go/src/cmd/compile/internal/ssa/deadstore.go

// dse does dead-store elimination on the Function.
// Dead stores are those which are unconditionally followed by
// another store to the same location, with no intervening load.
// This implementation only works within a basic block. TODO: use something more global.
func dse(f *Func) { … }

type shadowRange …

func (sr shadowRange) lo() int64 { … }

func (sr shadowRange) hi() int64 { … }

// contains reports whether [lo:hi] is completely within sr.
func (sr shadowRange) contains(lo, hi int64) bool { … }

// merge returns the union of sr and [lo:hi].
// merge is allowed to return something smaller than the union.
func (sr shadowRange) merge(lo, hi int64) shadowRange { … }

// elimDeadAutosGeneric deletes autos that are never accessed. To achieve this
// we track the operations that the address of each auto reaches and if it only
// reaches stores then we delete all the stores. The other operations will then
// be eliminated by the dead code elimination pass.
func elimDeadAutosGeneric(f *Func) { … }

// elimUnreadAutos deletes stores (and associated bookkeeping ops VarDef and VarKill)
// to autos that are never read from.
func elimUnreadAutos(f *Func) { … }