Use pop_back_val() instead of both back() and pop_back().

llvm-svn: 188723

Author: Jakub Staszak

llvm/lib/Transforms/InstCombine/InstCombineWorklist.h

@@ -74,8 +74,7 @@ class LLVM_LIBRARY_VISIBILITY InstCombineWorklist {
   }
 
   Instruction *RemoveOne() {
-    Instruction *I = Worklist.back();
-    Worklist.pop_back();
+    Instruction *I = Worklist.pop_back_val();
     WorklistMap.erase(I);
     return I;
   }