[llvm-bugs] [Bug 161569] scf for loop canonicalizations dont propagate

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Issue	161569
Summary	scf for loop canonicalizations dont propagate
Labels	new issue
Assignees
Reporter	nirvedhmeshram

    Consider these tests
```
func.func @scf_for_canonicalize_min(%A : memref<i64>) {
  %c0 = arith.constant 0 : index
  %c2 = arith.constant 2 : index
  %c638 = arith.constant 638 : index

  scf.for %i = %c0 to %c638 step %c2  {
    %1 = affine.min affine_map<(d0) -> (10239, d0 * 16)>(%i)
    %2 = affine.min affine_map<(d0) -> (-d0 + 10239, 32)>(%1)
    %3 = arith.index_cast %2: index to i64
 memref.store %3, %A[]: memref<i64>
  }
  return
}

// -----
func.func @scf_for_canonicalize_min(%A : memref<i64>) {
  %c0 = arith.constant 0 : index
  %c2 = arith.constant 2 : index
  %c638 = arith.constant 638 : index

  scf.for %i = %c0 to %c638 step %c2  {
    %2 = affine.min affine_map<(d0) -> (-d0 * 16 + 10239, 32)>(%i)
    %3 = arith.index_cast %2: index to i64
    memref.store %3, %A[]: memref<i64>
  }
 return
}
```
With
```
mlir-opt test.mlir -scf-for-loop-canonicalization --split-input-file --mlir-print-local-scope
```

We get the following outputs
```
  func.func @scf_for_canonicalize_min(%arg0: memref<i64>) {
 %c0 = arith.constant 0 : index
    %c2 = arith.constant 2 : index
 %c638 = arith.constant 638 : index
    scf.for %arg1 = %c0 to %c638 step %c2 {
      %0 = affine.apply affine_map<(d0) -> (d0 * 16)>(%arg1)
      %1 = affine.min affine_map<(d0) -> (-d0 + 10239, 32)>(%0)
      %2 = arith.index_cast %1 : index to i64
      memref.store %2, %arg0[] : memref<i64>
    }
    return
  }
// -----
  func.func @scf_for_canonicalize_min(%arg0: memref<i64>) {
    %c32_i64 = arith.constant 32 : i64
    %c0 = arith.constant 0 : index
    %c2 = arith.constant 2 : index
    %c638 = arith.constant 638 : index
    scf.for %arg1 = %c0 to %c638 step %c2 {
      memref.store %c32_i64, %arg0[] : memref<i64>
    }
    return
  }
```
We could not canonicalize the second affine.min in the first test but can do it in the second test because it directly  takes the induction var as an input.  What do we need to do to propagate the canonicalization?

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