Add verifier to aten.view to reject element type mismatches

`aten.view` maps to the shape-only overload (`aten::view(Tensor,
SymInt[])`), which preserves dtype. Without a verifier, invalid IR with
mismatched input/output element types reaches `genericViewLikeFold` and
crashes with an assertion failure in `DenseElementsAttr::get`.

Fixes #4479

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: rkayaith

include/torch-mlir/Dialect/Torch/IR/GeneratedTorchOps.td

@@ -13128,6 +13128,7 @@ def Torch_AtenViewOp : Torch_Op<"aten.view", [
     }
   }];
   let hasFolder = 1;
+  let hasVerifier = 1;
 }
 
 def Torch_AtenViewDtypeOp : Torch_Op<"aten.view.dtype", [

lib/Dialect/Torch/IR/TorchOps.cpp

@@ -1218,6 +1218,21 @@ void Aten_CastLongOp::getCanonicalizationPatterns(RewritePatternSet &patterns,
 // AtenViewOp
 //===----------------------------------------------------------------------===//
 
+LogicalResult AtenViewOp::verify() {
+  auto selfType = dyn_cast<BaseTensorType>(getSelf().getType());
+  auto resultType = dyn_cast<BaseTensorType>(getType());
+  if (!selfType || !resultType || !selfType.hasDtype() ||
+      !resultType.hasDtype())
+    return success();
+  if (selfType.getDtype() != resultType.getDtype())
+    return emitOpError("element type of input (")
+           << selfType.getDtype() << ") does not match element type of result ("
+           << resultType.getDtype()
+           << "); `aten.view` cannot change dtype, use `aten.view.dtype` for "
+              "dtype reinterpretation";
+  return success();
+}
+
 OpFoldResult AtenViewOp::fold(FoldAdaptor adaptor) {
   if (auto genericFold = genericViewLikeFold(adaptor.getSelf(), getType()))
     return genericFold;

projects/pt1/python/torch_mlir/jit_ir_importer/build_tools/torch_ods_gen.py

@@ -961,7 +961,7 @@ def emit_with_mutating_variants(key, **kwargs):
     emit("aten::_cast_Float : (Tensor, bool) -> (Tensor)", has_canonicalizer=True)
     emit("aten::_cast_Long : (Tensor, bool) -> (Tensor)", has_canonicalizer=True)
     emit("aten::type_as : (Tensor, Tensor) -> (Tensor)")
-    emit("aten::view : (Tensor, int[]) -> (Tensor)", has_folder=True)
+    emit("aten::view : (Tensor, int[]) -> (Tensor)", has_folder=True, has_verifier=True)
     emit("aten::view.dtype : (Tensor, int) -> (Tensor)")
     emit("aten::_unsafe_view : (Tensor, int[]) -> (Tensor)")
     emit("aten::where.self : (Tensor, Tensor, Tensor) -> (Tensor)", has_folder=True)

test/Dialect/Torch/invalid.mlir

@@ -403,3 +403,12 @@ func.func @torch.symbolic_int$no_shape_symbols(%arg0: !torch.vtensor<[?],f32>) -
   torch.bind_symbolic_shape %arg0, [%int0], affine_map<()[s0] -> (s0)> : !torch.vtensor<[?],f32>
   return %arg0 : !torch.vtensor<[?],f32>
 }
+
+// -----
+
+func.func @torch.aten.view$dtype_mismatch(%arg0: !torch.vtensor<[1],f32>) {
+  %shape = torch.prim.ListConstruct : () -> !torch.list<int>
+  // expected-error @below {{'torch.aten.view' op element type of input ('f32') does not match element type of result ('bf16')}}
+  torch.aten.view %arg0, %shape : !torch.vtensor<[1],f32>, !torch.list<int> -> !torch.vtensor<[],bf16>
+  return
+}