phi.Args = phi.Args[:n]
	phielimValue(phi)
}

// LackingPos indicates whether b is a block whose position should be inherited
// from its successors.  This is true if all the values within it have unreliable positions
// and if it is "plain", meaning that there is no control flow that is also very likely
// to correspond to a well-understood source position.
func (b *Block) LackingPos() bool {

		return m
	}
	return nil
}

// LackingPos indicates whether v is a value that is unlikely to have a correct
// position assigned to it.  Ignoring such values leads to more user-friendly positions
// assigned to nearby values and the blocks containing them.
func (v *Value) LackingPos() bool {
	// The exact definition of LackingPos is somewhat heuristically defined and may change

		s.Fatalf("Block %s should have a position", b)
	}
	bestPos := src.NoXPos
	for _, e := range b.Preds {
		p := e.Block()
		if !p.LackingPos() {
			continue
		}
		if bestPos == src.NoXPos {
			bestPos = b.Pos
			for _, v := range b.Values {
				if v.LackingPos() {
					continue
				}
				if v.Pos != src.NoXPos {
					// Assume values are still in roughly textual order;