diff --git a/third_party/subzero/src/IceUtils.h b/third_party/subzero/src/IceUtils.h
index 2c7c62b..e600cf1 100644
--- a/third_party/subzero/src/IceUtils.h
+++ b/third_party/subzero/src/IceUtils.h
@@ -134,7 +134,7 @@
   // Don't call reserve() if Size==0.
   if (Size > 0) {
     uint32_t Mask;
-    if (Size <= (1 << ChunkSizeBits)) {
+    if (Size <= (1u << ChunkSizeBits)) {
       // For smaller sizes, reserve the smallest power of 2 greater than or
       // equal to Size.
       Mask =