[TORCH][MLIR] Fix the return types of `aten.native_layer_norm`.

This commit fixes the 2nd and 3rd return types of the `aten.native_layer_norm`.
Previously the mean and rSTD were returned with reduction dims removed.
This commit fixes this and keeps the reduction dims of the results.

Signed-Off-By: Prateek Gupta <prateek@nord-labs.com>

e2e_testing/torchscript/norm_like.py

@@ -204,15 +204,35 @@ class NativeLayerNormModule(torch.nn.Module):
     ])
     def forward(self, x, weight, bias):
         list = [2, 2, 3]
-        # TODO: Fix the case of the other return values.
         return torch.ops.aten.native_layer_norm(
-            x, list, weight, bias, eps=0.5)[0]
+            x, list, weight, bias, eps=0.5)
 
 
 @register_test_case(module_factory=lambda: NativeLayerNormModule())
 def NativeLayerNormModule_basic(module, tu: TestUtils):
     module.forward(tu.rand(2, 5, 2, 2, 3), tu.rand(2, 2, 3), tu.rand(2, 2, 3))
 
+class NativeLayerNormDynamicModule(torch.nn.Module):
+    def __init__(self):
+        super().__init__()
+
+    @export
+    @annotate_args([
+        None,
+        ([-1, -1, -1, -1, -1], torch.float32, True),
+        ([-1, -1, -1], torch.float32, True),
+        ([-1, -1, -1], torch.float32, True),
+    ])
+    def forward(self, x, weight, bias):
+        list = [2, 2, 3]
+        return torch.ops.aten.native_layer_norm(
+            x, list, weight, bias, eps=0.5)
+
+
+@register_test_case(module_factory=lambda: NativeLayerNormDynamicModule())
+def NativeLayerNormDynamicModule_basic(module, tu: TestUtils):
+    module.forward(tu.rand(2, 5, 2, 2, 3), tu.rand(2, 2, 3), tu.rand(2, 2, 3))
+
 # ==============================================================================
 
 class NativeLayerNormModule4D(torch.nn.Module):

lib/Conversion/TorchToLinalg/Uncategorized.cpp

@@ -1009,22 +1009,37 @@ public:
 };
 } // namespace
 
-// Normalization formula:
+/// Inverted STD: rSTD = 1 / sqrt(var + eps).
-//   ((input - mean) / sqrt(var + eps)) * weight + bias
+static Value calculateRSTD(OpBuilder &b, Location loc, Type elemTy, Value eps,
-static Value createLinalgPayloadCalculationForNormOps(
+                           Value var) {
-    OpBuilder &b, Location loc, Type elemTy, Value input, Value mean, Value var,
-    Value eps, Value weight, Value bias) {
-  Value inputSubMean = b.create<arith::SubFOp>(loc, input, mean);
   // The eps is always f64.
   Value truncatedEps = b.create<arith::TruncFOp>(loc, elemTy, eps);
   Value varPlusEps = b.create<arith::AddFOp>(loc, var, truncatedEps);
   Value rSTD = b.create<math::RsqrtOp>(loc, varPlusEps);
+  return rSTD;
+}
+
+// Normalization formula:
+//   ((input - mean) * rSTD * weight + bias
+static Value createLinalgPayloadCalculationForNormOpsWithRSTD(
+    OpBuilder &b, Location loc, Type elemTy, Value input, Value mean,
+    Value rSTD, Value eps, Value weight, Value bias) {
+  Value inputSubMean = b.create<arith::SubFOp>(loc, input, mean);
   Value temp = b.create<arith::MulFOp>(loc, inputSubMean, rSTD);
   Value timesWeight = b.create<arith::MulFOp>(loc, temp, weight);
   Value plusBias = b.create<arith::AddFOp>(loc, timesWeight, bias);
   return plusBias;
 }
 
