diff --git a/mlir/include/mlir/Dialect/Shape/IR/ShapeOps.td b/mlir/include/mlir/Dialect/Shape/IR/ShapeOps.td
--- a/mlir/include/mlir/Dialect/Shape/IR/ShapeOps.td
+++ b/mlir/include/mlir/Dialect/Shape/IR/ShapeOps.td
@@ -130,6 +130,10 @@
   let arguments = (ins IndexAttr:$value);
   let results = (outs Shape_SizeType:$result);
 
+  let builders = [
+    OpBuilder<"OpBuilder &builder, OperationState &result, int64_t value">
+  ];
+
   let assemblyFormat = "$value attr-dict";
   let hasFolder = 1;
 }
@@ -181,6 +185,7 @@
   let assemblyFormat = "attr-dict $shape";
 
   let hasFolder = 1;
+  let hasCanonicalizer = 1;
 }
 
 def Shape_ToExtentTensorOp : Shape_Op<"to_extent_tensor", [NoSideEffect]> {
diff --git a/mlir/lib/Dialect/Shape/IR/Shape.cpp b/mlir/lib/Dialect/Shape/IR/Shape.cpp
--- a/mlir/lib/Dialect/Shape/IR/Shape.cpp
+++ b/mlir/lib/Dialect/Shape/IR/Shape.cpp
@@ -359,6 +359,12 @@
 // ConstSizeOp
 //===----------------------------------------------------------------------===//
 
+void ConstSizeOp::build(OpBuilder &builder, OperationState &result,
+                        int64_t value) {
+  auto attr = builder.getIndexAttr(value);
+  build(builder, result, attr);
+}
+
 OpFoldResult ConstSizeOp::fold(ArrayRef<Attribute>) { return valueAttr(); }
 
 void ConstSizeOp::getAsmResultNames(
@@ -445,6 +451,32 @@
   return builder.getIndexAttr(size);
 }
 
+namespace {
+struct GetSizeShapeOfCanonicalizationPattern
+    : public OpRewritePattern<GetSizeOp> {
+  using OpRewritePattern<GetSizeOp>::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(GetSizeOp op,
+                                PatternRewriter &rewriter) const override {
+    auto shapeOfOp = dyn_cast_or_null<ShapeOfOp>(op.shape().getDefiningOp());
+    if (!shapeOfOp)
+      return failure();
+    auto rankedTensorType =
+        shapeOfOp.arg().getType().dyn_cast<RankedTensorType>();
+    if (!rankedTensorType)
+      return failure();
+    int64_t shapeSize = rankedTensorType.getRank();
+    rewriter.replaceOpWithNewOp<ConstSizeOp>(op.getOperation(), shapeSize);
+    return success();
+  }
+};
+} // namespace
+
+void GetSizeOp::getCanonicalizationPatterns(OwningRewritePatternList &patterns,
+                                            MLIRContext *context) {
+  patterns.insert<GetSizeShapeOfCanonicalizationPattern>(context);
+}
+
 //===----------------------------------------------------------------------===//
 // NumElementsOp
 //===----------------------------------------------------------------------===//
diff --git a/mlir/test/Dialect/Shape/canonicalize.mlir b/mlir/test/Dialect/Shape/canonicalize.mlir
--- a/mlir/test/Dialect/Shape/canonicalize.mlir
+++ b/mlir/test/Dialect/Shape/canonicalize.mlir
@@ -478,3 +478,29 @@
   %size = shape.get_size %shape
   return %size : !shape.size
 }
+
+// -----
+
+// Canonicalize `get_size` when shape is derived from ranked tensor.
+// CHECK-LABEL: @canonicalize_size
+func @canonicalize_size(%arg : tensor<1x2x?xf32>) -> !shape.size {
+// CHECK-DAG: %[[RESULT:.*]] = shape.const_size 3
+// CHECK-DAG: return %[[RESULT]] : !shape.size
+%shape = shape.shape_of %arg : tensor<1x2x?xf32>
+%size = shape.get_size %shape
+return %size : !shape.size
+}
+
+// -----
+
+// Do not canonicalize `get_size` when shape is derived from unranked tensor.
+// CHECK-LABEL: @dont_canonicalize_size
+// CHECK-SAME: (%[[ARG:.*]]: tensor<*xf32>) -> !shape.size
+func @dont_canonicalize_size(%arg : tensor<*xf32>) -> !shape.size {
+// CHECK-DAG: %[[SHAPE:.*]] = shape.shape_of %[[ARG]] : tensor<*xf32>
+// CHECK-DAG: %[[SIZE:.*]] = shape.get_size %[[SHAPE]]
+// CHECK-DAG: return %[[SIZE]] : !shape.size
+%shape = shape.shape_of %arg : tensor<*xf32>
+%size = shape.get_size %shape
+return %size : !shape.size
+}