diff --git a/mlir/include/mlir/Transforms/GreedyPatternRewriteDriver.h b/mlir/include/mlir/Transforms/GreedyPatternRewriteDriver.h
--- a/mlir/include/mlir/Transforms/GreedyPatternRewriteDriver.h
+++ b/mlir/include/mlir/Transforms/GreedyPatternRewriteDriver.h
@@ -48,9 +48,9 @@
 // applyPatternsGreedily
 //===----------------------------------------------------------------------===//
 
-/// Rewrite the regions of the specified operation, which must be isolated from
-/// above, by repeatedly applying the highest benefit patterns in a greedy
-/// work-list driven manner.
+/// Rewrite the regions of the specified operation by repeatedly applying the
+/// highest benefit patterns in a greedy work-list driven manner. Only ops that
+/// are inside one of given regions are added to the work-list.
 ///
 /// This variant may stop after a predefined number of iterations, see the
 /// alternative below to provide a specific number of iterations before stopping
@@ -68,7 +68,7 @@
     MutableArrayRef<Region> regions, const FrozenRewritePatternSet &patterns,
     GreedyRewriteConfig config = GreedyRewriteConfig());
 
-/// Rewrite the given regions, which must be isolated from above.
+/// Rewrite the given regions.
 inline LogicalResult applyPatternsAndFoldGreedily(
     Operation *op, const FrozenRewritePatternSet &patterns,
     GreedyRewriteConfig config = GreedyRewriteConfig()) {
diff --git a/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp b/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
--- a/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
+++ b/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
@@ -432,11 +432,10 @@
   return failure();
 }
 
-/// Rewrite the regions of the specified operation, which must be isolated from
-/// above, by repeatedly applying the highest benefit patterns in a greedy
-/// work-list driven manner. Return success if no more patterns can be matched
-/// in the result operation regions. Note: This does not apply patterns to the
-/// top-level operation itself.
+/// Rewrite the regions of the specified operation by repeatedly applying the
+/// highest benefit patterns in a greedy work-list driven manner. Return success
+/// if no more patterns can be matched in the result operation regions.
+/// Note: This does not apply patterns to the top-level operation itself.
 ///
 LogicalResult
 mlir::applyPatternsAndFoldGreedily(MutableArrayRef<Region> regions,
@@ -445,16 +444,6 @@
   if (regions.empty())
     return success();
 
-  // The top-level operation must be known to be isolated from above to
-  // prevent performing canonicalizations on operations defined at or above
-  // the region containing 'op'.
-  auto regionIsIsolated = [](Region &region) {
-    return region.getParentOp()->hasTrait<OpTrait::IsIsolatedFromAbove>();
-  };
-  (void)regionIsIsolated;
-  assert(llvm::all_of(regions, regionIsIsolated) &&
-         "patterns can only be applied to operations IsolatedFromAbove");
-
   // Start the pattern driver.
   GreedyPatternRewriteDriver driver(regions[0].getContext(), patterns, config);
   bool converged = driver.simplify(regions);