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/Analysis.cpp b/lib/CodeGen/Analysis.cpp
index 6fc83a2..1bdf312 100644
--- a/lib/CodeGen/Analysis.cpp
+++ b/lib/CodeGen/Analysis.cpp
@@ -7,13 +7,14 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file defines several CodeGen-specific LLVM IR analysis utilties.
+// This file defines several CodeGen-specific LLVM IR analysis utilities.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
@@ -474,8 +475,7 @@
 /// between it and the return.
 ///
 /// This function only tests target-independent requirements.
-bool llvm::isInTailCallPosition(ImmutableCallSite CS,
-                                const TargetLowering &TLI) {
+bool llvm::isInTailCallPosition(ImmutableCallSite CS, const SelectionDAG &DAG) {
   const Instruction *I = CS.getInstruction();
   const BasicBlock *ExitBB = I->getParent();
   const TerminatorInst *Term = ExitBB->getTerminator();
@@ -490,7 +490,7 @@
   // longjmp on x86), it can end up causing miscompilation that has not
   // been fully understood.
   if (!Ret &&
-      (!TLI.getTargetMachine().Options.GuaranteedTailCallOpt ||
+      (!DAG.getTarget().Options.GuaranteedTailCallOpt ||
        !isa<UnreachableInst>(Term)))
     return false;
 
@@ -509,7 +509,8 @@
         return false;
     }
 
-  return returnTypeIsEligibleForTailCall(ExitBB->getParent(), I, Ret, TLI);
+  return returnTypeIsEligibleForTailCall(ExitBB->getParent(), I, Ret,
+                                         *DAG.getTarget().getTargetLowering());
 }
 
 bool llvm::returnTypeIsEligibleForTailCall(const Function *F,