[Mlir-commits] [mlir] [mlir][Vector] Improve support for vector.extract(broadcast) (PR #116234)

[Andrzej Warzyński]

================
@@ -747,57 +775,51 @@ func.func @fold_extract_broadcast_negative(%a : vector<1x1xf32>) -> vector<4xf32
 // CHECK-LABEL: fold_extract_splat
 //  CHECK-SAME:   %[[A:.*]]: f32
 //       CHECK:   return %[[A]] : f32
-func.func @fold_extract_splat(%a : f32) -> f32 {
+func.func @fold_extract_splat(%a : f32, %idx0 : index, %idx1 : index, %idx2 : index) -> f32 {
   %b = vector.splat %a : vector<1x2x4xf32>
-  %r = vector.extract %b[0, 1, 2] : f32 from vector<1x2x4xf32>
+  %r = vector.extract %b[%idx0, %idx1, %idx2] : f32 from vector<1x2x4xf32>
   return %r : f32
 }
 
 // -----
 
-// CHECK-LABEL: fold_extract_broadcast_vector
-//  CHECK-SAME:   %[[A:.*]]: vector<4xf32>
-//       CHECK:   return %[[A]] : vector<4xf32>
-func.func @fold_extract_broadcast_vector(%a : vector<4xf32>) -> vector<4xf32> {
-  %b = vector.broadcast %a : vector<4xf32> to vector<1x2x4xf32>
-  %r = vector.extract %b[0, 1] : vector<4xf32> from vector<1x2x4xf32>
-  return %r : vector<4xf32>
-}
-
-// -----
-
-// CHECK-LABEL: fold_extract_broadcast
-//  CHECK-SAME:   %[[A:.*]]: vector<4xf32>
-//       CHECK:   %[[R:.*]] = vector.extract %[[A]][2] : f32 from vector<4xf32>
+// CHECK-LABEL: fold_extract_broadcast_dim1_broadcasting
+//  CHECK-SAME:   %[[A:.*]]: vector<2x1xf32>
+//  CHECK-SAME:   %[[IDX:.*]]: index, %[[IDX1:.*]]: index, %[[IDX2:.*]]: index
+//       CHECK:   %[[R:.*]] = vector.extract %[[A]][%[[IDX1]], 0] : f32 from vector<2x1xf32>
 //       CHECK:   return %[[R]] : f32
-func.func @fold_extract_broadcast(%a : vector<4xf32>) -> f32 {
-  %b = vector.broadcast %a : vector<4xf32> to vector<1x2x4xf32>
-  %r = vector.extract %b[0, 1, 2] : f32 from vector<1x2x4xf32>
+func.func @fold_extract_broadcast_dim1_broadcasting(%a : vector<2x1xf32>, 
+  %idx : index, %idx1 : index, %idx2 : index) -> f32 {
+  %b = vector.broadcast %a : vector<2x1xf32> to vector<1x2x4xf32>
+  %r = vector.extract %b[%idx, %idx1, %idx2] : f32 from vector<1x2x4xf32>
   return %r : f32
 }
 
 // -----
 
-// CHECK-LABEL: fold_extract_broadcast
+// CHECK-LABEL: fold_extract_broadcast_to_higher_rank
 //       CHECK:   %[[B:.*]] = vector.broadcast %{{.*}} : f32 to vector<4xf32>
 //       CHECK:   return %[[B]] : vector<4xf32>
-func.func @fold_extract_broadcast(%a : f32) -> vector<4xf32> {
+func.func @fold_extract_broadcast_to_higher_rank(%a : f32, %idx0 : index, %idx1 : index) 
+  -> vector<4xf32> {
   %b = vector.broadcast %a : f32 to vector<1x2x4xf32>
-  %r = vector.extract %b[0, 1] : vector<4xf32> from vector<1x2x4xf32>
+  %r = vector.extract %b[%idx0, %idx1] : vector<4xf32> from vector<1x2x4xf32>
   return %r : vector<4xf32>
----------------
banach-space wrote:

Isn't this similar to @fold_extract_broadcast_diff_input_output_vec? Also, isn't every broadcast _broadcasting_ to something that's higher rank? (apart from "dim1" broadcasting)

In fact, looks like:
* `@fold_extract_broadcast_diff_input_output_vec`
* `@fold_extract_broadcast_to_higher_rank`, and
* `@fold_extract_broadcast_to_equal_rank`

are very similar. If there's an actual difference, please add a comment what makes these cases special :)

https://github.com/llvm/llvm-project/pull/116234