Silence some release build warnings.

llvm-svn: 91234
diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index 0f201b5..b15b2e9 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -326,6 +326,7 @@
   llvm::BasicBlock *Unwind = 0;
 
   assert(PrevLandingPad == 0 && "EHSpec has invoke context");
+  (void)PrevLandingPad;
 
   llvm::BasicBlock *Cont = createBasicBlock("cont");