[Mlir-commits] [mlir] [mlir][tensor] Fold pack and unpack of empty input tensor (PR #92247)

[llvmlistbot at llvm.org]

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@@ -64,6 +64,73 @@ func.func @rank_reducing_empty_tensor_extract(%sz : index, %idx : index) -> tens
   return %r: tensor<2xf32>
 }
 
+func.func @pack_empty(%arg0: tensor<8x8x32x32xf32>) -> tensor<8x8x32x32xf32> {
+  %empty_unpacked = tensor.empty() : tensor<256x256xf32>
+  %packed = tensor.pack %empty_unpacked
+    inner_dims_pos = [0, 1] inner_tiles = [32, 32]
+    into %arg0 : tensor<256x256xf32> -> tensor<8x8x32x32xf32>
+  return %packed : tensor<8x8x32x32xf32>
+}
+
+// CHECK-LABEL: func.func @pack_empty(
+// CHECK-SAME:   %[[T:.+]]: tensor<8x8x32x32xf32>
+// CHECK-NOT:    tensor.pack
+// CHECK:        return %[[T]] : tensor<8x8x32x32xf32>
+
+func.func @pack_empty_dynamic(%arg0: tensor<?x?x?x?xf32>, %dim0: index, %dim1: index) -> tensor<?x?x?x?xf32> {
+  %empty_unpacked = tensor.empty(%dim0, %dim1) : tensor<?x?xf32>
+  %packed = tensor.pack %empty_unpacked
+    inner_dims_pos = [0, 1] inner_tiles = [32, 32]
+    into %arg0 : tensor<?x?xf32> -> tensor<?x?x?x?xf32>
+  return %packed : tensor<?x?x?x?xf32>
+}
+
+// CHECK-LABEL: func.func @pack_empty_dynamic(
+// CHECK-SAME:   %[[T:.+]]: tensor<?x?x?x?xf32>
----------------
MaheshRavishankar wrote:

Nit: Please check that the tensor shape is what you expect by looking at the operands for `tensor.empty`

https://github.com/llvm/llvm-project/pull/92247