* worthwhile only if the precomputed matcher is queried many thousands of times.
   *
   * <p>This method has no effect (returns {@code this}) when called in GWT: it's unclear whether a
   * precomputed matcher is faster, but it certainly consumes more memory, which doesn't seem like a
   * worthwhile tradeoff in a browser.
   */
  public CharMatcher precomputed() {

   * worthwhile only if the precomputed matcher is queried many thousands of times.
   *
   * <p>This method has no effect (returns {@code this}) when called in GWT: it's unclear whether a
   * precomputed matcher is faster, but it certainly consumes more memory, which doesn't seem like a
   * worthwhile tradeoff in a browser.
   */
  public CharMatcher precomputed() {

		if len(b.Succs) == 1 {
			if s.f.Config.hasGReg && s.regs[s.GReg].v != nil {
				s.freeReg(s.GReg) // Spill value in G register before any merge.
			}
			// For this to be worthwhile, the loop must have no calls in it.
			top := b.Succs[0].b
			loop := s.loopnest.b2l[top.ID]
			if loop == nil || loop.header != top || loop.containsUnavoidableCall {
				goto badloop
			}