// increases the probability that we will stabilize quickly.
	po := s.f.postorder()
	for {
		changed := false
		for _, b := range po {
			// Start with known live values at the end of the block
			live.clear()
			live.addAll(s.live[b.ID])

			// Propagate backwards to the start of the block
			phis = phis[:0]
			for i := len(b.Values) - 1; i >= 0; i-- {
				v := b.Values[i]
				live.remove(v.ID)
				if v.Op == OpPhi {

	// See issue 18169.
	if hasNilCheck {
		start := -1
		for i, v := range order {
			if v.Op == OpNilCheck {
				if start == -1 {
					start = i
				}
			} else {
				if start != -1 {
					sort.Sort(bySourcePos(order[start:i]))
					start = -1
				}
			}
		}
		if start != -1 {
			sort.Sort(bySourcePos(order[start:]))
		}
	}

	return order
}

			panic("unreachable")
		}
	}

	// Count cycle objects.
	assert(obj.color() >= grey)
	start := obj.color() - grey // index of obj in objPath
	cycle := check.objPath[start:]
	tparCycle := false // if set, the cycle is through a type parameter list
	nval := 0          // number of (constant or variable) values in the cycle; valid if !generic

	out := goEnv("GOGCCFLAGS")
	quote := '\000'
	start := 0
	lastSpace := true
	backslash := false
	s := string(out)
	for i, c := range s {
		if quote == '\000' && unicode.IsSpace(c) {
			if !lastSpace {
				cc = append(cc, s[start:i])
				lastSpace = true
			}
		} else {
			if lastSpace {
				start = i
				lastSpace = false
			}

	for _, op := range operands {
		p.start(op)
		if name, abi, ok := p.funcAddress(); ok {
			fmt.Fprintf(w, "ref %s %s\n", name, abi)
		}
	}
}

func (p *Parser) start(operand []lex.Token) {
	p.input = operand
	p.inputPos = 0
}

// address parses the operand into a link address structure.
func (p *Parser) address(operand []lex.Token) obj.Addr {
	p.start(operand)
	addr := obj.Addr{}

	// type checker will initialize this field with a newly created context.
	Context *Context

	// GoVersion describes the accepted Go language version. The string must
	// start with a prefix of the form "go%d.%d" (e.g. "go1.20", "go1.21rc1", or
	// "go1.21.0") or it must be empty; an empty string disables Go language
	// version checks. If the format is invalid, invoking the type checker will

				}
				b.Values[i] = v
				i++
			}
		}

		if pendingLines.contains(b.Pos) {
			b.Pos = b.Pos.WithIsStmt()
		}

		b.truncateValues(i)

		// TODO: if b.Kind == BlockPlain, start the analysis in the subsequent block to find
		// more unnecessary nil checks.  Would fix test/nilptr3.go:159.
	}

		{name: "LoweredZero", argLength: 2, reg: regInfo{inputs: []regMask{gp}}, aux: "Int64"},                    // large zeroing. arg0=start, arg1=mem, auxint=len, returns mem

		{name: "LoweredGetClosurePtr", reg: gp01},                                                                          // returns wasm.REG_CTXT, the closure pointer

	// unaligned loads and unaligned stores.
	if !f.Config.unalignedOK {
		return
	}

	memcombineLoads(f)
	memcombineStores(f)
}

func memcombineLoads(f *Func) {
	// Find "OR trees" to start with.
	mark := f.newSparseSet(f.NumValues())
	defer f.retSparseSet(mark)
	var order []*Value

	// Mark all values that are the argument of an OR.
	for _, b := range f.Blocks {
		for _, v := range b.Values {

	call := walkGrowslice(s, nif.PtrInit(), oldPtr, newLen, oldCap, num)
	nif.Else = []ir.Node{ir.NewAssignStmt(base.Pos, s, call)}

	nodes.Append(nif)

	// Index to start copying into s.
	//   idx = newLen - len(l2)
	// We use this expression instead of oldLen because it avoids
	// a spill/restore of oldLen.
	// Note: this doesn't work optimally currently because