Struct GvnTable 

pub struct GvnTable {
    pub table: HashMap<ExprKey, LcnfVarId>,
    pub num_classes: usize,
}

Global Value Numbering (GVN) table.

GVN assigns a value number to every expression; two expressions with the same value number are guaranteed to produce the same result. In our setting the “value number” is simply the canonical LcnfVarId of the first binding that computed the expression.

Fields

table: HashMap<ExprKey, LcnfVarId>

Map from expression key to its canonical representative variable.

num_classes: usize

Number of distinct value numbers assigned.

Implementations

impl GvnTable

pub fn new() -> Self

pub fn lookup(&self, key: &ExprKey) -> Option<LcnfVarId>

Look up the canonical variable for key, if known.

pub fn insert(&mut self, key: ExprKey, var: LcnfVarId) -> LcnfVarId

Register var as the canonical representative for key. If key is already present, the existing representative is kept and var is considered a duplicate.

Trait Implementations

impl Clone for GvnTable

fn clone(&self) -> GvnTable

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GvnTable

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for GvnTable

fn default() -> GvnTable

Returns the “default value” for a type.