Test for overlap with all quantum operations in MergeCircuitsPass (#244)

Handle quir operations in addition to barriers between quir.circuit_ops and test for
qubit overlap in the same way currently being applied to quir.barriers.

Author: bcdonovan

lib/Dialect/QUIR/Transforms/MergeCircuits.cpp

@@ -96,17 +96,16 @@ struct CircuitAndCircuitPattern : public OpRewritePattern<CallCircuitOp> {
       if (nextCallCircuitOp)
         break;
 
-      // check for overlapping BarrierOp and fail if found
-      auto barrierOp = dyn_cast<BarrierOp>(*secondOp);
-      if (barrierOp) {
-        std::set<uint> firstQubits =
-            QubitOpInterface::getOperatedQubits(callCircuitOp);
-        std::set<uint> secondQubits =
-            QubitOpInterface::getOperatedQubits(barrierOp);
-
-        if (QubitOpInterface::qubitSetsOverlap(firstQubits, secondQubits))
-          return failure();
-      }
+      // check for overlap in qubits between the circuit and the
+      // next quantum circuit which is not a CallCircuit
+      // fail if there is overlap
+      std::set<uint> firstQubits =
+          QubitOpInterface::getOperatedQubits(callCircuitOp);
+      std::set<uint> secondQubits =
+          QubitOpInterface::getOperatedQubits(*secondOp);
+
+      if (QubitOpInterface::qubitSetsOverlap(firstQubits, secondQubits))
+        return failure();
 
       searchOp = *secondOp;
     }

releasenotes/notes/test-overlap-all-5d170626357867d6.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixes bug related to assumption in MergeCircuitsPass that all quantum instructions
+    are located in a quir.circuit when attempting to merge circuits. Applies the qubit overlap
+    test to all quantum operations in between quir.call_circuit calls.

test/Dialect/QUIR/Transforms/merge-circuits.mlir

@@ -57,6 +57,11 @@ module {
     %1 = quir.measure(%arg0) : (!quir.qubit<1>) -> i1
     quir.return %0, %1: i1, i1
   }
+  quir.circuit @circuit_9(%arg0: !quir.qubit<1>) -> (i1, i1) {
+    %0 = quir.measure(%arg0) : (!quir.qubit<1>) -> i1
+    %1 = quir.measure(%arg0) : (!quir.qubit<1>) -> i1
+    quir.return %0, %1: i1, i1
+  }
   // CHECK: @circuit_0_q0_circuit_1_q1(%arg0: !quir.qubit<1>
   // CHECK: %0 = quir.measure(%arg0) : (!quir.qubit<1>) -> i1
   // CHECK: %1 = quir.measure(%arg1) : (!quir.qubit<1>) -> i1
@@ -126,6 +131,15 @@ module {
     %17:2 = quir.call_circuit @circuit_8(%0) : (!quir.qubit<1>) -> (i1, i1)
     // CHECK-NOT: %{{.*}}:4 = quir.call_circuit @circuit_8_q0_circuit_8_q0(%0) : (!quir.qubit<1>) -> (i1, i1, i1, i1)
 
+    quir.barrier %0, %1, %200, %201, %202 : (!quir.qubit<1>, !quir.qubit<1>, !quir.qubit<1>, !quir.qubit<1>, !quir.qubit<1>) -> ()
+    %18:2 = quir.call_circuit @circuit_9(%0) : (!quir.qubit<1>) -> (i1, i1)
+    // CHECK: %{{.*}}:2 = quir.call_circuit @circuit_9_q0(%0) : (!quir.qubit<1>) -> (i1, i1)
+    %19 = quir.measure(%0) {quir.noReportRuntime} : (!quir.qubit<1>) -> i1
+    // CHECK: %{{.*}} = quir.measure(%0) {quir.noReportRuntime} : (!quir.qubit<1>) -> i1
+    %20:2 = quir.call_circuit @circuit_9(%0) : (!quir.qubit<1>) -> (i1, i1)
+    // CHECK: %{{.*}}:2 = quir.call_circuit @circuit_9_q0(%0) : (!quir.qubit<1>) -> (i1, i1)
+    // CHECK-NOT: %{{.*}}:4 = quir.call_circuit @circuit_9_q0_circuit_9_q0(%0) : (!quir.qubit<1>) -> (i1, i1, i1, i1)
+
     %c0_i32 = arith.constant 0 : i32
     return %c0_i32 : i32
   }