[mlir][Tosa] Allow scalar tensors to be unranked in the TOSA dialect (#150399)

### Summary
This PR resolves #149779

Author: woruyu

mlir/include/mlir/Dialect/Tosa/IR/TosaTypesBase.td

@@ -150,7 +150,7 @@ class Tosa_TensorOfOrNone<list<Type> allowedTypes, string description = ""> :
 
 def Tosa_Rank0Tensor : TosaTensorRankOf<[Tosa_AnyNumber], [0]>;
 
-def Tosa_ScalarTensor : TosaScalarTensorOf<[Tosa_AnyNumber], [1]>;
+def Tosa_ScalarTensor : AnyTypeOf<[TosaUnrankedTensorOf<[Tosa_Int, AnyFloat]>, TosaScalarTensorOf<[Tosa_AnyNumber], [1]>]>;
 def Tosa_ScalarInt8Tensor : TosaScalarTensorOf<[Tosa_Int8], [1]>;
 def Tosa_ScalarIntOrFloatTensor : AnyTypeOf<[TosaUnrankedTensorOf<[Tosa_Int, AnyFloat]>, TosaScalarTensorOf<[Tosa_Int, AnyFloat], [1]>]>;
 

mlir/test/Dialect/Tosa/invalid.mlir

@@ -300,7 +300,7 @@ func.func @test_concat_input_rank_mismatch(%arg0: tensor<1x2x3xf32>, %arg1: tens
 func.func @test_pad_invalid_padConst_rank(%arg0: tensor<13x21xf32>) {
   %0 = tosa.const_shape {values = dense<1> : tensor<4xindex>} : () -> !tosa.shape<4>
   %1 = "tosa.const"() {values = dense<3.14> : tensor<2xf32>} : () -> tensor<2xf32>
-  // expected-error@+1 {{'tosa.pad' op operand #2 must be tosa-conformant scalar tensor of number values, but got 'tensor<2xf32>'}}
+  // expected-error@+1 {{'tosa.pad' op operand #2 must be tosa-conformant unranked tensor of unsigned integer or signless integer or floating-point values or tosa-conformant scalar tensor of number values, but got 'tensor<2xf32>'}}
   %2 = tosa.pad %arg0, %0, %1 : (tensor<13x21xf32>, !tosa.shape<4>, tensor<2xf32>) -> tensor<13x21xf32>
   return
 }
@@ -1006,7 +1006,7 @@ func.func @test_non_tosa_ops() {
 func.func @test_pad_rank0_pad_const(%arg0: tensor<13x21x3xf8E4M3FN>) -> tensor<13x21x3xf8E5M2> {
   %padding = tosa.const_shape {values = dense<0> : tensor<6xindex>} : () -> !tosa.shape<6>
   %cst = "tosa.const"() { values = dense<-0.0> : tensor<f8E4M3FN> } : () -> tensor<f8E4M3FN>
-  // expected-error@+1 {{'tosa.pad' op operand #2 must be tosa-conformant scalar tensor of number values, but got 'tensor<f8E4M3FN>'}}
+  // expected-error@+1 {{'tosa.pad' op operand #2 must be tosa-conformant unranked tensor of unsigned integer or signless integer or floating-point values or tosa-conformant scalar tensor of number values, but got 'tensor<f8E4M3FN>'}}
   %0 = tosa.pad %arg0, %padding, %cst : (tensor<13x21x3xf8E4M3FN>, !tosa.shape<6>, tensor<f8E4M3FN>) -> tensor<13x21x3xf8E5M2>
   return %0 : tensor<13x21x3xf8E5M2>
 }

mlir/test/Dialect/Tosa/tosa-infer-shapes.mlir

@@ -344,6 +344,19 @@ func.func @test_unranked_zero_points_matmul(%arg0: tensor<1x2x3xf32>, %arg1: ten
 
 // -----
 
+// CHECK-LABEL: @test_accepts_unranked_scalar_tensor
+func.func @test_accepts_unranked_scalar_tensor(%arg0: tensor<1x2x2xf32>, %arg1: tensor<1xf32>) -> tensor<*xf32> {
+  // CHECK: %[[ZP:.*]] = tosa.cast %arg1 : (tensor<1xf32>) -> tensor<1xf32>
+  %0 = tosa.cast %arg1 : (tensor<1xf32>) -> tensor<*xf32>
+  // CHECK: %[[SHAPE:.*]] = tosa.const_shape
+  %1 = tosa.const_shape {values = dense<[0, 0, 0, 1, 0, 1]> : tensor<6xindex>} : () -> !tosa.shape<6>
+  // CHECK: tosa.pad %arg0, %[[SHAPE]], %[[ZP]] : (tensor<1x2x2xf32>, !tosa.shape<6>, tensor<1xf32>) -> tensor<1x3x3xf32>
+  %2 = tosa.pad %arg0, %1, %0 : (tensor<1x2x2xf32>, !tosa.shape<6>, tensor<*xf32>) -> tensor<*xf32>
+  return %2 : tensor<*xf32>
+}
+
+// -----
+
 // CHECK-LABEL: @test_table_static
 func.func @test_table_static(%arg0 : tensor<4x5xi16>, %arg1 : tensor<513xi16>) -> () {
   // CHECK:tosa.table %arg0, %arg1 : (tensor<4x5xi16>, tensor<513xi16>) -> tensor<4x5xi16>