diff --git a/mlir/lib/Dialect/Shape/Transforms/CanonicalizeShapeToStandardPatterns.td b/mlir/lib/Dialect/Shape/Transforms/CanonicalizeShapeToStandardPatterns.td
--- a/mlir/lib/Dialect/Shape/Transforms/CanonicalizeShapeToStandardPatterns.td
+++ b/mlir/lib/Dialect/Shape/Transforms/CanonicalizeShapeToStandardPatterns.td
@@ -1,6 +1,16 @@
 include "mlir/Dialect/Shape/IR/ShapeOps.td"
 include "mlir/Dialect/StandardOps/IR/Ops.td"
 
+// Rewrite patterns.
+
 def GetExtentShapeOfConversion : Pat<
     (Shape_GetExtentOp (Shape_ShapeOfOp $arg), $idx),
     (Shape_IndexToSizeOp (DimOp $arg, (Shape_SizeToIndexOp $idx)))>;
+
+def GetExtentFromExtentTensorConversion : Pattern<
+    (Shape_GetExtentOp (Shape_FromExtentTensorOp $extents), $idx),
+    [
+      (Shape_SizeToIndexOp:$std_idx $idx),
+      (ExtractElementOp:$std_result $extents, (NativeCodeCall<"ValueRange({$0})"> $std_idx)),
+      (Shape_IndexToSizeOp $std_result)
+    ]>;
diff --git a/mlir/test/Dialect/Shape/canonicalize-shape-to-standard.mlir b/mlir/test/Dialect/Shape/canonicalize-shape-to-standard.mlir
--- a/mlir/test/Dialect/Shape/canonicalize-shape-to-standard.mlir
+++ b/mlir/test/Dialect/Shape/canonicalize-shape-to-standard.mlir
@@ -14,4 +14,18 @@
   return %result : !shape.size
 }
 
+// -----
 
+// Express `get_extent` as `std.extract_element` when it relies directly on the
+// outcome of a `from_extent_tensor` operation.
+// CHECK-LABEL: @get_extent
+// CHECK-SAME: (%[[EXTENTS:.*]]: tensor<?xindex>, %[[IDX:.*]]: !shape.size) -> !shape.size
+func @get_extent(%extents : tensor<?xindex>, %idx : !shape.size) -> !shape.size {
+  // CHECK-DAG: %[[STD_IDX:.*]] = shape.size_to_index %[[IDX]]
+  // CHECK-DAG: %[[STD_RESULT:.*]] = extract_element %[[EXTENTS]][%[[STD_IDX]]] : tensor<?xindex>
+  // CHECK-DAG: %[[RESULT:.*]] = shape.index_to_size %[[STD_RESULT]]
+  // CHECK-DAG: return %[[RESULT]] : !shape.size
+  %shape = shape.from_extent_tensor %extents: tensor<?xindex>
+  %result = shape.get_extent %shape, %idx
+  return %result : !shape.size
+}