[CallSite removal][MemCpyOptimizer] Replace CallSite with CallBase. NFC

[craig.topper]

Summary

There are also some adjustments to use MaybeAlign in here due
to CallBase::getParamAlignment() being deprecated. It would
be a little cleaner if getOrEnforceKnownAlignment was migrated
to Align/MaybeAlign.

[mtrofin]

lgtm, one nit

llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp

1353

can we capitalize i and e here?

llvm/include/llvm/Transforms/IPO/Attributor.h

struct IRPosition {
   }
 
   /// Create a position describing the argument of \p CB at position \p ArgNo.
   static const IRPosition callsite_argument(const CallBase &CB,
                                             unsigned ArgNo) {
     return IRPosition(const_cast<CallBase &>(CB), Kind(ArgNo));
   }
 
-  /// Create a position describing the function scope of \p ICS.
-  static const IRPosition callsite_function(ImmutableCallSite ICS) {
-    return IRPosition::callsite_function(cast<CallBase>(*ICS.getInstruction()));
-  }
-
-  /// Create a position describing the returned value of \p ICS.
-  static const IRPosition callsite_returned(ImmutableCallSite ICS) {
-    return IRPosition::callsite_returned(cast<CallBase>(*ICS.getInstruction()));
-  }
-
-  /// Create a position describing the argument of \p ICS at position \p ArgNo.
-  static const IRPosition callsite_argument(ImmutableCallSite ICS,
-                                            unsigned ArgNo) {
-    return IRPosition::callsite_argument(cast<CallBase>(*ICS.getInstruction()),
-                                         ArgNo);
-  }
-
   /// Create a position describing the argument of \p ACS at position \p ArgNo.
   static const IRPosition callsite_argument(AbstractCallSite ACS,
                                             unsigned ArgNo) {
     if (ACS.getNumArgOperands() <= ArgNo)
       return IRPosition();
     int CSArgNo = ACS.getCallArgOperandNo(ArgNo);
     if (CSArgNo >= 0)
       return IRPosition::callsite_argument(
void getAttrs(ArrayRef<Attribute::AttrKind> AKs,
                 Attributor *A = nullptr) const;
 
   /// Remove the attribute of kind \p AKs existing in the IR at this position.
   void removeAttrs(ArrayRef<Attribute::AttrKind> AKs) const {
     if (getPositionKind() == IRP_INVALID || getPositionKind() == IRP_FLOAT)
       return;
 
     AttributeList AttrList;
-    CallSite CS = CallSite(&getAnchorValue());
-    if (CS)
-      AttrList = CS.getAttributes();
+    auto *CB = dyn_cast<CallBase>(&getAnchorValue());
+    if (CB)
+      AttrList = CB->getAttributes();
     else
       AttrList = getAssociatedFunction()->getAttributes();
 
     LLVMContext &Ctx = getAnchorValue().getContext();
     for (Attribute::AttrKind AK : AKs)
       AttrList = AttrList.removeAttribute(Ctx, getAttrIdx(), AK);
 
-    if (CS)
-      CS.setAttributes(AttrList);
+    if (CB)
+      CB->setAttributes(AttrList);
     else
       getAssociatedFunction()->setAttributes(AttrList);
   }
 
   bool isAnyCallSitePosition() const {
     switch (getPositionKind()) {
     case IRPosition::IRP_CALL_SITE:
     case IRPosition::IRP_CALL_SITE_RETURNED:

llvm/include/llvm/Transforms/Scalar/MemCpyOptimizer.h

 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H
 #define LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H
 
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/CallSite.h"
 #include "llvm/IR/PassManager.h"
 #include <cstdint>
 #include <functional>
 
 namespace llvm {
 
 class AssumptionCache;
 class CallInst;
private:
   bool processMemSet(MemSetInst *SI, BasicBlock::iterator &BBI);
   bool processMemCpy(MemCpyInst *M);
   bool processMemMove(MemMoveInst *M);
   bool performCallSlotOptzn(Instruction *cpy, Value *cpyDst, Value *cpySrc,
                             uint64_t cpyLen, unsigned cpyAlign, CallInst *C);
   bool processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep);
   bool processMemSetMemCpyDependence(MemCpyInst *M, MemSetInst *MDep);
   bool performMemCpyToMemSetOptzn(MemCpyInst *M, MemSetInst *MDep);
-  bool processByValArgument(CallSite CS, unsigned ArgNo);
+  bool processByValArgument(CallBase &CB, unsigned ArgNo);
   Instruction *tryMergingIntoMemset(Instruction *I, Value *StartPtr,
                                     Value *ByteVal);
 
   bool iterateOnFunction(Function &F);
 };
 
 } // end namespace llvm
 
 #endif // LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H

llvm/lib/Transforms/IPO/Attributor.cpp

IRAttributeManifest::manifestAttrs(Attributor &A, const IRPosition &IRP,
   case IRPosition::IRP_ARGUMENT:
   case IRPosition::IRP_FUNCTION:
   case IRPosition::IRP_RETURNED:
     Attrs = ScopeFn->getAttributes();
     break;
   case IRPosition::IRP_CALL_SITE:
   case IRPosition::IRP_CALL_SITE_RETURNED:
   case IRPosition::IRP_CALL_SITE_ARGUMENT:
-    Attrs = ImmutableCallSite(&IRP.getAnchorValue()).getAttributes();
+    Attrs = cast<CallBase>(IRP.getAnchorValue()).getAttributes();
     break;
   }
 
   ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
   LLVMContext &Ctx = IRP.getAnchorValue().getContext();
   for (const Attribute &Attr : DeducedAttrs) {
     if (!addIfNotExistent(Ctx, Attr, Attrs, IRP.getAttrIdx()))
       continue;
 