+static Value createLinalgPayloadCalculationForNormOpsWithVar(
+    OpBuilder &b, Location loc, Type elemTy, Value input, Value mean, Value var,
+    Value eps, Value weight, Value bias) {
+  Value rSTD = calculateRSTD(b, loc, elemTy, eps, var);
+  Value result = createLinalgPayloadCalculationForNormOpsWithRSTD(
+      b, loc, elemTy, input, mean, rSTD, eps, weight, bias);
+  return result;
+}
+
 namespace {
 class ConvertAtenBatchNormOp : public OpConversionPattern<AtenBatchNormOp> {
 public:
@@ -1117,9 +1132,10 @@ public:
                 [&](OpBuilder &b, Location loc, ValueRange args) {
                   Value input = args[0], weight = args[1], bias = args[2],
                         mean = args[3], var = args[4];
-                  Value result = createLinalgPayloadCalculationForNormOps(
+                  Value result =
-                      b, loc, var.getType(), input, mean, var, eps, weight,
+                      createLinalgPayloadCalculationForNormOpsWithVar(
-                      bias);
+                          b, loc, var.getType(), input, mean, var, eps, weight,
+                          bias);
                   b.create<linalg::YieldOp>(loc, result);
                 })
             .getResult(0);
@@ -1139,13 +1155,12 @@ public:
 // |  meanAndVarShape  |   normalizedShape  |
 // +-------------------+---------------------
 // <------------+ inputShape +-------------->
-
 // There are the following steps:
 // Step 1. Check if all the arguments meet the requirements.
 // Step 2. Common parts to be used for getting mean and var.
 //         This includes elements count, affineMap and iteratorTypes.
 // Step 3. Get mean.
-// Step 4. Get var.
+// Step 4. Get rSTD.
 // Step 5. Get layernorm.
 namespace {
 class ConvertAtenNativeLayerNormOp
@@ -1283,7 +1298,7 @@ public:
                     .getResult(0);
     Value mean = genMeanOrVarCalculation(sum);
 
-    // Step 4. Get var.
+    // Step 4. Get rSTD.
 
     // Calculate squareSum for the layer.
     SmallVector<AffineMap> squareSumIndexingMaps{
@@ -1310,6 +1325,21 @@ public:
                 })
             .getResult(0);
     Value var = genMeanOrVarCalculation(squareSum);
+    Value rSTDTensor = rewriter.create<linalg::InitTensorOp>(
+        loc, meanAndVarShapeSizes, elemTy);
+    SmallVector<AffineMap> rSTDIndexingMap(
+        2, rewriter.getMultiDimIdentityMap(meanAndVarShapeRank));
+
+    Value rSTD = rewriter
+                     .create<linalg::GenericOp>(
+                         loc, rSTDTensor.getType(), var, rSTDTensor,
+                         rSTDIndexingMap, meanAndVarIterationTypes,
+                         [&](OpBuilder &b, Location loc, ValueRange args) {
+                           Value result =
+                               calculateRSTD(b, loc, elemTy, eps, args[0]);
+                           b.create<linalg::YieldOp>(loc, result);
+                         })
+                     .getResult(0);
 
     // Step 5. Get layernorm.
 
@@ -1320,7 +1350,6 @@ public:
     auto normalizedShapeAffineMap = AffineMap::get(
         /*dimCount=*/inputRank,
         /*symbolCount=*/0, normalizedShapeExprs, context);
-
     auto inputSizes = getTensorSizes(rewriter, loc, input);
     Value initLayerNormTensor =
         rewriter.create<linalg::InitTensorOp>(loc, inputSizes, elemTy);
@@ -1334,24 +1363,48 @@ public:
         rewriter
             .create<linalg::GenericOp>(
                 loc, initLayerNormTensor.getType(),
-                ValueRange{input, mean, var, weight, bias}, initLayerNormTensor,
+                ValueRange{input, mean, rSTD, weight, bias},
+                initLayerNormTensor,
                 /*indexingMaps=*/indexingMaps,
                 /*iteratorTypes=*/layerNormIterationTypes,
                 [&](OpBuilder &b, Location loc, ValueRange args) {
-                  Value input = args[0], mean = args[1], var = args[2],
+                  Value input = args[0], mean = args[1], rSTD = args[2],
                         weight = args[3], bias = args[4];
-                  Value result = createLinalgPayloadCalculationForNormOps(
+                  Value result =
-                      b, loc, elemTy, input, mean, var, eps, weight, bias);
+                      createLinalgPayloadCalculationForNormOpsWithRSTD(
+                          b, loc, elemTy, input, mean, rSTD, eps, weight, bias);
                   b.create<linalg::YieldOp>(loc, result);
                 })
             .getResult(0);
+    SmallVector<int64_t> expandShape(inputRank, 1);
+    for (int i = 0; i < meanAndVarShapeRank; i++) {
+      // `mean` and `rstd` are not yet casted, so they will be having dynamic
+      // shape. Hence to match them, for each dimension corresponding to `mean`
+      // or `rstd` assign -1.
+      expandShape[i] = -1;
+    }
+    auto expandShapeType = RankedTensorType::get(expandShape, elemTy);
+    SmallVector<ReassociationIndices> reassociation(meanAndVarShapeRank);
+    for (auto i : llvm::seq<int64_t>(0, meanAndVarShapeRank)) {
+      reassociation[i].push_back(i);
+      if (i == meanAndVarShapeRank - 1) {
+        for (auto j : llvm::seq<int64_t>(0, normalizedShapeRank))
+          reassociation[i].push_back(i + j + 1);
+      }
+    }
+    Value meanResult = rewriter.create<tensor::ExpandShapeOp>(
+        loc, expandShapeType, mean, reassociation);
+    Value rSTDResult = rewriter.create<tensor::ExpandShapeOp>(
+        loc, expandShapeType, rSTD, reassociation);
     Type layerNormResultType = getTypeConverter()->convertType(op.getType(0));
     Type meanResultType = getTypeConverter()->convertType(op.getType(1));
-    Type varResultType = getTypeConverter()->convertType(op.getType(2));
+    Type rSTDResultType = getTypeConverter()->convertType(op.getType(2));
     Value layerNorm_ =
         rewriter.create<tensor::CastOp>(loc, layerNormResultType, layerNorm);
-    Value mean_ = rewriter.create<tensor::CastOp>(loc, meanResultType, mean);
+    Value mean_ =
-    Value var_ = rewriter.create<tensor::CastOp>(loc, varResultType, var);
+        rewriter.create<tensor::CastOp>(loc, meanResultType, meanResult);
+    Value var_ =
+        rewriter.create<tensor::CastOp>(loc, rSTDResultType, rSTDResult);
     rewriter.replaceOp(op, {layerNorm_, mean_, var_});
     return success();
   }

