Hello all,

I found that the output of mlir/test/Dialect/Linalg/drop-unit-extent-dims.mlir contains linalg.generic that does summation but its iterator type still parallel:

```
#map = affine_map<(d0) -> (d0)>
module {
func @unit_dim_for_both_reduction(%arg0: tensor<1x?x1x1xf32>) -> tensor<1x1xf32> {
%cst = arith.constant 1.000000e+00 : f32
%0 = linalg.tensor_collapse_shape %arg0 [[0, 1, 2, 3]] : tensor<1x?x1x1xf32> into tensor<?xf32>
%1 = linalg.init_tensor [1] : tensor<1xf32>
%2 = linalg.fill(%cst, %1) : f32, tensor<1xf32> -> tensor<1xf32>
%3 = linalg.generic {indexing_maps = [#map, #map], iterator_types = ["parallel"]} ins(%0 : tensor<?xf32>) outs(%2 : tensor<1xf32>) {
^bb0(%arg1: f32, %arg2: f32): // no predecessors
%5 = arith.addf %arg1, %arg2 : f32
linalg.yield %5 : f32
} -> tensor<1xf32>
%4 = linalg.tensor_expand_shape %3 [[0, 1]] : tensor<1xf32> into tensor<1x1xf32>
return %4 : tensor<1x1xf32>
}
}
```

IIUC the iterator type should be â€śreductionâ€ť because the loop is doing a reduction.

Is my understanding wrong, or is it a bug in the test?