     HasChanged = ChangeStatus::CHANGED;
   }
 
   if (HasChanged == ChangeStatus::UNCHANGED)
     return HasChanged;
 
   switch (PK) {
   case IRPosition::IRP_ARGUMENT:
   case IRPosition::IRP_FUNCTION:
   case IRPosition::IRP_RETURNED:
     ScopeFn->setAttributes(Attrs);
     break;
   case IRPosition::IRP_CALL_SITE:
   case IRPosition::IRP_CALL_SITE_RETURNED:
   case IRPosition::IRP_CALL_SITE_ARGUMENT:
-    CallSite(&IRP.getAnchorValue()).setAttributes(Attrs);
+    cast<CallBase>(IRP.getAnchorValue()).setAttributes(Attrs);
     break;
   case IRPosition::IRP_INVALID:
   case IRPosition::IRP_FLOAT:
     break;
   }
 
   return HasChanged;
 }
 
 const IRPosition IRPosition::EmptyKey(255);
 const IRPosition IRPosition::TombstoneKey(256);
 
 SubsumingPositionIterator::SubsumingPositionIterator(const IRPosition &IRP) {
   IRPositions.emplace_back(IRP);
 
-  ImmutableCallSite ICS(&IRP.getAnchorValue());
+  const auto *CB = dyn_cast<CallBase>(&IRP.getAnchorValue());
   switch (IRP.getPositionKind()) {
   case IRPosition::IRP_INVALID:
   case IRPosition::IRP_FLOAT:
   case IRPosition::IRP_FUNCTION:
     return;
   case IRPosition::IRP_ARGUMENT:
   case IRPosition::IRP_RETURNED:
     IRPositions.emplace_back(IRPosition::function(*IRP.getAnchorScope()));
     return;
   case IRPosition::IRP_CALL_SITE:
-    assert(ICS && "Expected call site!");
+    assert(CB && "Expected call site!");
     // TODO: We need to look at the operand bundles similar to the redirection
     //       in CallBase.
-    if (!ICS.hasOperandBundles())
-      if (const Function *Callee = ICS.getCalledFunction())
+    if (!CB->hasOperandBundles())
+      if (const Function *Callee = CB->getCalledFunction())
         IRPositions.emplace_back(IRPosition::function(*Callee));
     return;
   case IRPosition::IRP_CALL_SITE_RETURNED:
-    assert(ICS && "Expected call site!");
+    assert(CB && "Expected call site!");
     // TODO: We need to look at the operand bundles similar to the redirection
     //       in CallBase.
-    if (!ICS.hasOperandBundles()) {
-      if (const Function *Callee = ICS.getCalledFunction()) {
+    if (!CB->hasOperandBundles()) {
+      if (const Function *Callee = CB->getCalledFunction()) {
         IRPositions.emplace_back(IRPosition::returned(*Callee));
         IRPositions.emplace_back(IRPosition::function(*Callee));
         for (const Argument &Arg : Callee->args())
           if (Arg.hasReturnedAttr()) {
             IRPositions.emplace_back(
-                IRPosition::callsite_argument(ICS, Arg.getArgNo()));
+                IRPosition::callsite_argument(*CB, Arg.getArgNo()));
             IRPositions.emplace_back(
-                IRPosition::value(*ICS.getArgOperand(Arg.getArgNo())));
+                IRPosition::value(*CB->getArgOperand(Arg.getArgNo())));
             IRPositions.emplace_back(IRPosition::argument(Arg));
           }
       }
     }
-    IRPositions.emplace_back(
-        IRPosition::callsite_function(cast<CallBase>(*ICS.getInstruction())));
+    IRPositions.emplace_back(IRPosition::callsite_function(*CB));
     return;
   case IRPosition::IRP_CALL_SITE_ARGUMENT: {
     int ArgNo = IRP.getArgNo();
-    assert(ICS && ArgNo >= 0 && "Expected call site!");
+    assert(CB && ArgNo >= 0 && "Expected call site!");
     // TODO: We need to look at the operand bundles similar to the redirection
     //       in CallBase.
-    if (!ICS.hasOperandBundles()) {
-      const Function *Callee = ICS.getCalledFunction();
+    if (!CB->hasOperandBundles()) {
+      const Function *Callee = CB->getCalledFunction();
       if (Callee && Callee->arg_size() > unsigned(ArgNo))
         IRPositions.emplace_back(IRPosition::argument(*Callee->getArg(ArgNo)));
       if (Callee)
         IRPositions.emplace_back(IRPosition::function(*Callee));
     }
     IRPositions.emplace_back(IRPosition::value(IRP.getAssociatedValue()));
     return;
   }

 }
 
 bool IRPosition::getAttrsFromIRAttr(Attribute::AttrKind AK,
                                     SmallVectorImpl<Attribute> &Attrs) const {
   if (getPositionKind() == IRP_INVALID || getPositionKind() == IRP_FLOAT)
     return false;
 
   AttributeList AttrList;
-  if (ImmutableCallSite ICS = ImmutableCallSite(&getAnchorValue()))
-    AttrList = ICS.getAttributes();
+  if (const auto *CB = dyn_cast<CallBase>(&getAnchorValue()))
+    AttrList = CB->getAttributes();
   else
     AttrList = getAssociatedFunction()->getAttributes();
 
   bool HasAttr = AttrList.hasAttribute(getAttrIdx(), AK);
   if (HasAttr)
     Attrs.push_back(AttrList.getAttribute(getAttrIdx(), AK));
   return HasAttr;
 }
bool Attributor::isAssumedDead(const Use &U,
                                const AbstractAttribute *QueryingAA,
                                const AAIsDead *FnLivenessAA,
                                bool CheckBBLivenessOnly, DepClassTy DepClass) {
   Instruction *UserI = dyn_cast<Instruction>(U.getUser());
   if (!UserI)
     return isAssumedDead(IRPosition::value(*U.get()), QueryingAA, FnLivenessAA,
                          CheckBBLivenessOnly, DepClass);
 
