Change std::{lower,upper}_bound to llvm::{lower,upper}_bound or llvm::partition_point. NFC

llvm-svn: 365006
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 3b149e6..0e5881e3 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -1041,9 +1041,8 @@
 
         // Find the smallest value >= the lower bound.  If I is in the
         // case range, then we have overlap.
-        CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
-                                                  CaseVals.end(), CRLo,
-                                                  CaseCompareFunctor());
+        CaseValsTy::iterator I =
+            llvm::lower_bound(CaseVals, CRLo, CaseCompareFunctor());
         if (I != CaseVals.end() && I->first < CRHi) {
           OverlapVal  = I->first;   // Found overlap with scalar.
           OverlapStmt = I->second;