lib/Dialect/Torch/Transforms/DecomposeComplexOps.cpp

@@ -1118,9 +1118,10 @@ class DecomposeAtenLayerNormOp : public OpRewritePattern<AtenLayerNormOp> {
     Value normalizedShape = op.normalized_shape();
     SmallVector<Value> normalizedShapeSizesTorchInt;
     getListConstructElements(normalizedShape, normalizedShapeSizesTorchInt);
-    std::vector<int64_t> meanVarSizes;
+    int64_t axis = inputRank - normalizedShapeSizesTorchInt.size();
-    for (int i = normalizedShapeSizesTorchInt.size(); i < inputRank; i++)
+    std::vector<int64_t> meanVarSizes(inputRank, 1);
-      meanVarSizes.push_back(input.getSizes()[i]);
+    for (int i = 0; i < axis; i++)
+      meanVarSizes[i] = input.getSizes()[i];
     auto meanVarType = input.getWithSizesAndDtype(
         llvm::makeArrayRef(meanVarSizes), input.getDtype());
     auto nativeLayerNorm = rewriter.create<AtenNativeLayerNormOp>(

lib/Dialect/Torch/Transforms/ShapeLibrary.cpp

@@ -2513,20 +2513,36 @@ module {
   }
   func @"__torch_mlir_shape_fn.aten.native_layer_norm"(%arg0: !torch.list<int>, %arg1: !torch.list<int>, %arg2: !torch.optional<list<int>>, %arg3: !torch.optional<list<int>>, %arg4: !torch.float) -> !torch.tuple<list<int>, list<int>, list<int>> {
     %int1 = torch.constant.int 1
+    %int0 = torch.constant.int 0
+    %str = torch.constant.str "AssertionError: "
+    %none = torch.constant.none
     %true = torch.constant.bool true
     %0 = torch.prim.ListConstruct  : () -> !torch.list<int>
-    %1 = torch.aten.len.t %arg1 : !torch.list<int> -> !torch.int
+    %1 = torch.aten.len.t %arg0 : !torch.list<int> -> !torch.int
-    %2 = torch.aten.len.t %arg0 : !torch.list<int> -> !torch.int
+    %2 = torch.aten.len.t %arg1 : !torch.list<int> -> !torch.int
-    %3 = torch.aten.__range_length %1, %2, %int1 : !torch.int, !torch.int, !torch.int -> !torch.int
+    %3 = torch.aten.sub.int %1, %2 : !torch.int, !torch.int -> !torch.int
+    %4 = torch.aten.ge.int %3, %int0 : !torch.int, !torch.int -> !torch.bool
+    torch.prim.If %4 -> () {
+      torch.prim.If.yield
+    } else {
+      torch.prim.RaiseException %str, %none : !torch.str, !torch.none
+      torch.prim.If.yield
+    }
     torch.prim.Loop %3, %true, init() {
     ^bb0(%arg5: !torch.int):
-      %5 = torch.aten.__derive_index %arg5, %1, %int1 : !torch.int, !torch.int, !torch.int -> !torch.int
+      %8 = torch.aten.__getitem__.t %arg0, %arg5 : !torch.list<int>, !torch.int -> !torch.int
-      %6 = torch.aten.__getitem__.t %arg0, %5 : !torch.list<int>, !torch.int -> !torch.int
+      %9 = torch.aten.append.t %0, %8 : !torch.list<int>, !torch.int -> !torch.list<int>
-      %7 = torch.aten.append.t %0, %6 : !torch.list<int>, !torch.int -> !torch.list<int>
       torch.prim.Loop.condition %true, iter()
     } : (!torch.int, !torch.bool) -> ()
-    %4 = torch.prim.TupleConstruct %arg0, %0, %0 : !torch.list<int>, !torch.list<int>, !torch.list<int> -> !torch.tuple<list<int>, list<int>, list<int>>