-  if (CallSite CS = CallSite(UserI)) {
+  if (auto *CB = dyn_cast<CallBase>(UserI)) {
     // For call site argument uses we can check if the argument is
     // unused/dead.
-    if (CS.isArgOperand(&U)) {
+    if (CB->isArgOperand(&U)) {
       const IRPosition &CSArgPos =
-          IRPosition::callsite_argument(CS, CS.getArgumentNo(&U));
+          IRPosition::callsite_argument(*CB, CB->getArgOperandNo(&U));
       return isAssumedDead(CSArgPos, QueryingAA, FnLivenessAA,
                            CheckBBLivenessOnly, DepClass);
     }
   } else if (ReturnInst *RI = dyn_cast<ReturnInst>(UserI)) {
     const IRPosition &RetPos = IRPosition::returned(*RI->getFunction());
     return isAssumedDead(RetPos, QueryingAA, FnLivenessAA, CheckBBLivenessOnly,
                          DepClass);
   } else if (PHINode *PHI = dyn_cast<PHINode>(UserI)) {
for (Instruction &I : instructions(&F)) {
 
     // To allow easy access to all instructions in a function with a given
     // opcode we store them in the InfoCache. As not all opcodes are interesting
     // to concrete attributes we only cache the ones that are as identified in
     // the following switch.
     // Note: There are no concrete attributes now so this is initially empty.
     switch (I.getOpcode()) {
     default:
-      assert((!ImmutableCallSite(&I)) && (!isa<CallBase>(&I)) &&
-             "New call site/base instruction type needs to be known in the "
+      assert(!isa<CallBase>(&I) &&
+             "New call base instruction type needs to be known in the "
              "Attributor.");
       break;
     case Instruction::Call:
       // Calls are interesting on their own, additionally:
       // For `llvm.assume` calls we also fill the KnowledgeMap as we find them.
       // For `must-tail` calls we remember the caller and callee.
       if (IntrinsicInst *Assume = dyn_cast<IntrinsicInst>(&I)) {
         if (Assume->getIntrinsicID() == Intrinsic::assume)
if (F.isDeclaration())
     return;
 
   // In non-module runs we need to look at the call sites of a function to
   // determine if it is part of a must-tail call edge. This will influence what
   // attributes we can derive.
   InformationCache::FunctionInfo &FI = InfoCache.getFunctionInfo(F);
   if (!isModulePass() && !FI.CalledViaMustTail) {
     for (const Use &U : F.uses())
-      if (ImmutableCallSite ICS = ImmutableCallSite(U.getUser()))
-        if (ICS.isCallee(&U) && ICS.isMustTailCall())
+      if (const auto *CB = dyn_cast<CallBase>(U.getUser()))
+        if (CB->isCallee(&U) && CB->isMustTailCall())
           FI.CalledViaMustTail = true;
   }
 
   IRPosition FPos = IRPosition::function(F);
 
   // Check for dead BasicBlocks in every function.
   // We need dead instruction detection because we do not want to deal with
   // broken IR in which SSA rules do not apply.
if (Arg.getType()->isPointerTy()) {
       getOrCreateAAFor<AANoFree>(ArgPos);
 
       // Every argument with pointer type might be privatizable (or promotable)
       getOrCreateAAFor<AAPrivatizablePtr>(ArgPos);
     }
   }
 
   auto CallSitePred = [&](Instruction &I) -> bool {
-    CallSite CS(&I);
-    IRPosition CSRetPos = IRPosition::callsite_returned(CS);
+    auto *CB = dyn_cast<CallBase>(&I);
+    IRPosition CBRetPos = IRPosition::callsite_returned(*CB);
 
     // Call sites might be dead if they do not have side effects and no live
     // users. The return value might be dead if there are no live users.
-    getOrCreateAAFor<AAIsDead>(CSRetPos);
+    getOrCreateAAFor<AAIsDead>(CBRetPos);
 
-    Function *Callee = CS.getCalledFunction();
+    Function *Callee = CB->getCalledFunction();
     // TODO: Even if the callee is not known now we might be able to simplify
     //       the call/callee.
     if (!Callee)
       return true;
 
     // Skip declarations except if annotations on their call sites were
     // explicitly requested.
     if (!AnnotateDeclarationCallSites && Callee->isDeclaration() &&
         !Callee->hasMetadata(LLVMContext::MD_callback))
       return true;
 
-    if (!Callee->getReturnType()->isVoidTy() && !CS->use_empty()) {
+    if (!Callee->getReturnType()->isVoidTy() && !CB->use_empty()) {
 
-      IRPosition CSRetPos = IRPosition::callsite_returned(CS);
+      IRPosition CBRetPos = IRPosition::callsite_returned(*CB);
 
       // Call site return integer values might be limited by a constant range.
       if (Callee->getReturnType()->isIntegerTy())
-        getOrCreateAAFor<AAValueConstantRange>(CSRetPos);
+        getOrCreateAAFor<AAValueConstantRange>(CBRetPos);
     }
 
-    for (int i = 0, e = CS.getNumArgOperands(); i < e; i++) {
+    for (int i = 0, e = CB->getNumArgOperands(); i < e; i++) {
 
-      IRPosition CSArgPos = IRPosition::callsite_argument(CS, i);
+      IRPosition CBArgPos = IRPosition::callsite_argument(*CB, i);
 
       // Every call site argument might be dead.
-      getOrCreateAAFor<AAIsDead>(CSArgPos);
+      getOrCreateAAFor<AAIsDead>(CBArgPos);
 
       // Call site argument might be simplified.
-      getOrCreateAAFor<AAValueSimplify>(CSArgPos);
+      getOrCreateAAFor<AAValueSimplify>(CBArgPos);
 
-      if (!CS.getArgument(i)->getType()->isPointerTy())
+      if (!CB->getArgOperand(i)->getType()->isPointerTy())
         continue;
 
       // Call site argument attribute "non-null".
-      getOrCreateAAFor<AANonNull>(CSArgPos);
+      getOrCreateAAFor<AANonNull>(CBArgPos);
 
