Rename invariant.group.barrier to launder.invariant.group

Summary:
This is one of the initial commit of "RFC: Devirtualization v2" proposal:
https://docs.google.com/document/d/16GVtCpzK8sIHNc2qZz6RN8amICNBtvjWUod2SujZVEo/edit?usp=sharing

Reviewers: rsmith, amharc, kuhar, sanjoy

Subscribers: arsenm, nhaehnle, javed.absar, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D45111

llvm-svn: 331448
diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 914dd18..8955d8a 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -1696,13 +1696,13 @@
   llvm::Type *elementTy = ConvertTypeForMem(allocType);
   Address result = Builder.CreateElementBitCast(allocation, elementTy);
 
-  // Passing pointer through invariant.group.barrier to avoid propagation of
+  // Passing pointer through launder.invariant.group to avoid propagation of
   // vptrs information which may be included in previous type.
   // To not break LTO with different optimizations levels, we do it regardless
   // of optimization level.
   if (CGM.getCodeGenOpts().StrictVTablePointers &&
       allocator->isReservedGlobalPlacementOperator())
-    result = Address(Builder.CreateInvariantGroupBarrier(result.getPointer()),
+    result = Address(Builder.CreateLaunderInvariantGroup(result.getPointer()),
                      result.getAlignment());
 
   EmitNewInitializer(*this, E, allocType, elementTy, result, numElements,