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/IR/Instruction.cpp b/lib/IR/Instruction.cpp
index 28cc4cb..86421c4 100644
--- a/lib/IR/Instruction.cpp
+++ b/lib/IR/Instruction.cpp
@@ -145,31 +145,31 @@
 
 /// Determine whether the unsafe-algebra flag is set.
 bool Instruction::hasUnsafeAlgebra() const {
-  assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
+  assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
   return cast<FPMathOperator>(this)->hasUnsafeAlgebra();
 }
 
 /// Determine whether the no-NaNs flag is set.
 bool Instruction::hasNoNaNs() const {
-  assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
+  assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
   return cast<FPMathOperator>(this)->hasNoNaNs();
 }
 
 /// Determine whether the no-infs flag is set.
 bool Instruction::hasNoInfs() const {
-  assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
+  assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
   return cast<FPMathOperator>(this)->hasNoInfs();
 }
 
 /// Determine whether the no-signed-zeros flag is set.
 bool Instruction::hasNoSignedZeros() const {
-  assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
+  assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
   return cast<FPMathOperator>(this)->hasNoSignedZeros();
 }
 
 /// Determine whether the allow-reciprocal flag is set.
 bool Instruction::hasAllowReciprocal() const {
-  assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
+  assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
   return cast<FPMathOperator>(this)->hasAllowReciprocal();
 }
 
@@ -177,7 +177,7 @@
 /// operator which supports these flags. See LangRef.html for the meaning of
 /// these flats.
 FastMathFlags Instruction::getFastMathFlags() const {
-  assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
+  assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
   return cast<FPMathOperator>(this)->getFastMathFlags();
 }
 
@@ -300,6 +300,7 @@
            FI->getSynchScope() == cast<FenceInst>(I2)->getSynchScope();
   if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(I1))
     return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I2)->isVolatile() &&
+           CXI->isWeak() == cast<AtomicCmpXchgInst>(I2)->isWeak() &&
            CXI->getSuccessOrdering() ==
                cast<AtomicCmpXchgInst>(I2)->getSuccessOrdering() &&
            CXI->getFailureOrdering() ==
@@ -331,6 +332,10 @@
       getType() != I->getType())
     return false;
 
+  // If both instructions have no operands, they are identical.
+  if (getNumOperands() == 0 && I->getNumOperands() == 0)
+    return haveSameSpecialState(this, I);
+
   // We have two instructions of identical opcode and #operands.  Check to see
   // if all operands are the same.
   if (!std::equal(op_begin(), op_end(), I->op_begin()))