SymbolTable &to) {
  if (to.lookup<func::FuncOp>(symbol_ref.getValue())) return;
  func::FuncOp callee = from.lookup<func::FuncOp>(symbol_ref.getValue());
  callee.getOperation()->getBlock()->getOperations().remove(
      callee.getOperation());
  to.insert(callee);
}

void TPUBridgeExecutorIslandOutlining::runOnOperation() {
  MLIRContext *ctx = &getContext();

// CallExpr beneath an ExprStmt.
func New(body *ast.BlockStmt, mayReturn func(*ast.CallExpr) bool) *CFG {
	b := builder{
		mayReturn: mayReturn,
		cfg:       new(CFG),
	}
	b.current = b.newBlock(KindBody, body)
	b.stmt(body)

	// Compute liveness (reachability from entry point), breadth-first.
	q := make([]*Block, 0, len(b.cfg.Blocks))
	q = append(q, b.cfg.Blocks[0]) // entry point
	for len(q) > 0 {