diff --git a/mlir/lib/Transforms/Utils/LoopUtils.cpp b/mlir/lib/Transforms/Utils/LoopUtils.cpp
--- a/mlir/lib/Transforms/Utils/LoopUtils.cpp
+++ b/mlir/lib/Transforms/Utils/LoopUtils.cpp
@@ -1160,8 +1160,10 @@
     function_ref<void(unsigned, Operation *, OpBuilder)> annotateFn) {
   assert(unrollFactor > 0 && "unroll factor should be positive");
 
-  if (unrollFactor == 1)
-    return promoteIfSingleIteration(forOp);
+  if (unrollFactor == 1) {
+    (void)promoteIfSingleIteration(forOp);
+    return success();
+  }
 
   // Nothing in the loop body other than the terminator.
   if (llvm::hasSingleElement(forOp.getBody()->getOperations()))
@@ -1215,8 +1217,10 @@
     scf::ForOp forOp, uint64_t unrollFactor,
     function_ref<void(unsigned, Operation *, OpBuilder)> annotateFn) {
   assert(unrollFactor > 0 && "expected positive unroll factor");
-  if (unrollFactor == 1)
-    return promoteIfSingleIteration(forOp);
+  if (unrollFactor == 1) {
+    (void)promoteIfSingleIteration(forOp);
+    return success();
+  }
 
   // Return if the loop body is empty.
   if (llvm::hasSingleElement(forOp.getBody()->getOperations()))
@@ -1383,8 +1387,10 @@
                                           uint64_t unrollJamFactor) {
   assert(unrollJamFactor > 0 && "unroll jam factor should be positive");
 
-  if (unrollJamFactor == 1)
-    return promoteIfSingleIteration(forOp);
+  if (unrollJamFactor == 1) {
+    (void)promoteIfSingleIteration(forOp);
+    return success();
+  }
 
   // Nothing in the loop body other than the terminator.
   if (llvm::hasSingleElement(forOp.getBody()->getOperations()))