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77db8b08c8
Restrict `DropInnerMostUnitDimsTransferRead` so that it fails when one
of the indices to be dropped could be != 0, e.g.
```mlir
func.func @negative_example(%A: memref<16x1xf32>, %i:index, %j:index) -> (vector<8x1xf32>) {
%f0 = arith.constant 0.0 : f32
%1 = vector.transfer_read %A[%i, %j], %f0 : memref<16x1xf32>, vector<8x1xf32>
return %1 : vector<8x1xf32>
}
```
This is an edge case that could represent an out-of-bounds access,
though that will depend on the actual value of `%j`. Importantly,
_without this change_ it would be transformed as follows:
```mlir
func.func @negative_example(%arg0: memref<16x1xf32>, %arg1: index, %arg2: index) -> vector<8x1xf32> {
%cst = arith.constant 0.000000e+00 : f32
%subview = memref.subview %arg0[0, 0] [16, 1] [1, 1] : memref<16x1xf32> to memref<16xf32, strided<[1]>>
%0 = vector.transfer_read %subview[%arg1], %cst : memref<16xf32, strided<[1]>>, vector<8xf32>
%1 = vector.shape_cast %0 : vector<8xf32> to vector<8x1xf32>
return %1 : vector<8x1xf32>
}
```
This is incorrect - `%arg2` is ignored. Hence the extra restriction to
avoid such cases.
NOTE: This PR is limited to tests for `vector.transfer_read`.