
    Block {
        insts: EntityList<DataInst>,
    },
    Select {
        kind: SelectionKind,
        scrutinee: Value,
        cases: SmallVec<[ControlRegion; 2]>,
    },
    Loop {
        initial_inputs: SmallVec<[Value; 2]>,
        body: ControlRegion,
        repeat_condition: Value,
    },
}

Variants

Block

Fields

insts: EntityList<DataInst>

Linear chain of DataInsts, executing in sequence.

This is only an optimization over keeping DataInsts in ControlRegion linear chains directly, or even merging DataInst with ControlNode.

Select

Fields

kind: SelectionKind

scrutinee: Value

cases: SmallVec<[ControlRegion; 2]>

Choose one ControlRegion out of cases to execute, based on a single value input (scrutinee) interpreted according to SelectionKind.

This corresponds to “gamma” (γ) nodes in (R)VSDG, though those are sometimes limited only to a two-way selection on a boolean condition.

Loop

Fields

initial_inputs: SmallVec<[Value; 2]>

body: ControlRegion

repeat_condition: Value

Execute body repeatedly, until repeat_condition evaluates to false.

To represent “loop state”, body can take inputs, getting values from:

• on the first iteration: initial_inputs
• on later iterations: body’s own outputs (from the last iteration)

As the condition is checked only after the body, this type of loop is sometimes described as “tail-controlled”, and is also equivalent to the C-like do { body; } while(repeat_condition) construct.

This corresponds to “theta” (θ) nodes in (R)VSDG.

Trait Implementations

impl Clone for ControlNodeKind

fn clone(&self) -> ControlNodeKind

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.