Class ParallelMoves

src/internal/parallel_moves.rs:528–555

Resolver which turns a set of parallel move operations into a linear sequence of move operations. This is also responsible for inserting the necessary scratch registers for things like stack-to-stack moves and rematerialization into a stack slot.

/// This is also responsible for inserting the necessary scratch registers for
/// things like stack-to-stack moves and rematerialization into a stack slot.
pub struct ParallelMoves {
    /// Final list of moves generated by the parallel move resolver.
    ///
    /// The edits are stored in *reverse order* due to the way we generate them.
    edits: Vec<Edit>,

    /// Set of parallel move operations that need to be resolved.
    moves: PrimaryMap<MoveIndex, Move>,

    /// List of values that will be re-materialized separately after all moves
    /// have been performed.
    remat: Vec<(Value, RegClass, Allocation)>,

    /// Same as `remat` but for rematerializations where an intermediate scratch
    /// register is needed.
    remat_with_scratch: Vec<(Value, RegClass, Allocation)>,

    /// For each allocation unit that is written to by a move, this holds the
    /// index of the move writing to it.
    writes_to_unit: SparseMap<AllocationUnit, MoveIndex>,

    /// Allocator for scratch registers that may be needed to resolve cycles and
    /// memory-to-memory moves.
    scratch: ScratchAllocator,

    /// Stack for DFS.
    stack: Vec<(Visit, MoveIndex)>,
}

impl Default for ParallelMoves {
    fn default() -> Self {