The first test case added in the LIT test demonstrates the problem.
Even though we did not consider the inner loop as a candidate for
the transformation due to the array_coor with a slice, we decided to
version the outer loop for the same function argument.
During the cloning of the outer loop we dropped the slicing completely
producing invalid code.
I restructured the code so that we record all arg uses that cannot be
transformed (regardless of the reason), and then fixup the usage
information across the loop nests. I also noticed that we may generate
redundant contiguity checks for the inner loops, so I fixed it
since it was easy with the new way of keeping the usage data.
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