Use do+while instead of while for loops which obviously have a

non-zero trip count. Use SmallVector's pop_back_val().


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92734 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/SCCVN.cpp

@@ -678,8 +678,7 @@ bool SCCVN::runOnFunction(Function& F) {
           stack.push_back(*PI);
       
       while (!stack.empty()) {
-        BasicBlock* CurrBB = stack.back();
-        stack.pop_back();
+        BasicBlock* CurrBB = stack.pop_back_val();
         visited.insert(CurrBB);
         
         ValueNumberScope* S = BBMap[CurrBB];