[circle-mlir] Add pass for Sign operation

This introduces the sign operation pass.

ONE-DCO-1.0-Signed-off-by: Seungho Henry Park <shs.park@samsung.com>

Author: shs-park

circle-mlir/circle-mlir/lib/pass/src/ConvertONNXToCirclePass.cpp

@@ -76,6 +76,7 @@
 #include "ops/ResizeOp.h"
 #include "ops/ShapeOp.h"
 #include "ops/SigmoidOp.h"
+#include "ops/SignOp.h"
 #include "ops/SinOp.h"
 #include "ops/SliceOp.h"
 #include "ops/SoftmaxOp.h"
@@ -265,6 +266,7 @@ void ConvertONNXToCirclePass::runOnOperation()
   patterns.insert<ConvResizeV13>(typeConverter, context);
   patterns.insert<ConvShape>(typeConverter, context);
   patterns.insert<ConvSigmoid>(typeConverter, context);
+  patterns.insert<ConvSign>(typeConverter, context);
   patterns.insert<ConvSin>(typeConverter, context);
   patterns.insert<ConvSlice>(typeConverter, context);
   patterns.insert<ConvSoftmax>(typeConverter, context);

circle-mlir/circle-mlir/lib/pass/src/ops/SignOp.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2026 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __CIRCLE_MLIR_PASS_OPS_SIGN_OP_H__
+#define __CIRCLE_MLIR_PASS_OPS_SIGN_OP_H__
+
+#include <circle-mlir/dialect/CircleDialect.h>
+
+#include "ConvertHelper.h"
+
+#include <mlir/Transforms/DialectConversion.h>
+
+#include <src/Dialect/ONNX/ONNXOps.hpp>
+
+namespace mlir
+{
+namespace Circle
+{
+
+class ConvSign : public mlir::OpConversionPattern<mlir::ONNXSignOp>
+{
+public:
+  using mlir::OpConversionPattern<mlir::ONNXSignOp>::OpConversionPattern;
+  using OpAdaptor = typename mlir::ONNXSignOp::Adaptor;
+
+  mlir::LogicalResult matchAndRewrite(mlir::ONNXSignOp op, OpAdaptor adaptor,
+                                      mlir::ConversionPatternRewriter &rewriter) const override
+  {
+    mlir::Value input = adaptor.getInput();
+
+    rewriter.replaceOpWithNewOp<SignOp>(op, op.getType(), input);
+
+    return mlir::success();
+  }
+};
+
+} // namespace Circle
+} // namespace mlir
+
+#endif // __CIRCLE_MLIR_PASS_OPS_SIGN_OP_H__