[all-commits] [llvm/llvm-project] 9f5cef: [mlir][Affine] Generalize the linearize(delineariz...

[Krzysztof Drewniak via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9f5cefebb482331796ceaebbfcebcd5aee1eb339
      https://github.com/llvm/llvm-project/commit/9f5cefebb482331796ceaebbfcebcd5aee1eb339
  Author: Krzysztof Drewniak <Krzysztof.Drewniak at amd.com>
  Date:   2025-01-03 (Fri, 03 Jan 2025)

  Changed paths:
    M mlir/include/mlir/Dialect/Affine/IR/AffineOps.td
    M mlir/lib/Dialect/Affine/IR/AffineOps.cpp
    M mlir/test/Dialect/Affine/canonicalize.mlir

  Log Message:
  -----------
  [mlir][Affine] Generalize the linearize(delinearize()) simplifications (#117637)

The existing canonicalization patterns would only cancel out cases where
the entire result list of an affine.delineraize_index was passed to an
affine.lineraize_index and the basis elements matched exactly (except
possibly for the outer bounds).

This was correct, but limited, and left open many cases where a
delinearize_index would take a series of divisions and modulos only for
a subsequent linearize_index to use additions and multiplications to
undo all that work.

This sort of simplification is reasably easy to observe at the level of
splititng and merging indexes, but difficult to perform once the
underlying arithmetic operations have been created.

Therefore, this commit generalizes the existing simplification logic.

Now, any run of two or more delinearize_index results that appears
within the argument list of a linearize_index operation with the same
basis (or where they're both at the outermost position and so can be
unbonded, or when `linearize_index disjoint` implies a bound not present
on the `delinearize_index`) will be reduced to one signle
delinearize_index output, whose basis element (that is, size or length)
is equal to the product of the sizes that were simplified away.

That is, we can now simplify

    %0:2 = affine.delinearize_index %n into (8, 8) : inde, index
%1 = affine.linearize_index [%x, %0#0, %0#1, %y] by (3, 8, 8, 5) : index

to the simpler

    %1 = affine.linearize_index [%x, %n, %y] by (3, 64, 5) : index

This new pattern also works with dynamically-sized basis values.

While I'm here, I fixed a bunch of typos in existing tests, and added a
new getPaddedBasis() method to make processing
potentially-underspecified basis elements simpler in some cases.



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