       // Call site argument attribute "no-alias".
-      getOrCreateAAFor<AANoAlias>(CSArgPos);
+      getOrCreateAAFor<AANoAlias>(CBArgPos);
 
       // Call site argument attribute "dereferenceable".
-      getOrCreateAAFor<AADereferenceable>(CSArgPos);
+      getOrCreateAAFor<AADereferenceable>(CBArgPos);
 
       // Call site argument attribute "align".
-      getOrCreateAAFor<AAAlign>(CSArgPos);
+      getOrCreateAAFor<AAAlign>(CBArgPos);
 
       // Call site argument attribute
       // "readnone/readonly/writeonly/..."
-      getOrCreateAAFor<AAMemoryBehavior>(CSArgPos);
+      getOrCreateAAFor<AAMemoryBehavior>(CBArgPos);
 
       // Call site argument attribute "nofree".
-      getOrCreateAAFor<AANoFree>(CSArgPos);
+      getOrCreateAAFor<AANoFree>(CBArgPos);
     }
     return true;
   };
 
   auto &OpcodeInstMap = InfoCache.getOpcodeInstMapForFunction(F);
   bool Success;
   Success = checkForAllInstructionsImpl(
       nullptr, OpcodeInstMap, CallSitePred, nullptr, nullptr,
for (Function *F : Functions) {
     else
       NumFnWithoutExactDefinition++;
 
     // We look at internal functions only on-demand but if any use is not a
     // direct call or outside the current set of analyzed functions, we have to
     // do it eagerly.
     if (F->hasLocalLinkage()) {
       if (llvm::all_of(F->uses(), [&Functions](const Use &U) {
-            ImmutableCallSite ICS(U.getUser());
-            return ICS && ICS.isCallee(&U) &&
-                   Functions.count(const_cast<Function *>(ICS.getCaller()));
+            const auto *CB = dyn_cast<CallBase>(U.getUser());
+            return CB && CB->isCallee(&U) &&
+                   Functions.count(const_cast<Function *>(CB->getCaller()));
           }))
         continue;
     }
 
     // Populate the Attributor with abstract attribute opportunities in the
     // function and the information cache with IR information.
     A.identifyDefaultAbstractAttributes(*F);
   }

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

if (Iteration++ >= MaxValues)
       return false;
 
     // Explicitly look through calls with a "returned" attribute if we do
     // not have a pointer as stripPointerCasts only works on them.
     Value *NewV = nullptr;
     if (V->getType()->isPointerTy()) {
       NewV = V->stripPointerCasts();
     } else {
-      CallSite CS(V);
-      if (CS && CS.getCalledFunction()) {
-        for (Argument &Arg : CS.getCalledFunction()->args())
+      auto *CB = dyn_cast<CallBase>(V);
+      if (CB && CB->getCalledFunction()) {
+        for (Argument &Arg : CB->getCalledFunction()->args())
           if (Arg.hasReturnedAttr()) {
-            NewV = CS.getArgOperand(Arg.getArgNo());
+            NewV = CB->getArgOperand(Arg.getArgNo());
             break;
           }
       }
     }
     if (NewV && NewV != V) {
       Worklist.push_back({NewV, CtxI});
       continue;
     }
auto Opcodes = {
         (unsigned)Instruction::Invoke,      (unsigned)Instruction::CallBr,
         (unsigned)Instruction::Call,        (unsigned)Instruction::CleanupRet,
         (unsigned)Instruction::CatchSwitch, (unsigned)Instruction::Resume};
 
     auto CheckForNoUnwind = [&](Instruction &I) {
       if (!I.mayThrow())
         return true;
 
-      if (ImmutableCallSite ICS = ImmutableCallSite(&I)) {
+      if (const auto *CB = dyn_cast<CallBase>(&I)) {
         const auto &NoUnwindAA =
-            A.getAAFor<AANoUnwind>(*this, IRPosition::callsite_function(ICS));
+            A.getAAFor<AANoUnwind>(*this, IRPosition::callsite_function(*CB));
         return NoUnwindAA.isAssumedNoUnwind();
       }
       return false;
     };
 
     if (!A.checkForAllInstructions(CheckForNoUnwind, *this, Opcodes))
       return indicatePessimisticFixpoint();
 
if (auto *II = dyn_cast<IntrinsicInst>(I)) {
     default:
       return false;
     }
   }
   return false;
 }
 
 bool AANoSyncImpl::isVolatile(Instruction *I) {
-  assert(!ImmutableCallSite(I) && !isa<CallBase>(I) &&
-         "Calls should not be checked here");
+  assert(!isa<CallBase>(I) && "Calls should not be checked here");
 
   switch (I->getOpcode()) {
   case Instruction::AtomicRMW:
     return cast<AtomicRMWInst>(I)->isVolatile();
   case Instruction::Store:
     return cast<StoreInst>(I)->isVolatile();
   case Instruction::Load:
     return cast<LoadInst>(I)->isVolatile();
   case Instruction::AtomicCmpXchg:
     return cast<AtomicCmpXchgInst>(I)->isVolatile();
   default:
     return false;
   }
 }
 
 ChangeStatus AANoSyncImpl::updateImpl(Attributor &A) {
 
   auto CheckRWInstForNoSync = [&](Instruction &I) {
     /// We are looking for volatile instructions or Non-Relaxed atomics.
     /// FIXME: We should improve the handling of intrinsics.
 
     if (isa<IntrinsicInst>(&I) && isNoSyncIntrinsic(&I))
       return true;
 
