// not have any operands other than the predicate, hence we implicitly capture
// the parent token. Also we use the same implicit token for use in the If op's
// regions.
void RewriteRegionIfOp(OpBuilder& builder, IfOp region_if,
                       SmallVectorImpl<OpVisitorState>& ops_to_visit,
                       Value token) {
  llvm::SmallDenseMap<Value, Value> rewritten_operands;