[Mlir-commits] [mlir] [mlir][vector] Add a pattern to fuse extract(constant_mask) (PR #81057)

[Han-Chung Wang]

hanhanW wrote:

I think it is embedded in the revert commit message. Let me copy it to here:

This pattern is producing incorrect IR. For example,

```mlir
func.func @extract_subvector_from_constant_mask() -> vector<16xi1> {
  %mask = vector.constant_mask [2, 3] : vector<16x16xi1>
  %extract = vector.extract %mask[8] : vector<16xi1> from vector<16x16xi1>
  return %extract : vector<16xi1>
}
```

Canonicalizes to

```mlir
func.func @extract_subvector_from_constant_mask() -> vector<16xi1> {
  %0 = vector.constant_mask [3] : vector<16xi1>
  return %0 : vector<16xi1>
}
```

Where it should be a zero mask because the extraction index (8) is
greater than the constant mask size along that dim (2).

https://github.com/llvm/llvm-project/pull/81057