Goals:
1. To add syntax and semantic to 'batch_matmul' without changing any of
the existing syntax expectations for current usage. batch_matmul is
still just batch_matmul.
2. Move the definition of batch_matmul from linalg OpDsl to tablegen ODS
infra.
Scope of this patch:
To expose broadcast and transpose semantics on the 'batch_matmul'.
The broadcast and transpose semantic are as follows:
By default, 'linalg.batch_matmul' behavior will remain as is. Broadcast
and Transpose semantics can be applied by specifying the explicit
attribute 'indexing_maps' as shown below. This is a list attribute, so
the list must include all the maps if specified.
Example Transpose:
```
linalg.batch_matmul indexing_maps = [
affine_map< (d0, d1, d2, d3) -> (d0, d3, d1)>, //transpose
affine_map< (d0, d1, d2, d3) -> (d0, d3, d2)>,
affine_map< (d0, d1, d2, d3) -> (d0, d1, d2)>
]
ins (%arg0, %arg1: memref<2x5x3xf32>,memref<2x5x7xf32>)
outs (%arg2: memref<2x3x7xf32>)
```
Example Broadcast:
```
linalg.batch_matmul indexing_maps = [
affine_map< (d0, d1, d2, d3) -> (d3)>, //broadcast
affine_map< (d0, d1, d2, d3) -> (d0, d3, d2)>,
affine_map< (d0, d1, d2, d3) -> (d0, d1, d2)>
]
ins (%arg0, %arg1: memref<5xf32>,memref<2x5x7xf32>)
outs (%arg2: memref<2x3x7xf32>)
```
Example Broadcast and transpose:
```
linalg.batch_matmul indexing_maps = [
affine_map< (d0, d1, d2, d3) -> (d1, d3)>, //broadcast
affine_map< (d0, d1, d2, d3) -> (d0, d2, d3)>, //transpose
affine_map< (d0, d1, d2, d3) -> (d0, d1, d2)>
]
ins (%arg0, %arg1: memref<3x5xf32>, memref<2x7x5xf32>)
outs (%arg2: memref<2x3x7xf32>)
```
RFCs and related PR:
https://discourse.llvm.org/t/rfc-linalg-opdsl-constant-list-attribute-definition/80149https://discourse.llvm.org/t/rfc-op-explosion-in-linalg/82863https://discourse.llvm.org/t/rfc-mlir-linalg-operation-tree/83586https://github.com/llvm/llvm-project/pull/115319