-    if (ImmutableCallSite ICS = ImmutableCallSite(&I)) {
-      if (ICS.hasFnAttr(Attribute::NoSync))
+    if (const auto *CB = dyn_cast<CallBase>(&I)) {
+      if (CB->hasFnAttr(Attribute::NoSync))
         return true;
 
       const auto &NoSyncAA =
-          A.getAAFor<AANoSync>(*this, IRPosition::callsite_function(ICS));
+          A.getAAFor<AANoSync>(*this, IRPosition::callsite_function(*CB));
       if (NoSyncAA.isAssumedNoSync())
         return true;
       return false;
     }
 
     if (!isVolatile(&I) && !isNonRelaxedAtomic(&I))
       return true;
 
     return false;
   };
 
   auto CheckForNoSync = [&](Instruction &I) {
     // At this point we handled all read/write effects and they are all
     // nosync, so they can be skipped.
     if (I.mayReadOrWriteMemory())
       return true;
 
     // non-convergent and readnone imply nosync.
-    return !ImmutableCallSite(&I).isConvergent();
+    return !cast<CallBase>(I).isConvergent();
   };
 
   if (!A.checkForAllReadWriteInstructions(CheckRWInstForNoSync, *this) ||
       !A.checkForAllCallLikeInstructions(CheckForNoSync, *this))
     return indicatePessimisticFixpoint();
 
   return ChangeStatus::UNCHANGED;
 }

 /// ------------------------ No-Free Attributes ----------------------------
 
 struct AANoFreeImpl : public AANoFree {
   AANoFreeImpl(const IRPosition &IRP) : AANoFree(IRP) {}
 
   /// See AbstractAttribute::updateImpl(...).
   ChangeStatus updateImpl(Attributor &A) override {
     auto CheckForNoFree = [&](Instruction &I) {
-      ImmutableCallSite ICS(&I);
-      if (ICS.hasFnAttr(Attribute::NoFree))
+      const auto &CB = cast<CallBase>(I);
+      if (CB.hasFnAttr(Attribute::NoFree))
         return true;
 
       const auto &NoFreeAA =
-          A.getAAFor<AANoFree>(*this, IRPosition::callsite_function(ICS));
+          A.getAAFor<AANoFree>(*this, IRPosition::callsite_function(CB));
       return NoFreeAA.isAssumedNoFree();
     };
 
     if (!A.checkForAllCallLikeInstructions(CheckForNoFree, *this))
       return indicatePessimisticFixpoint();
     return ChangeStatus::UNCHANGED;
   }
 
static int64_t getKnownNonNullAndDerefBytesForUse(
   if (!UseV->getType()->isPointerTy())
     return 0;
 
   Type *PtrTy = UseV->getType();
   const Function *F = I->getFunction();
   bool NullPointerIsDefined =
       F ? llvm::NullPointerIsDefined(F, PtrTy->getPointerAddressSpace()) : true;
   const DataLayout &DL = A.getInfoCache().getDL();
-  if (ImmutableCallSite ICS = ImmutableCallSite(I)) {
-    if (ICS.isBundleOperand(U))
+  if (const auto *CB = dyn_cast<CallBase>(I)) {
+    if (CB->isBundleOperand(U))
       return 0;
 
-    if (ICS.isCallee(U)) {
+    if (CB->isCallee(U)) {
       IsNonNull |= !NullPointerIsDefined;
       return 0;
     }
 
-    unsigned ArgNo = ICS.getArgumentNo(U);
-    IRPosition IRP = IRPosition::callsite_argument(ICS, ArgNo);
+    unsigned ArgNo = CB->getArgOperandNo(U);
+    IRPosition IRP = IRPosition::callsite_argument(*CB, ArgNo);
     // As long as we only use known information there is no need to track
     // dependences here.
     auto &DerefAA = A.getAAFor<AADereferenceable>(QueryingAA, IRP,
                                                   /* TrackDependence */ false);
     IsNonNull |= DerefAA.isKnownNonNull();
     return DerefAA.getKnownDereferenceableBytes();
   }
 
if (A.checkForAllCallSites(CallSitePred, *this, true, AllCallSitesKnown)) {
       // live, another update is triggered.
       if (AllCallSitesKnown)
         indicateOptimisticFixpoint();
       return ChangeStatus::UNCHANGED;
     }
 
     // If the above check does not hold anymore we look at the calls.
     auto CheckForNoRecurse = [&](Instruction &I) {
-      ImmutableCallSite ICS(&I);
-      if (ICS.hasFnAttr(Attribute::NoRecurse))
+      const auto &CB = cast<CallBase>(I);
+      if (CB.hasFnAttr(Attribute::NoRecurse))
         return true;
 
       const auto &NoRecurseAA =
-          A.getAAFor<AANoRecurse>(*this, IRPosition::callsite_function(ICS));
+          A.getAAFor<AANoRecurse>(*this, IRPosition::callsite_function(CB));
       if (!NoRecurseAA.isAssumedNoRecurse())
         return false;
 
       // Recursion to the same function
-      if (ICS.getCalledFunction() == getAnchorScope())
+      if (CB.getCalledFunction() == getAnchorScope())
         return false;
 
       return true;
     };
 
     if (!A.checkForAllCallLikeInstructions(CheckForNoRecurse, *this))
       return indicatePessimisticFixpoint();
     return ChangeStatus::UNCHANGED;
void initialize(Attributor &A) override {
     Function *F = getAnchorScope();
     if (!F || !A.isFunctionIPOAmendable(*F) || mayContainUnboundedCycle(*F, A))
       indicatePessimisticFixpoint();
   }
 
   /// See AbstractAttribute::updateImpl(...).
   ChangeStatus updateImpl(Attributor &A) override {
     auto CheckForWillReturn = [&](Instruction &I) {
-      IRPosition IPos = IRPosition::callsite_function(ImmutableCallSite(&I));
+      IRPosition IPos = IRPosition::callsite_function(cast<CallBase>(I));
       const auto &WillReturnAA = A.getAAFor<AAWillReturn>(*this, IPos);
       if (WillReturnAA.isKnownWillReturn())
         return true;
       if (!WillReturnAA.isAssumedWillReturn())
         return false;
       const auto &NoRecurseAA = A.getAAFor<AANoRecurse>(*this, IPos);
       return NoRecurseAA.isAssumedNoRecurse();
     };

