Replace std::map.at() with std::map[].


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86102 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AggressiveAntiDepBreaker.cpp b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
index 416d674..86d051c 100644
--- a/lib/CodeGen/AggressiveAntiDepBreaker.cpp
+++ b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
@@ -568,7 +568,7 @@
 
   DEBUG(errs() << "\tFind Register:");
 
-  const TargetRegisterClass::iterator OrigR = RenameOrder.at(SuperRC);
+  const TargetRegisterClass::iterator OrigR = RenameOrder[SuperRC];
   const TargetRegisterClass::iterator EndR = ((OrigR == RE) ? RB : OrigR);
   TargetRegisterClass::iterator R = OrigR;
   do {