po.flags &^= posetFlagUnsigned
	}
}

// Handle children
func (po *poset) setchl(i uint32, l posetEdge) { po.nodes[i].l = l }
func (po *poset) setchr(i uint32, r posetEdge) { po.nodes[i].r = r }
func (po *poset) chl(i uint32) uint32          { return po.nodes[i].l.Target() }
func (po *poset) chr(i uint32) uint32          { return po.nodes[i].r.Target() }
func (po *poset) children(i uint32) (posetEdge, posetEdge) {

}

// assembleChildren initializes the children field of each
// loop in the nest.  Loop A is a child of loop B if A is
// directly nested within B (based on the reducible-loops
// detection above)
func (ln *loopnest) assembleChildren() {
	if ln.initializedChildren {
		return
	}
	for _, l := range ln.loops {
		if l.outer != nil {
			l.outer.children = append(l.outer.children, l)
		}
	}

//		if ... should visit children ... {
//			ir.DoChildren(x, do)
//			... processing AFTER visiting children ...
//		}
//		if ... should stop parent DoChildren call from visiting siblings ... {
//			return true
//		}
//		return false
//	}
//	do(root)
//
// Since DoChildren does not return true itself, if the do function
// never wants to stop the traversal, it can assume that DoChildren

			err(obj, alt)
		}
	}

	j := -1 // index of s in p.children
	for i, ch := range p.children {
		if ch == s {
			j = i
			break
		}
	}
	assert(j >= 0)
	k := len(p.children) - 1
	p.children[j] = p.children[k]
	p.children = p.children[:k]

	p.children = append(p.children, s.children...)

	s.children = nil
	s.elems = nil
}

	}
	t.numberBlock(f.Entry, 1)
	return t
}

// newSparseOrderedTree creates a SparseTree from a block-to-parent map (array indexed by Block.ID)
// children will appear in the reverse of their order in reverseOrder
// in particular, if reverseOrder is a dfs-reversePostOrder, then the root-to-children
// walk of the tree will yield a pre-order.
func newSparseOrderedTree(f *Func, parentOf, reverseOrder []*Block) SparseTree {

	callIdx = len(dwcalls.Calls) - 1
	imap[inlIdx] = callIdx

	if parCallIdx != -1 {
		// Add this inline to parent's child list
		dwcalls.Calls[parCallIdx].Children = append(dwcalls.Calls[parCallIdx].Children, callIdx)
	}

	return callIdx
}

// Given a src.XPos, return its associated inlining index if it
// corresponds to something created as a result of an inline, or -1 if

}

type node struct {
	actualFilePath string           // empty if a directory
	children       map[string]*node // path element → file or directory
}

func (n *node) isDir() bool {
	return n.actualFilePath == "" && n.children != nil
}

func (n *node) isDeleted() bool {
	return n.actualFilePath == "" && n.children == nil
}

// TODO(matloob): encapsulate these in an io/fs-like interface

	sibling    ID    // next child of parent
	pos        int32 // an index in the Euler tour where this block appears (any one of its occurrences)
	depth      int32 // depth in dominator tree (root=0, its children=1, etc.)
}

func makeLCArange(f *Func) *lcaRange {
	dom := f.Idom()

	// Build tree
	blocks := make([]lcaRangeBlock, f.NumBlocks())
	for _, b := range f.Blocks {
		blocks[b.ID].b = b

package syntax

import "fmt"

// Inspect traverses an AST in pre-order: it starts by calling f(root);
// root must not be nil. If f returns true, Inspect invokes f recursively
// for each of the non-nil children of root, followed by a call of f(nil).
//
// See Walk for caveats about shared nodes.
func Inspect(root Node, f func(Node) bool) {
	Walk(root, inspector(f))
}

type inspector func(Node) bool

	// properties of the dominator tree
	idom  []*ssa.Block // dominator parents
	tree  []domBlock   // dominator child+sibling
	level []int32      // level in dominator tree (0 = root or unreachable, 1 = children of root, ...)

	// scratch locations
	priq   blockHeap    // priority queue of blocks, higher level (toward leaves) = higher priority
	q      []*ssa.Block // inner loop queue
	queued *sparseSet   // has been put in q