// license that can be found in the LICENSE file.

package ssa

// This file contains code to compute the dominator tree
// of a control-flow graph.

// postorder computes a postorder traversal ordering for the
// basic blocks in f. Unreachable blocks will not appear.
func postorder(f *Func) []*Block {
	return postorderWithNumbering(f, nil)
}

type blockAndIndex struct {
	b     *Block

			continue
		}
		m := module.Version{Path: path, Version: max[path]}
		min = append(min, m)
		walk(m)
		haveBase[path] = true
	}
	// Now the reverse postorder to bring in anything else.
	for i := len(postorder) - 1; i >= 0; i-- {
		m := postorder[i]
		if max[m.Path] != m.Version {
			// Older version.
			continue
		}
		if !have[m] {
			min = append(min, m)
			walk(m)
		}
	}

//  1 type filtering
//  2 pruning
//  3 postorder calls to f
//  4 stack
// Rather than offer all of them in the API,
// only a few combinations are exposed:
// - Preorder is the fastest and has fewest features,
//   but is the most commonly needed traversal.
// - Nodes and WithStack both provide pruning and postorder calls,
//   even though few clients need it, because supporting two versions

// Comment assignment.
// We build two lists of all subexpressions, preorder and postorder.
// The preorder list is ordered by start location, with outer expressions first.
// The postorder list is ordered by end location, with outer expressions last.
// We use the preorder list to assign each whole-line comment to the syntax
// immediately following it, and we use the postorder list to assign each
// end-of-line comment to the syntax immediately preceding it.

	}
	f.fe.Fatalf(f.Entry.Pos, msg, args...)
}

// postorder returns the reachable blocks in f in a postorder traversal.
func (f *Func) postorder() []*Block {
	if f.cachedPostorder == nil {
		f.cachedPostorder = postorder(f)
	}
	return f.cachedPostorder
}

func (f *Func) Postorder() []*Block {
	return f.postorder()
}

	defer f.Cache.freeInt8Slice(certain)
	local := f.Cache.allocInt8Slice(f.NumBlocks()) // for our immediate predecessors.
	defer f.Cache.freeInt8Slice(local)

	po := f.postorder()
	nest := f.loopnest()
	b2l := nest.b2l

	for _, b := range po {
		switch b.Kind {
		case BlockExit:
			// Very unlikely.
			local[b.ID] = blEXIT
			certain[b.ID] = blEXIT

 *
 * <pre>{@code
 *        h
 *      / | \
 *     /  e  \
 *    d       g
 *   /|\      |
 *  / | \     f
 * a  b  c
 * }</pre>
 *
 * <p>can be iterated over in preorder (hdabcegf), postorder (abcdefgh), or breadth-first order
 * (hdegabcf).
 *
 * <p>Null nodes are strictly forbidden.
 *
 * <p>Because this is an abstract class, not an interface, you can't use a lambda expression to
 * implement it:
 *

	// each block. This is basically a best-effort live variable
	// analysis, so it can be much simpler than a full analysis.
	end := f.Cache.allocValueSlice(f.NumBlocks())
	defer f.Cache.freeValueSlice(end)
	po := f.postorder()
	for n := 0; n < 2; n++ {
		for _, b := range po {
			// Walk values backwards to figure out what flag
			// value we want in the flag register at the start
			// of the block.
			var flag *Value

// -d=ssa/number_lines/stats=1 (that bit) for line and file distribution statistics
// -d=ssa/number_lines/debug for information about why particular values are marked as statements.
func numberLines(f *Func) {
	po := f.Postorder()
	endlines := make(map[ID]src.XPos)
	ranges := make(map[int]lineRange)
	note := func(p src.XPos) {
		line := uint32(p.Line())
		i := int(p.FileIndex())
		lp, found := ranges[i]
		change := false

 *
 * <pre>{@code
 *        h
 *      / | \
 *     /  e  \
 *    d       g
 *   /|\      |
 *  / | \     f
 * a  b  c
 * }</pre>
 *
 * <p>can be iterated over in preorder (hdabcegf), postorder (abcdefgh), or breadth-first order
 * (hdegabcf).
 *
 * <p>Null nodes are strictly forbidden.
 *
 * <p>Because this is an abstract class, not an interface, you can't use a lambda expression to
 * implement it:
 *