Assert that region is not cloned into itself.

PiperOrigin-RevId: 273707291

diff --git a/mlir/lib/IR/Region.cpp b/mlir/lib/IR/Region.cpp
index 2d9f62c..4e408f2 100644 (file)
--- a/mlir/lib/IR/Region.cpp
+++ b/mlir/lib/IR/Region.cpp
@@ -78,6 +78,7 @@ void Region::cloneInto(Region *dest, BlockAndValueMapping &mapper) {
 void Region::cloneInto(Region *dest, Region::iterator destPos,
                        BlockAndValueMapping &mapper) {
   assert(dest && "expected valid region to clone into");
+  assert(this != dest && "cannot clone region into itself");
 
   // If the list is empty there is nothing to clone.
   if (empty())