tcp.custom_op support for torch.aten.arange with dynamic input

lib/Conversion/TorchToTcp/TcpCustomOp.cpp

@@ -345,6 +345,50 @@ class ConvertAtenSliceScatterOp
   }
 };
 
+class ConvertAtenArangeStartStepOp
+    : public OpConversionPattern<AtenArangeStartStepOp> {
+  using OpConversionPattern::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(AtenArangeStartStepOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+
+    // At this point all tensors should have value semantics, and hence the
+    // `layout` check can be ignored.
+
+    // The pin_memory should be either `False` or `none`.
+    bool pinMemory;
+    if (!isa<Torch::NoneType>(op.getPinMemory().getType()) &&
+        (!matchPattern(op.getPinMemory(), m_TorchConstantBool(&pinMemory)) ||
+         pinMemory)) {
+      return rewriter.notifyMatchFailure(
+          op, "unimplemented: pin_memory must be either None or false");
+    }
+
+    torch_to_tcp::TorchToTcpCustomOpConversionHelper helper{op, rewriter,
+                                                            getTypeConverter()};
+    bool allStatic = true;
+    if (!helper.tryConvertConstToFloatAttr("start", op.getStart())) {
+      allStatic = false;
+      helper.addOperand("start", adaptor.getStart());
+    }
+    if (!helper.tryConvertConstToFloatAttr("end", op.getEnd())) {
+      allStatic = false;
+      helper.addOperand("end", adaptor.getEnd());
+    }
+    if (!helper.tryConvertConstToFloatAttr("step", op.getStep())) {
+      allStatic = false;
+      helper.addOperand("step", adaptor.getStep());
+    }
+    // static start, end, and step case will be handled through TOSA dialect
+    if (allStatic)
+      return rewriter.notifyMatchFailure(op,
+                                         "only non-constant values supported");
+
+    return helper.replace();
+  }
+};
+
 } // namespace
 
 void torch_to_tcp::populateTcpCustomOpPatternsAndLegality(
@@ -365,8 +409,10 @@ void torch_to_tcp::populateTcpCustomOpPatternsAndLegality(
   INSERT_ATEN_TO_TCP_CUSTOM_OP_PATTERN(AtenCumsumOp);
   INSERT_ATEN_TO_TCP_CUSTOM_OP_PATTERN(AtenMinDimOp);
   INSERT_ATEN_TO_TCP_CUSTOM_OP_PATTERN(AtenSliceScatterOp);
-  // AtenViewOp can still live after torch-to-tcp conversion
+  // Following ops can still live after torch-to-tcp conversion
   patterns.add<ConvertAtenViewOp>(typeConverter, patterns.getContext());
+  patterns.add<ConvertAtenArangeStartStepOp>(typeConverter,
+                                             patterns.getContext());
 #undef INSERT_ATEN_TO_TCP_CUSTOM_OP_PATTERN
 
   // Torch -> TOSA doesn't handle transposed convolutions; map them to

lib/Conversion/TorchToTcp/Utils.cpp

@@ -529,6 +529,29 @@ void TorchToTcpCustomOpConversionHelper::addFloatAttr(std::string attrName,
       rewriter.getNamedAttr(attrName, rewriter.getF64FloatAttr(constVal)));
 }
 
+bool TorchToTcpCustomOpConversionHelper::tryConvertConstToFloatAttr(
+    std::string attrName, Value value) {
+  if (conversionResult.failed())
+    return false;
+
+  double constFPVal;
+  if (matchPattern(value, torch::Torch::m_TorchConstantFloat(&constFPVal))) {
+    attrs.push_back(
+        rewriter.getNamedAttr(attrName, rewriter.getF64FloatAttr(constFPVal)));
+    return true;
+  }
+
+  // convert constant int to fp if possible
+  int64_t constIntVal;
+  if (matchPattern(value, torch::Torch::m_TorchConstantInt(&constIntVal))) {
+    attrs.push_back(rewriter.getNamedAttr(
+        attrName, rewriter.getF64FloatAttr(static_cast<double>(constIntVal))));
+    return true;
+  }
+
+  return false;
+}
+
 void TorchToTcpCustomOpConversionHelper::addListOfIntsAttr(std::string attrName,
                                                            Value value) {
   if (conversionResult.failed())

lib/Conversion/TorchToTcp/Utils.h

@@ -167,6 +167,9 @@ class TorchToTcpCustomOpConversionHelper {
   // Add value as a named float attribute
   void addFloatAttr(std::string attrName, Value value);
 
+  // Try to convert a const value to a float attribute.
+  bool tryConvertConstToFloatAttr(std::string attrName, Value value);
+
   // Add value as a named list of integers attribute
   void addListOfIntsAttr(std::string attrName, Value value);
 

test/Conversion/TorchToTcp/tcp_custom_ops.mlir

@@ -320,3 +320,22 @@ func.func @torch.aten.slice_scatter(%arg0: !torch.vtensor<[1,3],f32>, %arg1: !to
   %0 = torch.aten.slice_scatter %arg0, %arg1, %dim, %start, %end, %step : !torch.vtensor<[1,3],f32>, !torch.vtensor<[1,2],f32>, !torch.int, !torch.int, !torch.int, !torch.int -> !torch.vtensor<[1,3],f32>
   return %0 : !torch.vtensor<[1,3],f32>
 }
+
+// -----
+
+// CHECK-LABEL: func.func @torch.aten.arange.start_step(
+// CHECK-SAME:         %[[ARG0:.*]]: !torch.int) -> !torch.vtensor<[?],si32> {
+// CHECK: %[[IN:.*]] = torch_c.to_i64 %[[ARG0]]
+// CHECK: %[[OUT:.*]] = tcp.custom_op("torch.aten.arange.start_step") %[[IN]] {start = 0.000000e+00 : f64, step = 1.000000e+00 : f64, torch_operand_names = ["end"]} : i64 -> tensor<?xi32>
+// CHECK: %[[RET:.*]] = torch_c.from_builtin_tensor %[[OUT]] : tensor<?xi32> -> !torch.vtensor<[?],si32>
+// CHECK: return %[[RET]] : !torch.vtensor<[?],si32>
+func.func @torch.aten.arange.start_step(%arg0: !torch.int) -> !torch.vtensor<[?],si32> {
+  %false = torch.constant.bool false
+  %none = torch.constant.none
+  %cpu = torch.constant.device "cpu"
+  %int0 = torch.constant.int 0
+  %int1 = torch.constant.int 1
+  %int3 = torch.constant.int 3
+  %1 = torch.aten.arange.start_step %int0, %arg0, %int1, %int3, %none, %cpu, %false : !torch.int, !torch.int, !torch.int, !torch.int, !torch.none, !torch.Device, !torch.bool -> !torch.vtensor<[?],si32>
+  return %1 : !torch.vtensor<[?],si32>
+}