}
			ft.checkpoint()
			// Assume branch p->b is taken.
			addBranchRestrictions(ft, p, pbranch)
			// Check if any outgoing branch is unreachable based on the above condition.
			parent := b
			for j, bbranch := range [...]branch{positive, negative} {
				ft.checkpoint()
				// Try to update relationship b->child, and check if the contradiction occurs.
				addBranchRestrictions(ft, parent, bbranch)
				unsat := ft.unsat
				ft.restore()

		addRestrictions(b, ft, d, iv.ind, iv.max, lt)
	} else {
		addRestrictions(b, ft, d, iv.ind, iv.max, lt|eq)
	}
}

// addBranchRestrictions updates the factsTables ft with the facts learned when
// branching from Block b in direction br.
func addBranchRestrictions(ft *factsTable, b *Block, br branch) {
	c := b.Controls[0]
	switch {
	case br == negative:
		addRestrictions(b, ft, boolean, nil, c, eq)