Silence a bunch (but not all) "variable written but not read" warnings

when building with assertions disabled.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137460 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/RegisterScavenging.cpp

@@ -206,6 +206,7 @@ void RegScavenger::forward() {
             break;
           }
         assert(SubUsed && "Using an undefined register!");
+        (void)SubUsed;
       }
       assert((!EarlyClobberRegs.test(Reg) || MI->isRegTiedToDefOperand(i)) &&
              "Using an early clobbered register!");