[mlir][TosaToLinalg] Fix TosaToLinalg to restrict tosa.cast types to integer or float (llvm#128859)

This PR fixes a bug where `TosaToLinalg` incorrectly allows `tosa.cast`
to accept types other than integer or float.
Fixes llvm#116342.

Author: CoTinker

mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp

@@ -524,6 +524,11 @@ static Value createLinalgBodyCalculationForElementwiseOp(
   if (isa<tosa::CastOp>(op)) {
     Type srcTy = elementTy;
     Type dstTy = resultTypes.front();
+    if (!srcTy.isIntOrFloat() || !dstTy.isIntOrFloat()) {
+      (void)rewriter.notifyMatchFailure(op, "unsupported type");
+      return nullptr;
+    }
+
     bool bitExtend =
         srcTy.getIntOrFloatBitWidth() < dstTy.getIntOrFloatBitWidth();
 

mlir/test/Conversion/TosaToLinalg/tosa-to-linalg-invalid.mlir

@@ -54,3 +54,11 @@ func.func @test_add_2d_different_ranks(%arg0: tensor<3x4xf32>, %arg1: tensor<2x3
   %0 = "tosa.add"(%arg0, %arg1) : (tensor<3x4xf32>, tensor<2x3x4xf32>) -> tensor<2x3x4xf32>
   return %0 : tensor<2x3x4xf32>
 }
+
+// -----
+
+func.func @cast_unsupported_type(%arg0: tensor<13x21x3xi32>) -> tensor<13x21x3x!quant.uniform<i16:f32, 0.078431375324726104:128>> {
+  // expected-error@+1 {{failed to legalize operation 'tosa.cast'}}
+  %0 = tosa.cast %arg0 : (tensor<13x21x3xi32>) -> tensor<13x21x3x!quant.uniform<i16:f32, 0.078431375324726104:128>>
+  return %0 : tensor<13x21x3x!quant.uniform<i16:f32, 0.078431375324726104:128>>
+}