diff --git a/llvm/include/llvm/Analysis/ObjCARCAnalysisUtils.h b/llvm/include/llvm/Analysis/ObjCARCAnalysisUtils.h
--- a/llvm/include/llvm/Analysis/ObjCARCAnalysisUtils.h
+++ b/llvm/include/llvm/Analysis/ObjCARCAnalysisUtils.h
@@ -28,7 +28,6 @@
 #include "llvm/Analysis/ObjCARCInstKind.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Analysis/ValueTracking.h"
-#include "llvm/IR/CallSite.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/LLVMContext.h"
@@ -191,13 +190,12 @@
 
 /// Helper for GetARCInstKind. Determines what kind of construct CS
 /// is.
-inline ARCInstKind GetCallSiteClass(ImmutableCallSite CS) {
-  for (ImmutableCallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
-       I != E; ++I)
+inline ARCInstKind GetCallSiteClass(const CallBase &CB) {
+  for (auto I = CB.arg_begin(), E = CB.arg_end(); I != E; ++I)
     if (IsPotentialRetainableObjPtr(*I))
-      return CS.onlyReadsMemory() ? ARCInstKind::User : ARCInstKind::CallOrUser;
+      return CB.onlyReadsMemory() ? ARCInstKind::User : ARCInstKind::CallOrUser;
 
-  return CS.onlyReadsMemory() ? ARCInstKind::None : ARCInstKind::Call;
+  return CB.onlyReadsMemory() ? ARCInstKind::None : ARCInstKind::Call;
 }
 
 /// Return true if this value refers to a distinct and identifiable
diff --git a/llvm/lib/Analysis/ObjCARCInstKind.cpp b/llvm/lib/Analysis/ObjCARCInstKind.cpp
--- a/llvm/lib/Analysis/ObjCARCInstKind.cpp
+++ b/llvm/lib/Analysis/ObjCARCInstKind.cpp
@@ -234,11 +234,11 @@
       }
 
       // Otherwise, be conservative.
-      return GetCallSiteClass(CI);
+      return GetCallSiteClass(*CI);
     }
     case Instruction::Invoke:
       // Otherwise, be conservative.
-      return GetCallSiteClass(cast<InvokeInst>(I));
+      return GetCallSiteClass(cast<InvokeInst>(*I));
     case Instruction::BitCast:
     case Instruction::GetElementPtr:
     case Instruction::Select:
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCAPElim.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCAPElim.cpp
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCAPElim.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCAPElim.cpp
@@ -41,7 +41,7 @@
     void getAnalysisUsage(AnalysisUsage &AU) const override;
     bool runOnModule(Module &M) override;
 
-    static bool MayAutorelease(ImmutableCallSite CS, unsigned Depth = 0);
+    static bool MayAutorelease(const CallBase &CB, unsigned Depth = 0);
     static bool OptimizeBB(BasicBlock *BB);
 
   public:
@@ -68,18 +68,17 @@
 
 /// Interprocedurally determine if calls made by the given call site can
 /// possibly produce autoreleases.
-bool ObjCARCAPElim::MayAutorelease(ImmutableCallSite CS, unsigned Depth) {
-  if (const Function *Callee = CS.getCalledFunction()) {
+bool ObjCARCAPElim::MayAutorelease(const CallBase &CB, unsigned Depth) {
+  if (const Function *Callee = CB.getCalledFunction()) {
     if (!Callee->hasExactDefinition())
       return true;
     for (const BasicBlock &BB : *Callee) {
       for (const Instruction &I : BB)
-        if (ImmutableCallSite JCS = ImmutableCallSite(&I))
+        if (const CallBase *JCB = dyn_cast<CallBase>(&I))
           // This recursion depth limit is arbitrary. It's just great
           // enough to cover known interesting testcases.
-          if (Depth < 3 &&
-              !JCS.onlyReadsMemory() &&
-              MayAutorelease(JCS, Depth + 1))
+          if (Depth < 3 && !JCB->onlyReadsMemory() &&
+              MayAutorelease(*JCB, Depth + 1))
             return true;
     }
     return false;
@@ -115,7 +114,7 @@
       Push = nullptr;
       break;
     case ARCInstKind::CallOrUser:
-      if (MayAutorelease(ImmutableCallSite(Inst)))
+      if (MayAutorelease(cast<CallBase>(*Inst)))
         Push = nullptr;
       break;
     default:
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -43,7 +43,6 @@
 #include "llvm/Analysis/ObjCARCInstKind.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
-#include "llvm/IR/CallSite.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
@@ -610,8 +609,7 @@
 ObjCARCOpt::OptimizeRetainRVCall(Function &F, Instruction *RetainRV) {
   // Check for the argument being from an immediately preceding call or invoke.
   const Value *Arg = GetArgRCIdentityRoot(RetainRV);
-  ImmutableCallSite CS(Arg);
-  if (const Instruction *Call = CS.getInstruction()) {
+  if (const Instruction *Call = dyn_cast<CallBase>(Arg)) {
     if (Call->getParent() == RetainRV->getParent()) {
       BasicBlock::const_iterator I(Call);
       ++I;
diff --git a/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp b/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
--- a/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
@@ -25,7 +25,6 @@
 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/CFG.h"
-#include "llvm/IR/CallSite.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Module.h"
@@ -286,8 +285,7 @@
     // what they are doing and don't add any more.
     for (auto &I : *BB) {
       if (isa<CallInst>(&I) || isa<InvokeInst>(&I)) {
-        ImmutableCallSite CS(&I);
-        if (const Function *F = CS.getCalledFunction()) {
+        if (const Function *F = cast<CallBase>(I).getCalledFunction()) {
           if (F->getIntrinsicID() == Intrinsic::prefetch)
             return MadeChange;
           if (TTI->isLoweredToCall(F))
diff --git a/llvm/lib/Transforms/Scalar/SpeculateAroundPHIs.cpp b/llvm/lib/Transforms/Scalar/SpeculateAroundPHIs.cpp
--- a/llvm/lib/Transforms/Scalar/SpeculateAroundPHIs.cpp
+++ b/llvm/lib/Transforms/Scalar/SpeculateAroundPHIs.cpp
@@ -14,7 +14,6 @@
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/CallSite.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
@@ -68,8 +67,8 @@
       return false;
     }
 
-    if (auto CS = ImmutableCallSite(UI)) {
-      if (CS.isConvergent() || CS.cannotDuplicate()) {
+    if (const auto *CS = dyn_cast<CallBase>(UI)) {
+      if (CS->isConvergent() || CS->cannotDuplicate()) {
         LLVM_DEBUG(dbgs() << "  Unsafe: convergent "
                    "callsite cannot de duplicated: " << *UI << '\n');
         return false;