[TORCH] Improve type refinement for aten.cat. (#1908)

* [TORCH] Fix type refinement for aten.cat.

* Add test.

* Address comments.

* Update.

* Update.

* Update.

* Update.

* Update.

---------

Co-authored-by: Ziheng Jiang <ziheng.jiang@bytedance.com>

e2e_testing/xfail_sets.py

@@ -277,6 +277,7 @@ STABLEHLO_PASS_SET = {
     "FlattenStaticModule_basic",
     "FlattenRank0Module_basic",
     "TensorsConcatNegativeDimModule_basic",
+    "TensorsConcatPromoteDTypeModule_basic",
     "LiftFreshCopyModule_basic",
     "Mlp2LayerModuleNoBias_basic",
     "NumelModule_basic",
@@ -803,6 +804,7 @@ LTC_XFAIL_SET = {
     "SubFloatModule_basic",
     "SubIntModule_basic",
     "TensorsConcatNegativeDimModule_basic",
+    "TensorsConcatPromoteDTypeModule_basic",
     "TensorToBoolZeroRank_basic",
     "TensorToBool_basic",
     "TensorToFloatZeroRank_basic",

lib/Conversion/TorchToLinalg/DataMovement.cpp

@@ -1117,6 +1117,18 @@ public:
 
     RankedTensorType newResultType =
         typeConverter->convertType(op.getType()).cast<RankedTensorType>();
+
+    auto outElemType = newResultType.getElementType();
+    auto dtypePromoteBody = [&](OpBuilder &builder, Location loc,
+                        ValueRange payloadArgs) {
+      Value elem = convertScalarToDtype(builder, loc, payloadArgs[0], outElemType);
+      builder.create<linalg::YieldOp>(loc, elem);
+    };
+    for (size_t i = 0; i < tensors.size(); ++i) {
+      tensors[i] = torch_to_linalg::createElementwiseLinalgGeneric(
+          rewriter, loc, {tensors[i]}, outElemType, dtypePromoteBody);
+    }
+
     int rank = newResultType.getRank();
     SmallVector<Value> offsets, sizes, strides;
     sizes.reserve(rank);

lib/Dialect/Torch/Transforms/RefineTypes.cpp

@@ -112,24 +112,6 @@ static torch_upstream::TypeKind getTypeKind(Type type) {
   return torch_upstream::TypeKind::AnyType;
 }
 
-/// Returns the dtype that assumes information from both `lhs` and `rhs`.
-/// Returns `std::nullopt` if the types are contradictory. Note this can only
-/// be used on the `dtype` from tensors and can't be used on other types like
-/// scalar types.
-static std::optional<Type> meetElementTypes(Type lhs, Type rhs) {
-  auto isNullOrBuiltIn = [](Type type) { return !type || isBuiltInType(type); };
-  (void)isNullOrBuiltIn;
-  assert(isNullOrBuiltIn(lhs) && "`lhs` must be a builtin type");
-  assert(isNullOrBuiltIn(rhs) && "`rhs` must be a builtin type");
-
-  if (!lhs)
-    return rhs;
-  if (!rhs)
-    return lhs;
-  if (lhs == rhs)
-    return lhs;
-  return std::nullopt;
-}
 
 enum class OptionalKnowledge {
   unKnown,
@@ -1446,19 +1428,14 @@ void TypeAnalysis::visitAtenCatOp(AtenCatOp op,
     return;
   }
 