+    %5 = torch.aten.len.t %arg0 : !torch.list<int> -> !torch.int
-    return %4 : !torch.tuple<list<int>, list<int>, list<int>>
+    %6 = torch.aten.__range_length %3, %5, %int1 : !torch.int, !torch.int, !torch.int -> !torch.int
+    torch.prim.Loop %6, %true, init() {
+    ^bb0(%arg5: !torch.int):
+      %8 = torch.aten.append.t %0, %int1 : !torch.list<int>, !torch.int -> !torch.list<int>
+      torch.prim.Loop.condition %true, iter()
+    } : (!torch.int, !torch.bool) -> ()
+    %7 = torch.prim.TupleConstruct %arg0, %0, %0 : !torch.list<int>, !torch.list<int>, !torch.list<int> -> !torch.tuple<list<int>, list<int>, list<int>>
+    return %7 : !torch.tuple<list<int>, list<int>, list<int>>
   }
   func @"__torch_mlir_shape_fn.aten.native_batch_norm"(%arg0: !torch.list<int>, %arg1: !torch.optional<list<int>>, %arg2: !torch.optional<list<int>>, %arg3: !torch.optional<list<int>>, %arg4: !torch.optional<list<int>>, %arg5: !torch.bool, %arg6: !torch.float, %arg7: !torch.float) -> !torch.tuple<list<int>, list<int>, list<int>> {
     %int0 = torch.constant.int 0

python/torch_mlir/dialects/torch/importer/jit_ir/build_tools/shape_lib_gen.py

@@ -773,25 +773,17 @@ def aten〇nll_loss_forward(self: List[int], target: List[int], weight: Optional
 def aten〇nll_loss_backward(grad_output: List[int], self: List[int], target: List[int], weight: Optional[List[int]], reduction: int, ignore_index: int, total_weight: List[int]) -> List[int]:
     return upstream_shape_helpers.unary(self)
 
-# TODO: Fix shape function (see body).
+@check_shape_function([
-# @check_shape_function([
+    Invocation(TensorOfShape(2, 5, 2, 2, 3), [2, 2, 3], None, None, 1e-6), # Basic case.
-#     Invocation(TensorOfShape(2, 5, 2, 2, 3), [2, 2, 3], None, None, 1e-6), # Basic case.
+])
-# ])
 def aten〇native_layer_norm(input: List[int], normalized_shape: List[int], weight: Optional[List[int]], bias: Optional[List[int]], eps: float) -> Tuple[List[int], List[int], List[int]]:
     reduction_shape: List[int] = []
-    # TODO: Fix buggy behavior. TorchToLinalg needs to properly handle the
+    num_unreduced_dimensions = len(input) - len(normalized_shape)
-    # correctly inferred shapes.
+    assert num_unreduced_dimensions >= 0
-    # With input=[2, 5, 2, 2, 3] and normalized_shape=[2, 2, 3], we should get
+    for i in range(num_unreduced_dimensions):
-    # [[2, 5, 2, 2, 3], [2, 5, 1, 1, 1], [2, 5, 1, 1, 1]]
-    for i in range(len(normalized_shape), len(input)):
         reduction_shape.append(input[i])
-    # Correct code:
+    for i in range(num_unreduced_dimensions, len(input)):
-    # num_unreduced_dimensions = len(input) - len(normalized_shape)
+        reduction_shape.append(1)
-    # assert num_unreduced_dimensions >= 0
-    # for i in range(num_unreduced_dimensions):
-    #     reduction_shape.append(input[i])
-    # for i in range(num_unreduced_dimensions, len(input)):
-    #     reduction_shape.append(1)
     return input, reduction_shape, reduction_shape
 
 @check_shape_function([