 };
 
 struct AANoAliasCallSiteArgument final : AANoAliasImpl {
   AANoAliasCallSiteArgument(const IRPosition &IRP) : AANoAliasImpl(IRP) {}
 
   /// See AbstractAttribute::initialize(...).
   void initialize(Attributor &A) override {
     // See callsite argument attribute and callee argument attribute.
-    ImmutableCallSite ICS(&getAnchorValue());
-    if (ICS.paramHasAttr(getArgNo(), Attribute::NoAlias))
+    const auto &CB = cast<CallBase>(getAnchorValue());
+    if (CB.paramHasAttr(getArgNo(), Attribute::NoAlias))
       indicateOptimisticFixpoint();
     Value &Val = getAssociatedValue();
     if (isa<ConstantPointerNull>(Val) &&
         !NullPointerIsDefined(getAnchorScope(),
                               Val.getType()->getPointerAddressSpace()))
       indicateOptimisticFixpoint();
   }
 
   /// Determine if the underlying value may alias with the call site argument
   /// \p OtherArgNo of \p ICS (= the underlying call site).
   bool mayAliasWithArgument(Attributor &A, AAResults *&AAR,
                             const AAMemoryBehavior &MemBehaviorAA,
-                            ImmutableCallSite ICS, unsigned OtherArgNo) {
+                            const CallBase &CB, unsigned OtherArgNo) {
     // We do not need to worry about aliasing with the underlying IRP.
     if (this->getArgNo() == (int)OtherArgNo)
       return false;
 
     // If it is not a pointer or pointer vector we do not alias.
-    const Value *ArgOp = ICS.getArgOperand(OtherArgNo);
+    const Value *ArgOp = CB.getArgOperand(OtherArgNo);
     if (!ArgOp->getType()->isPtrOrPtrVectorTy())
       return false;
 
-    auto &ICSArgMemBehaviorAA = A.getAAFor<AAMemoryBehavior>(
-        *this, IRPosition::callsite_argument(ICS, OtherArgNo),
+    auto &CBArgMemBehaviorAA = A.getAAFor<AAMemoryBehavior>(
+        *this, IRPosition::callsite_argument(CB, OtherArgNo),
         /* TrackDependence */ false);
 
     // If the argument is readnone, there is no read-write aliasing.
-    if (ICSArgMemBehaviorAA.isAssumedReadNone()) {
-      A.recordDependence(ICSArgMemBehaviorAA, *this, DepClassTy::OPTIONAL);
+    if (CBArgMemBehaviorAA.isAssumedReadNone()) {
+      A.recordDependence(CBArgMemBehaviorAA, *this, DepClassTy::OPTIONAL);
       return false;
     }
 
     // If the argument is readonly and the underlying value is readonly, there
     // is no read-write aliasing.
     bool IsReadOnly = MemBehaviorAA.isAssumedReadOnly();
-    if (ICSArgMemBehaviorAA.isAssumedReadOnly() && IsReadOnly) {
+    if (CBArgMemBehaviorAA.isAssumedReadOnly() && IsReadOnly) {
       A.recordDependence(MemBehaviorAA, *this, DepClassTy::OPTIONAL);
-      A.recordDependence(ICSArgMemBehaviorAA, *this, DepClassTy::OPTIONAL);
+      A.recordDependence(CBArgMemBehaviorAA, *this, DepClassTy::OPTIONAL);
       return false;
     }
 
     // We have to utilize actual alias analysis queries so we need the object.
     if (!AAR)
       AAR = A.getInfoCache().getAAResultsForFunction(*getAnchorScope());
 
     // Try to rule it out at the call site.
if (!NoCaptureAA.isAssumedNoCaptureMaybeReturned()) {
         return false;
       }
     }
     A.recordDependence(NoCaptureAA, *this, DepClassTy::OPTIONAL);
 
     // Check there is no other pointer argument which could alias with the
     // value passed at this call site.
     // TODO: AbstractCallSite
-    ImmutableCallSite ICS(&getAnchorValue());
-    for (unsigned OtherArgNo = 0; OtherArgNo < ICS.getNumArgOperands();
+    const auto &CB = cast<CallBase>(getAnchorValue());
+    for (unsigned OtherArgNo = 0; OtherArgNo < CB.getNumArgOperands();
          OtherArgNo++)
-      if (mayAliasWithArgument(A, AAR, MemBehaviorAA, ICS, OtherArgNo))
+      if (mayAliasWithArgument(A, AAR, MemBehaviorAA, CB, OtherArgNo))
         return false;
 
     return true;
   }
 
   /// See AbstractAttribute::updateImpl(...).
   ChangeStatus updateImpl(Attributor &A) override {
     // If the argument is readnone we are done as there are no accesses via the
virtual ChangeStatus updateImpl(Attributor &A) override {
 
     auto CheckReturnValue = [&](Value &RV) -> bool {
       if (Constant *C = dyn_cast<Constant>(&RV))
         if (C->isNullValue() || isa<UndefValue>(C))
           return true;
 
       /// For now, we can only deduce noalias if we have call sites.
       /// FIXME: add more support.
-      ImmutableCallSite ICS(&RV);
-      if (!ICS)
+      const auto *CB = dyn_cast<CallBase>(&RV);
+      if (!CB)
         return false;
 
       const IRPosition &RVPos = IRPosition::value(RV);
       const auto &NoAliasAA = A.getAAFor<AANoAlias>(*this, RVPos);
       if (!NoAliasAA.isAssumedNoAlias())
         return false;
 
       const auto &NoCaptureAA = A.getAAFor<AANoCapture>(*this, RVPos);
bool assumeLive(Attributor &A, const BasicBlock &BB) {
     if (!AssumedLiveBlocks.insert(&BB).second)
       return false;
 