-  auto tensors = llvm::to_vector<4>(
-      llvm::map_range(listConstruct.getElements(), [&](Value v) -> ValueKnowledge {
-        return getLatticeElement(v)->getValue();
+  SmallVector<ValueKnowledge*> tensors = llvm::to_vector(
+      llvm::map_range(listConstruct.getElements(), [&](Value v) -> ValueKnowledge* {
+        return &getLatticeElement(v)->getValue();
       }));
-  for (auto tensor : tensors) {
-    auto newDtype = meetElementTypes(knowledge.dtype, tensor.dtype);
-    if (!newDtype.has_value()) {
-      incorporateKnowledge(op.getResult(), knowledge);
-      return;
-    }
-    knowledge.dtype = newDtype.value();
-  }
-  incorporateKnowledge(op.getResult(), knowledge);
+
+  knowledge.dtype = getPromotedResultTypeAssumingNonZeroRank(
+      op->getContext(), tensors);
+  incorporateKnowledge(op->getResult(0), knowledge);
 }
 
 void TypeAnalysis::visitNumToTensorOp(PrimNumToTensorScalarOp op) {

python/torch_mlir_e2e_test/test_suite/basic.py

@@ -621,6 +621,32 @@ def TensorsConcatNegativeDimModule_basic(module, tu: TestUtils):
 # ==============================================================================
 
 
+class TensorsConcatPromoteDTypeModule(torch.nn.Module):
+
+    def __init__(self):
+        super().__init__()
+
+    @export
+    @annotate_args([
+        None,
+        ([-1, -1, -1], torch.bool, True),
+        ([-1, -1, -1], torch.int32, True),
+        ([-1, -1, -1], torch.int64, True),
+    ])
+    def forward(self, x, y, z):
+        return torch.cat([x, y, z], dim=-2)
+
+
+@register_test_case(module_factory=lambda: TensorsConcatPromoteDTypeModule())
+def TensorsConcatPromoteDTypeModule_basic(module, tu: TestUtils):
+    module.forward(tu.randint(2, 2, 4, low=0, high=2).bool(),
+                   tu.randint(2, 1, 4, low=0, high=100).int(),
+                   tu.randint(2, 3, 4, low=0, high=100).long())
+
+
+# ==============================================================================
+
+
 class GatherModule(torch.nn.Module):
 
     def __init__(self):

test/Dialect/Torch/refine-types-ops.mlir

@@ -163,6 +163,22 @@ func.func @torch.aten.cat(%t0: !torch.tensor<[?,1,4], f32>, %t1: !torch.tensor<[
   return %ret : !torch.tensor
 }
 
+// -----
+// CHECK-LABEL:   func.func @torch.aten.cat$promote_type(
+// CHECK-SAME:                                 %[[T1:.*]]: !torch.tensor<[2,1,4],i1>,
+// CHECK-SAME:                                 %[[T2:.*]]: !torch.tensor<[2,3,4],si64>) -> !torch.tensor {
+// CHECK:           %[[INT1:.*]] = torch.constant.int 1
+// CHECK:           %[[TENSORS:.*]] = torch.prim.ListConstruct %[[T1]], %[[T2]] : (!torch.tensor<[2,1,4],i1>, !torch.tensor<[2,3,4],si64>) -> !torch.list<tensor>
+// CHECK:           %[[RET:.*]] = torch.aten.cat %[[TENSORS]], %[[INT1]] : !torch.list<tensor>, !torch.int -> !torch.tensor<*,si64>
+// CHECK:           %[[CAST:.*]] = torch.tensor_static_info_cast %[[RET]] : !torch.tensor<*,si64> to !torch.tensor
+// CHECK:           return %[[CAST]] : !torch.tensor
+func.func @torch.aten.cat$promote_type(%t0: !torch.tensor<[2,1,4], i1>, %t1: !torch.tensor<[2,3,4], si64>) -> !torch.tensor {
+  %int1 = torch.constant.int 1
+  %tensorList = torch.prim.ListConstruct %t0, %t1: (!torch.tensor<[2,1,4], i1>, !torch.tensor<[2,3,4], si64>) -> !torch.list<tensor>
+  %ret = torch.aten.cat %tensorList, %int1 : !torch.list<tensor>, !torch.int -> !torch.tensor
+  return %ret : !torch.tensor
+}
+
 // -----
 // CHECK-LABEL:   func.func @torch.aten._shape_as_tensor(
 // CHECK-SAME:                                 %[[INPUT:.*]]: !torch.tensor<[?,1,4],f32>) -> !torch.tensor {