For index type of induction variable, the indexing math is better
represented using affine ops such as `affine.delinearize_index`.
This also further demonstrates that some of these `affine` ops might
need to move to a different dialect. For one these ops only support
`IndexType` when they should be able to work with any integer type.
This change also includes some canonicalization patterns for
`affine.delinearize_index` operation to
1) Drop unit `basis` values
2) Remove the `delinearize_index` op when the `linear_index` is a loop
induction variable of a normalized loop and the `basis` is of size 1 and
is also the upper bound of the normalized loop.
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Signed-off-by: MaheshRavishankar <mahesh.ravishankar@gmail.com>
cca32174fe