     // We assume that all of BB is (probably) live now and if there are calls to
     // internal functions we will assume that those are now live as well. This
     // is a performance optimization for blocks with calls to a lot of internal
     // functions. It can however cause dead functions to be treated as live.
     for (const Instruction &I : BB)
-      if (ImmutableCallSite ICS = ImmutableCallSite(&I))
-        if (const Function *F = ICS.getCalledFunction())
+      if (const auto *CB = dyn_cast<CallBase>(&I))
+        if (const Function *F = CB->getCalledFunction())
           if (F->hasLocalLinkage())
             A.markLiveInternalFunction(*F);
     return true;
   }
 
   /// Collection of instructions that need to be explored again, e.g., we
   /// did assume they do not transfer control to (one of their) successors.
   SmallSetVector<const Instruction *, 8> ToBeExploredFrom;
static unsigned getKnownAlignForUse(Attributor &A,
   if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
     if (GEP->hasAllConstantIndices()) {
       TrackUse = true;
       return 0;
     }
   }
 
   MaybeAlign MA;
-  if (ImmutableCallSite ICS = ImmutableCallSite(I)) {
-    if (ICS.isBundleOperand(U) || ICS.isCallee(U))
+  if (const auto *CB = dyn_cast<CallBase>(I)) {
+    if (CB->isBundleOperand(U) || CB->isCallee(U))
       return 0;
 
-    unsigned ArgNo = ICS.getArgumentNo(U);
-    IRPosition IRP = IRPosition::callsite_argument(ICS, ArgNo);
+    unsigned ArgNo = CB->getArgOperandNo(U);
+    IRPosition IRP = IRPosition::callsite_argument(*CB, ArgNo);
     // As long as we only use known information there is no need to track
     // dependences here.
     auto &AlignAA = A.getAAFor<AAAlign>(QueryingAA, IRP,
                                         /* TrackDependence */ false);
     MA = MaybeAlign(AlignAA.getKnownAlign());
   }
 
   const DataLayout &DL = A.getDataLayout();
bool captured(const Use *U) override {
 
     // Explicitly catch return instructions.
     if (isa<ReturnInst>(UInst))
       return isCapturedIn(/* Memory */ false, /* Integer */ false,
                           /* Return */ true);
 
     // For now we only use special logic for call sites. However, the tracker
     // itself knows about a lot of other non-capturing cases already.
-    CallSite CS(UInst);
-    if (!CS || !CS.isArgOperand(U))
+    auto *CB = dyn_cast<CallBase>(UInst);
+    if (!CB || !CB->isArgOperand(U))
       return isCapturedIn(/* Memory */ true, /* Integer */ true,
                           /* Return */ true);
 
-    unsigned ArgNo = CS.getArgumentNo(U);
-    const IRPosition &CSArgPos = IRPosition::callsite_argument(CS, ArgNo);
+    unsigned ArgNo = CB->getArgOperandNo(U);
+    const IRPosition &CSArgPos = IRPosition::callsite_argument(*CB, ArgNo);
     // If we have a abstract no-capture attribute for the argument we can use
     // it to justify a non-capture attribute here. This allows recursion!
     auto &ArgNoCaptureAA = A.getAAFor<AANoCapture>(NoCaptureAA, CSArgPos);
     if (ArgNoCaptureAA.isAssumedNoCapture())
       return isCapturedIn(/* Memory */ false, /* Integer */ false,
                           /* Return */ false);
     if (ArgNoCaptureAA.isAssumedNoCaptureMaybeReturned()) {
-      addPotentialCopy(CS);
+      addPotentialCopy(*CB);
       return isCapturedIn(/* Memory */ false, /* Integer */ false,
                           /* Return */ false);
     }
 
     // Lastly, we could not find a reason no-capture can be assumed so we don't.
     return isCapturedIn(/* Memory */ true, /* Integer */ true,
                         /* Return */ true);
   }
 
   /// Register \p CS as potential copy of the value we are checking.
-  void addPotentialCopy(CallSite CS) {
-    PotentialCopies.push_back(CS.getInstruction());
-  }
+  void addPotentialCopy(CallBase &CB) { PotentialCopies.push_back(&CB); }
 
   /// See CaptureTracker::shouldExplore(...).
   bool shouldExplore(const Use *U) override {
     // Check liveness and ignore droppable users.
     return !U->getUser()->isDroppable() &&
            !A.isAssumedDead(*U, &NoCaptureAA, &IsDeadAA);
   }
 
if (!A.isValidFunctionSignatureRewrite(*Arg, ReplacementTypes)) {
       LLVM_DEBUG(dbgs() << "[AAPrivatizablePtr] Rewrite not valid\n");
       return indicatePessimisticFixpoint();
     }
 
     unsigned ArgNo = Arg->getArgNo();
 
     // Helper to check if for the given call site the associated argument is
     // passed to a callback where the privatization would be different.
-    auto IsCompatiblePrivArgOfCallback = [&](CallSite CS) {
+    auto IsCompatiblePrivArgOfCallback = [&](CallBase &CB) {
       SmallVector<const Use *, 4> CallbackUses;
-      AbstractCallSite::getCallbackUses(cast<CallBase>(*CS.getInstruction()),
-                                        CallbackUses);
+      AbstractCallSite::getCallbackUses(CB, CallbackUses);
       for (const Use *U : CallbackUses) {
         AbstractCallSite CBACS(U);
         assert(CBACS && CBACS.isCallbackCall());
         for (Argument &CBArg : CBACS.getCalledFunction()->args()) {
           int CBArgNo = CBACS.getCallArgOperandNo(CBArg);
 
