PatternRewriter& rewriter) const {
    bool changed = false;
    rewriter.startOpModification(branch);
    for (auto [call_arg, body_arg] :
         llvm::zip(llvm::drop_begin(ifop.getOperation()->getOperands()),
                   branch.getBody().front().getArguments())) {
      if (call_arg.getType() != body_arg.getType()) {
        body_arg.setType(call_arg.getType());
        changed = true;

    t = TypeMeet(*it, t);
    changed = changed || (t != *it);
    *it++ = t;
  }
  // Now the remaining N from operand types.
  for (auto t : llvm::drop_begin(op->getOperandTypes())) {
    auto meet = TypeMeet(*it, t);
    changed = changed || (meet != *it);
    *it++ = meet;
  }
  if (!changed) return false;