3225f20ab1
[Stablehlo] use index type as dim size, avoid to generate index_cast ( #3526 )
...
For example, the original IR is:
```
module attributes {torch.debug_module_name = "Matmul3D"} {
func.func @forward(%arg0: tensor<?x?x?xf32>, %arg1: tensor<?x?x?xf32>) -> tensor<?x?x?xf32> {
%c0 = arith.constant 0 : index
%c1 = arith.constant 1 : index
%c2 = arith.constant 2 : index
%dim = tensor.dim %arg1, %c0 : tensor<?x?x?xf32>
%0 = arith.index_cast %dim : index to i64
%dim_0 = tensor.dim %arg1, %c1 : tensor<?x?x?xf32>
%1 = arith.index_cast %dim_0 : index to i64
%dim_1 = tensor.dim %arg1, %c2 : tensor<?x?x?xf32>
%2 = arith.index_cast %dim_1 : index to i64
%from_elements = tensor.from_elements %0, %1, %2 : tensor<3xi64>
%3 = stablehlo.dynamic_broadcast_in_dim %arg1, %from_elements, dims = [0, 1, 2] : (tensor<?x?x?xf32>, tensor<3xi64>) -> tensor<?x?x?xf32>
%4 = stablehlo.dot_general %arg0, %3, batching_dims = [0] x [0], contracting_dims = [2] x [1] : (tensor<?x?x?xf32>, tensor<?x?x?xf32>) -> tensor<?x?x?xf32>
return %4 : tensor<?x?x?xf32>
}
}
```
After using IndexType, the IR is:
```
module attributes {torch.debug_module_name = "Matmul3D"} {
func.func @forward(%arg0: tensor<?x?x?xf32>, %arg1: tensor<?x?x?xf32>) -> tensor<?x?x?xf32> {
%c0 = arith.constant 0 : index
%c1 = arith.constant 1 : index
%c2 = arith.constant 2 : index
%dim = tensor.dim %arg1, %c0 : tensor<?x?x?xf32>
%dim_0 = tensor.dim %arg1, %c1 : tensor<?x?x?xf32>
%dim_1 = tensor.dim %arg1, %c2 : tensor<?x?x?xf32>
%from_elements = tensor.from_elements %dim, %dim_0, %dim_1 : tensor<3xindex>
%0 = stablehlo.dynamic_broadcast_in_dim %arg1, %from_elements, dims = [0, 1, 2] : (tensor<?x?x?xf32>, tensor<3xindex>) -> tensor<?x?x?xf32>
%1 = stablehlo.dot_general %arg0, %0, batching_dims = [0] x [0], contracting_dims = [2] x [1] : (tensor<?x?x?xf32>, tensor<?x?x?xf32>) -> tensor<?x?x?xf32>
return %1 : tensor<?x?x?xf32>
}
}
```
The benefits of using IndexType on shape tensor:
* simplify the IR, avoid to generate `arith.index_cast`
* let backend compiler have a chance to decide the index width of shape
tensor
* let stablehlo backend have a chance to serialize dynamic shape IR by
[shape_legalize_to_stablehlo](https://github.com/openxla/stablehlo/blob/main/stablehlo/tests/shape_legalize_to_stablehlo.mlir )
2024-07-07 18:03:03 +08:00
Yuanqiang Liu
Peiming Liu
Stella Laurenzo
Jiawei Wu