Avoid warning of unused variable in release builds. NFC

llvm-svn: 302068
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index 2c8e6c0..391fde3 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -520,6 +520,8 @@
       (LatchBR->getSuccessor(0) == Exit || LatchBR->getSuccessor(1) == Exit) &&
       "one of the loop latch successors should be "
       "the exit block!");
+  // Avoid warning of unused `LatchBR` variable in release builds.
+  (void)LatchBR;
   // Loop structure is the following:
   //
   // PreHeader