Fix unused variable warnings

Differential Revision: https://reviews.llvm.org/D35280

llvm-svn: 307740
diff --git a/llvm/lib/IR/LLVMContext.cpp b/llvm/lib/IR/LLVMContext.cpp
index 1463cdb..c58459d 100644
--- a/llvm/lib/IR/LLVMContext.cpp
+++ b/llvm/lib/IR/LLVMContext.cpp
@@ -86,11 +86,13 @@
       pImpl->getOrInsertSyncScopeID("singlethread");
   assert(SingleThreadSSID == SyncScope::SingleThread &&
          "singlethread synchronization scope ID drifted!");
+  (void)SingleThreadSSID;
 
   SyncScope::ID SystemSSID =
       pImpl->getOrInsertSyncScopeID("");
   assert(SystemSSID == SyncScope::System &&
          "system synchronization scope ID drifted!");
+  (void)SystemSSID;
 }
 
 LLVMContext::~LLVMContext() { delete pImpl; }