Update LLVM for rebase to r212749.

Includes a cherry-pick of:
r212948 - fixes a small issue with atomic calls

Change-Id: Ib97bd980b59f18142a69506400911a6009d9df18
diff --git a/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp b/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
index 2212941..6a5c431 100644
--- a/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
+++ b/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
@@ -308,7 +308,7 @@
     return;
 
   const Function *GV = MF->getFunction();
-  assert(FnDebugInfo.count(GV) == true);
+  assert(FnDebugInfo.count(GV));
   assert(CurFn == &FnDebugInfo[GV]);
 
   if (CurFn->Instrs.empty()) {