As the documentation for -affine-expand-index-ops says,
affine.delinearize_index and affine.linearize_index don't need to be
expanded into the affine dialect.
Expanding these operations into affine.apply operations can introduce
unwanted "simplifications", mainly translations of `(dN mod C + ...)` to
`(dN + ... - (dN floordiv C) * C)` and similar, which create worse
generated code. This commit resolves this issue by expanding out
affine.delanierize_index directly.
In addition, the lowering of affine.linearize_index now sorts the
operands by loop-independence, allowing an increased amount of
loop-invariant code motion after lowering.
The old behavior is preserved as -expand-affine-index-ops-as-affine but
is no longer the default
9e8200c718