You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: deadstore.go
    path of file: ./repos/under-the-hood/gosrc/cmd/compile/internal/ssa
    
    the code of the file until where you have to start completion: // Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package ssa

import (
	"cmd/compile/internal/types"
	"cmd/internal/src"
)

// 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) {
	var stores []*Value
	loadUse := f.newSparseSet(f.NumValues())
	defer f.retSparseSet(loadUse)
	storeUse := f.newSparseSet(f.NumValues())
	defer f.retSparseSet(storeUse)
	shadowed := f.newSparseMap(f.NumValues())
	defer f.retSparseMap(shadowed)
	for _, b := range f.Blocks {
		// Find all the stores in this block. Categorize their uses:
		//  loadUse contains stores which are used by a subsequent load.
		//  storeUse contains stores which are used by a subsequent store.
		loadUse.clear()
		storeUse.clear()
		stores = stores[:0]
		for _, v := range b.Values {
			if v.Op == OpPhi {
				// Ignore phis - they will always be first and can't be eliminated
				continue
			}
			if v.Type.IsMemory() {
				stores = append(stores, v)
				for _, a := range v.Args {
					if a.Block == b && a.Type.IsMemory() {
						storeUse.add(a.ID)
						if v.Op != OpStore && v.Op != OpZero && v.Op != OpVarDef && v.Op != OpVarKill {
							// CALL, DUFFCOPY, etc. are both
							// reads and writes.
							loadUse.add(a.ID)
						}
					}
				}
			} else {
				for _, a := range v.Args {
					if a.Block == b && a.Type.IsMemory() {
						loadUse.add(a.ID)
					}
				}
			}
		}
		if len(stores) == 0 {
			continue
		}

		// find last store in the block
		var last *Value
		for _, v := range stores {
			if storeUse.contains(v.ID) {
				continue
			}
			if last != nil {
				b.Fatalf("two final stores - simultaneous live stores %s %s", last.LongString(), v.LongString())
			}
			last = v
		}
		if last == nil {
			b.Fatalf("no last store found - cycle?")
		}

		// Walk backwards looking for dead stores. Keep track of shadowed addresses.
		// An "address" is an SSA Value which encodes both the address and size of
		// the write. This code will not remove dead stores to the same address
		// of different types.
		shadowed.clear()
		v := last

	walkloop:
		if loadUse.contains(v.ID) {
			// Someone might be reading this memory state.
			// Clear all shadowed addresses.
			shadowed.clear()
		}
		if v.Op == OpStore || v.Op == OpZero {
			var sz int64
			if v.Op == OpStore {
				sz = v.Aux.(*types.
    
func dse(f *Func) {
	var stores []*Value
	loadUse := f.newSparseSet(f.NumValues())
	defer f.retSparseSet(loadUse)
	storeUse := f.newSparseSet(f.NumValues())
	defer f.retSparseSet(storeUse)
	shadowed := f.newSparseMap(f.NumValues())
	defer f.retSparseMap(shadowed)
	for _, b := range f.Blocks {
		// Find all the stores in this block. Categorize their uses:
		//  loadUse contains stores which are used by a subsequent load.
		//  storeUse contains stores which are used by a subsequent store.
		loadUse.clear()
		storeUse.clear()
		stores = stores[:0]
		for _, v := range b.Values {
			if v.Op == OpPhi {
				// Ignore phis - they will always be first and can't be eliminated
				continue
			}
			if v.Type.IsMemory() {
				stores = append(stores, v)
				for _, a := range v.Args {
					if a.Block == b && a.Type.IsMemory() {
						storeUse.add(a.ID)
						if v.Op != OpStore && v.Op != OpZero && v.Op != OpVarDef && v.Op != OpVarKill {
							// CALL, DUFFCOPY, etc. are both
							// reads and writes.
							loadUse.add(a.ID)
						}
					}
				}
			} else {
				for _, a := range v.Args {
					if a.Block == b && a.Type.IsMemory() {
						loadUse.add(a.ID)
					}
				}
			}
		}
		if len(stores) == 0 {
			continue
		}

		// find last store in the block
		var last *Value
		for _, v := range stores {
			if storeUse.contains(v.ID) {
				continue
			}
			if last != nil {
				b.Fatalf("two final stores - simultaneous live stores %s %s", last.LongString(), v.LongString())
			}
			last = v
		}
		if last == nil {
			b.Fatalf("no last store found - cycle?")
		}

		// Walk backwards looking for dead stores. Keep track of shadowed addresses.
		// An "address" is an SSA Value which encodes both the address and size of
		// the write. This code will not remove dead stores to the same address
		// of different types.
		shadowed.clear()
		v := last

	walkloop:
		if loadUse.contains(v.ID) {
			// Someone might be reading this memory state.
			// Clear all shadowed addresses.
			shadowed.clear()
		}
		if v.Op == OpStore || v.Op == OpZero {
			var sz int64
			if v.Op == OpStore {
				sz = v.Aux.(*types.Type).Size()
			} else { // OpZero
				sz = v.AuxInt
			}
			if shadowedSize := int64(shadowed.get(v.Args[0].ID)); shadowedSize != -1 && shadowedSize >= sz {
				// Modify store into a copy
				if v.Op == OpStore {
					// store addr value mem
					v.SetArgs1(v.Args[2])
				} else {
					// zero addr mem
					typesz := v.Args[0].Type.Elem().Size()
					if sz != typesz {
						f.Fatalf("mismatched zero/store sizes: %d and %d [%s]",
							sz, typesz, v.LongString())
					}
					v.SetArgs1(v.Args[1])
				}
				v.Aux = nil
				v.AuxInt = 0
				v.Op = OpCopy
			} else {
				if sz > 0x7fffffff { // work around sparseMap's int32 value type
					sz = 0x7fffffff
				}
				shadowed.set(v.Args[0].ID, int32(sz), src.NoXPos)
			}
		}
		// walk to previous store
		if v.Op == OpPhi {
			// At start of block.  Move on to next block.
			// The memory phi, if it exists, is always
			// the first logical store in the block.
			// (Even if it isn't the first in the current b.Values order.)
			continue
		}
		for _, a := range v.Args {
			if a.Block == b && a.Type.IsMemory() {
				v = a
				goto walkloop
			}
		}
	}
}