16bit atomic loads missing (LDRHHroX)

[LadnerJonas]

At Lingodb, we would like to ditch our tpde fork and instead use your upstream repository. The only instruction, that we use but is missing here, is LDRHHroX.

Our current hacky fix is:

// tpde-encodegen/src/arm64/Target.cpp Line 370
  if (Name == "LDRHHroX") {
    unsigned extension = mi.getOperand(3).getImm();
    unsigned sc = mi.getOperand(4).getImm();
    std::array<std::string, 4> mnemSuffix{"lsl", "uxtw", "sxtw", "sxtx"};
    if (extension != 0) {
      assert(0 && "check if the emitted code really uses this suffix (godbolt using the same compilation arguments)");
    }
    handle_noimm("LDRHr_" + mnemSuffix[extension], std::format(", {}", sc));
  }

As you probably notice, we only handle extension case = 0, so the remaining mnemSuffix should be double-checked for correctness. After this instruction is added, I think we can stop using our fork and directly use the upstream repository.

Thanks!