[Mlir-commits] [mlir] [mlir][linalg] Add broadcast splat to fill canonicalization (PR #195980)

[Hocky Yudhiono]

hockyy wrote:

> Here too, the fill seems superfluous.

Hi, for this one, if we change it to splat, it cannot handle dynamic cases. Should we bail-out in this case? wdyt?

```
module {
  func.func @broadcast_splat_constant_dynamic_shape(%arg0: tensor<?x3xf32>) -> tensor<?x3xf32> {
    %cst = arith.constant dense<1.000000e+00> : tensor<3xf32>
    %broadcasted = linalg.broadcast ins(%cst : tensor<3xf32>) outs(%arg0 : tensor<?x3xf32>) dimensions = [0] 
    return %broadcasted : tensor<?x3xf32>
  }
}

hocky at hocky:~/llvm/llvm-project/build_clion$ mlir-opt why.mlir  --canonicalize
module {
  func.func @broadcast_splat_constant_dynamic_shape(%arg0: tensor<?x3xf32>) -> tensor<?x3xf32> {
    %cst = arith.constant 1.000000e+00 : f32
    %0 = linalg.fill ins(%cst : f32) outs(%arg0 : tensor<?x3xf32>) -> tensor<?x3xf32>
    return %0 : tensor<?x3xf32>
  }
}
```

https://github.com/llvm/llvm-project/pull/195980