import "cmd/compile/internal/base"

// tighten moves Values closer to the Blocks in which they are used.
// This can reduce the amount of register spilling required,
// if it doesn't also create more live values.
// A Value can be moved to any block that
// dominates all blocks in which it is used.
func tighten(f *Func) {
	if base.Flag.N != 0 && len(f.Blocks) < 10000 {
		// Skip the optimization in -N mode, except for huge functions.

			v := b.Values[i]
			if opcodeTable[v.Op].argLen == 0 {
				key := vkey{v.Op, keyFor(v), v.Aux, v.Type}
				if vals[key] == nil {
					vals[key] = v
					if b != f.Entry {
						// Move v to the entry block so it will dominate every block
						// where we might use it. This prevents the need for any dominator
						// calculations in this pass.
						v.Block = f.Entry

// return function type, receiver as first argument (or not).
func NewMethodType(sig *types.Type, recv *types.Type) *types.Type {
	nrecvs := 0
	if recv != nil {
		nrecvs++
	}

	// TODO(mdempsky): Move this function to types.
	// TODO(mdempsky): Preserve positions, names, and package from sig+recv.

	params := make([]*types.Field, nrecvs+sig.NumParams())
	if recv != nil {

	ANOALG         // implies ANOEQ, and in addition has a part that is marked Noalg
	AMEM           // Type can be compared/hashed as regular memory.
	AMEM0          // Specific subvariants of AMEM (TODO: move to ../reflectdata?)
	AMEM8
	AMEM16
	AMEM32
	AMEM64
	AMEM128
	ASTRING
	AINTER
	ANILINTER
	AFLOAT32
	AFLOAT64
	ACPLX64
	ACPLX128
	ASPECIAL // Type needs special comparison/hashing functions.
)

// An xposmap is a map from fileindex and line of src.XPos to int32,
// implemented sparsely to save space (column and statement status are ignored).
// The sparse skeleton is constructed once, and then reused by ssa phases
// that (re)move values with statements attached.
type xposmap struct {
	// A map from file index to maps from line range to integers (block numbers)
	maps map[int32]*biasedSparseMap

	// Parameter value feeds unmodified into a top level "switch"
	// statement or "if" statement simple expressions (see more on
	// "simple" expression classification below).
	ParamFeedsIfOrSwitch

	// Parameter value feeds unmodified into a "switch" or "if"
	// statement simple expressions (see more on "simple" expression
	// classification below), where the if/switch is
	// conditional/nested.
	ParamMayFeedIfOrSwitch
)

		}

		switch n {
		// Handle very small clears with move instructions.
		case 8, 4, 2, 1:
			ins := s390x.AMOVB
			switch n {
			case 8:
				ins = s390x.AMOVD
			case 4:
				ins = s390x.AMOVW
			case 2:
				ins = s390x.AMOVH
			}
			p = pp.Append(p, ins, obj.TYPE_CONST, 0, 0, obj.TYPE_MEM, reg, off)

		// Handle clears that would require multiple move instructions with CLEAR (assembled as XC).
		default:

	for i, b := range f.Blocks {
		idToIdx[b.ID] = i
	}

	// Set of blocks we're moving, by ID.
	move := map[ID]struct{}{}

	// Map from block ID to the moving blocks that should
	// come right after it.
	after := map[ID][]*Block{}

	// Check each loop header and decide if we want to move it.
	for _, loop := range loopnest.loops {
		b := loop.header
		var p *Block // b's in-loop predecessor

			break
		} // no other incoming edge
		c = cNext
	}

	// Try to preserve any statement marks on the ends of blocks; move values to C
	var b_next *Block
	for bx := b; bx != c; bx = b_next {
		// For each bx with an end-of-block statement marker,
		// try to move it to a value in the next block,
		// or to the next block's end, if possible.
		b_next = bx.Succs[0].b
		if bx.Pos.IsStmt() == src.PosIsStmt {

		goto redo
	}
}

// fill reads more source bytes into s.buf.
// It returns with at least one more byte in the buffer, or with s.ioerr != nil.
func (s *source) fill() {
	// determine content to preserve
	b := s.r
	if s.b >= 0 {
		b = s.b
		s.b = 0 // after buffer has grown or content has been moved down
	}
	content := s.buf[b:s.e]

	// grow buffer or move content down
	if len(content)*2 > len(s.buf) {