[Python Kernel] bool to int type casting issue

[1tnguyen]

The below kernel

@cudaq.kernel
def kernel():
    data = cudaq.qvector(2)
    aux = cudaq.qubit()
    x(aux)
    bit = mz(aux)
    # Compare to 1
    if bit == 1:
        x(data[0])
    mz(data)

results in the following IR:

 %6 = bitcast %Result* %5 to i1*
 %7 = load i1, i1* %6, align 1
 %8 = sext i1 %7 to i64
 %9 = icmp eq i64 %8, 1

If bit==True (%7 == true in the above IR), it looks like the icmp returns false. A quick search of LLVM doc indicated that sext i1 ... i64 may convert true to -1.

In fact, the below kernel resulted in the correct distribution (may need the fixes from #1619 to get the measurement feedback detection working properly).

@cudaq.kernel
def kernel5():
    data = cudaq.qvector(2)
    aux = cudaq.qubit()
    x(aux)
    bit = mz(aux)
    # Compare to -1
    if bit == -1:
        x(data[0])
    mz(data)

[1tnguyen]

@schweitzpgi suggested that we should use cc::CastOpMode::Unsigned in this case.