Lower ion to rtio

[rniczh]

Context:

Convert ion dialect to rtio dialect

Description of the Change:

There are several steps to convert the ion dialect to rtio dialect:

0. Prepare the enviorment:

   • Import device db json to rtio.config
   • Collect ION infos
   • Create a kernel function, which is just cloned from the original qnode function
   • Drop the pulse with transition 0, that's because that can't be applied on the current device, and it will be dropped in the current ARTIQ's compilation flow as well
   • Initialize memref map: Construct mapping from qreg alloc and qreg extract to memref. In the later conversion, we use the mapping to construct the channel for rtio.pulse. It will create a global memref that contains index from 0 to N to represent the qubits.

1. parallel protocol to rtio:
   Converts ion.parallelprotocol regions into flat RTIO operations with proper synchronization. We rely on the data dependency of qubit to introduce the unrealized conversion cast between ion.qubit and rtio.event. That's the way how we currently build the relationship between events. Later, those unrealized conversion cast will be removed via event propagation.

   Input mlir:

    %0, %1 = ion.parallelprotocol(%q0, %q1) {
      ^bb0(%arg0, %arg1):
      %p0 = rtio.pulse(...) : !rtio.event
      %p1 = rtio.pulse(...) : !rtio.event
      ion.yield %arg0, %arg1
    }

    %event0 = unrealized_conversion_cast %q0 : !ion.qubit -> !rtio.event
    %event1 = unrealized_conversion_cast %q1 : !ion.qubit -> !rtio.event
    %p0 = rtio.pulse(..., wait = %inputSync) : !rtio.event
    %p1 = rtio.pulse(..., wait = %inputSync) : !rtio.event
    %sync = rtio.sync %p0, %p1 : !rtio.event
    %0 = unrealized_conversion_cast %sync : !rtio.event -> !ion.qubit
    %1 = unrealized_conversion_cast %sync : !rtio.event -> !ion.qubit

2. ion.pulse to rtio.pulse:
   Converts ion.pulse to rtio.pulse with calculated frequency.

   Frequency Calculation:

   frequency = (reference_energy + detuning - raman1_frequency) / (2 * pi)

   Steps:

   • Extract pulse parameters (duration, beam, phase)
   • Calculate frequency from transition index and detuning
   • Create rtio.channel via rtio.qubit_to_channel
   • Generate rtio.pulse operation

3. Resolve channel mapping
   Resolves dynamic channel references to static channel IDs.

   memref.global (constants) -> memref.get_global -> memref.load -> qubit_to_channel
   

   // Before
   %ch = rtio.qubit_to_channel %qubit : !ion.qubit -> !rtio.channel<"dds", ?>
   
   // After
   %ch = rtio.channel "dds" { channel_id = N } : !rtio.channel<"dds">

4. propagate events
   Resolves unrealized_conversion_cast and connect the ops with event type

   Steps:

   • Trace backward to collect all the source events.
   • Create sync from collected events
   • If reaches quantum.AllocOp: create rtio.empty

5. Remove all other dialects:
   Removes unused quantum/ion/memref/linalg dialect after conversion.

TODOs:

• Add lit tests

Benefits:

Possible Drawbacks:

Related GitHub Issues:
[sc-100851]