🚧 A compiler native Decomposition Graph Solver in C++ #2065
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…r e2e testing from v3)
… present in MLIR (#2001) **Context:** Introduces a new MLIR pass that enables user-defined decomposition of quantum gate operations. The pass discovers decomposition functions in the module and uses MLIR's inlining infrastructure to replace target quantum operations with their decomposed implementations. **Description of the Change:** This PR will **recognize** the `func.func` as decomposition if they have name start with the pattern `<Gate>_rule[.]*` where the `<Gate>` is a `quantum.custom` op it expect to replace (It's not what generated from frontend). Also you can just mark the attributes `catalyst.decomposition` and `catalyst.decomposition.target_op` at decomposition function, it still works. And this pass just **discover** those decomposition functions and **replace** the target operation with `call` to the function and rely on the Inliner interface to inline these decomposition function if needed. The stages of the `--decompose-lowering`: 1. `decompose_lowering.cpp`: Main pass that orchestrates the decomposition process 2. `DecomposeLoweringPatterns`: Pattern rewriting logic that replaces `quantum.custom` operations with function call 3. `QuantumInlinerInterface`: Dialect interface that enables MLIR's inliner to process quantum operations correctly 4. Remove unused decomposition function (if the inliner decide not to inline the certain function, then it will leave a `func.call`, so the func is used, shouldn't be removed) The type signature between decomposition function provided from the frontend is different to the `quantum.custom` op, `OpSignatureAnalyzer` does the trick to get the enough information to generate a function call to decomposition function. Current right now, frontend choose to generate the decomposition function with type: ``` (qreg, param*, inWires*, inCtrlWires*?, inCtrlValues*?) -> qreg ``` We need to figure out the information that need to pass to create the function call: qreg, `in wires indices`, and `in ctrl wires`. `OpSignatureAnalyzer` will use the target `quantum.custom` op (that one we need to replace) to traverse the qubit, and find out the qreg, and wire indices. The traversal logic based on the following assumption for the quantum dialect: 1. The ordering of qubits is preserved in quantum instructions 2. For other instructions, they will use a register, so will hit an extract before them It promise that every gates, the result (qubits) will match to the operands (qubits) at the same index. That's the important assumptions to support the traversal logic here. Traverse the qubit, match the index, keep going up until reach the `qauntum.extract` operation. After then, we use those information to generate a function call and rely on the Inliner in MLIR infra to replace it. **Benefits:** The decision to use MLIR's inlining infrastructure (`InlinerPass`) is to provide future-proofing and flexibility. **Possible Drawbacks:** **Related GitHub Issues:** [sc-98593] --------- Co-authored-by: Ali Asadi <[email protected]>
…talyst into feature/handle_gdecomp_v4
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Context:
Prototype PL's DecompositionGraph in C++ for integration with the Catalyst core compiler
Benefits:
Possible Drawbacks:
Related to:
#2062