           LLVM_DEBUG({
             dbgs()
                 << "[AAPrivatizablePtr] Argument " << *Arg
                 << "check if can be privatized in the context of its parent ("
                 << Arg->getParent()->getName()
                 << ")\n[AAPrivatizablePtr] because it is an argument in a "
                    "callback ("
                 << CBArgNo << "@" << CBACS.getCalledFunction()->getName()
                 << ")\n[AAPrivatizablePtr] " << CBArg << " : "
                 << CBACS.getCallArgOperand(CBArg) << " vs "
-                << CS.getArgOperand(ArgNo) << "\n"
+                << CB.getArgOperand(ArgNo) << "\n"
                 << "[AAPrivatizablePtr] " << CBArg << " : "
                 << CBACS.getCallArgOperandNo(CBArg) << " vs " << ArgNo << "\n";
           });
 
           if (CBArgNo != int(ArgNo))
             continue;
           const auto &CBArgPrivAA =
               A.getAAFor<AAPrivatizablePtr>(*this, IRPosition::argument(CBArg));
auto IsCompatiblePrivArgOfDirectCS = [&](AbstractCallSite ACS) {
       return false;
     };
 
     // Helper to check if the associated argument is used at the given abstract
     // call site in a way that is incompatible with the privatization assumed
     // here.
     auto IsCompatiblePrivArgOfOtherCallSite = [&](AbstractCallSite ACS) {
       if (ACS.isDirectCall())
-        return IsCompatiblePrivArgOfCallback(CallSite(ACS.getInstruction()));
+        return IsCompatiblePrivArgOfCallback(*ACS.getInstruction());
       if (ACS.isCallbackCall())
         return IsCompatiblePrivArgOfDirectCS(ACS);
       return false;
     };
 
     bool AllCallSitesKnown;
     if (!A.checkForAllCallSites(IsCompatiblePrivArgOfOtherCallSite, *this, true,
                                 AllCallSitesKnown))
ChangeStatus AAMemoryBehaviorFunction::updateImpl(Attributor &A) {
 
   // The current assumed state used to determine a change.
   auto AssumedState = getAssumed();
 
   auto CheckRWInst = [&](Instruction &I) {
     // If the instruction has an own memory behavior state, use it to restrict
     // the local state. No further analysis is required as the other memory
     // state is as optimistic as it gets.
-    if (ImmutableCallSite ICS = ImmutableCallSite(&I)) {
+    if (const auto *CB = dyn_cast<CallBase>(&I)) {
       const auto &MemBehaviorAA = A.getAAFor<AAMemoryBehavior>(
-          *this, IRPosition::callsite_function(ICS));
+          *this, IRPosition::callsite_function(*CB));
       intersectAssumedBits(MemBehaviorAA.getAssumed());
       return !isAtFixpoint();
     }
 
     // Remove access kind modifiers if necessary.
     if (I.mayReadFromMemory())
       removeAssumedBits(NO_READS);
     if (I.mayWriteToMemory())
bool AAMemoryBehaviorFloating::followUsersOfUseIn(Attributor &A, const Use *U,
                                                   const Instruction *UserI) {
   // The loaded value is unrelated to the pointer argument, no need to
   // follow the users of the load.
   if (isa<LoadInst>(UserI))
     return false;
 
   // By default we follow all uses assuming UserI might leak information on U,
   // we have special handling for call sites operands though.
-  ImmutableCallSite ICS(UserI);
-  if (!ICS || !ICS.isArgOperand(U))
+  const auto *CB = dyn_cast<CallBase>(UserI);
+  if (!CB || !CB->isArgOperand(U))
     return true;
 
   // If the use is a call argument known not to be captured, the users of
   // the call do not need to be visited because they have to be unrelated to
   // the input. Note that this check is not trivial even though we disallow
   // general capturing of the underlying argument. The reason is that the
   // call might the argument "through return", which we allow and for which we
   // need to check call users.
   if (U->get()->getType()->isPointerTy()) {
-    unsigned ArgNo = ICS.getArgumentNo(U);
+    unsigned ArgNo = CB->getArgOperandNo(U);
     const auto &ArgNoCaptureAA = A.getAAFor<AANoCapture>(
-        *this, IRPosition::callsite_argument(ICS, ArgNo),
+        *this, IRPosition::callsite_argument(*CB, ArgNo),
         /* TrackDependence */ true, DepClassTy::OPTIONAL);
     return !ArgNoCaptureAA.isAssumedNoCapture();
   }
 
   return true;
 }
 
 void AAMemoryBehaviorFloating::analyzeUseIn(Attributor &A, const Use *U,
if (cast<StoreInst>(UserI)->getPointerOperand() == U->get())
       removeAssumedBits(NO_WRITES);
     return;
 
   case Instruction::Call:
   case Instruction::CallBr:
   case Instruction::Invoke: {
     // For call sites we look at the argument memory behavior attribute (this
     // could be recursive!) in order to restrict our own state.
-    ImmutableCallSite ICS(UserI);
+    const auto *CB = cast<CallBase>(UserI);
 
     // Give up on operand bundles.
-    if (ICS.isBundleOperand(U)) {
+    if (CB->isBundleOperand(U)) {
       indicatePessimisticFixpoint();
       return;
     }
 
     // Calling a function does read the function pointer, maybe write it if the
     // function is self-modifying.
-    if (ICS.isCallee(U)) {
+    if (CB->isCallee(U)) {
       removeAssumedBits(NO_READS);
       break;
     }
 
     // Adjust the possible access behavior based on the information on the
     // argument.
     IRPosition Pos;
     if (U->get()->getType()->isPointerTy())
-      Pos = IRPosition::callsite_argument(ICS, ICS.getArgumentNo(U));
+      Pos = IRPosition::callsite_argument(*CB, CB->getArgOperandNo(U));
     else
-      Pos = IRPosition::callsite_function(ICS);
+      Pos = IRPosition::callsite_function(*CB);
     const auto &MemBehaviorAA = A.getAAFor<AAMemoryBehavior>(
         *this, Pos,
         /* TrackDependence */ true, DepClassTy::OPTIONAL);
     // "assumed" has at most the same bits as the MemBehaviorAA assumed
     // and at least "known".
     intersectAssumedBits(MemBehaviorAA.getAssumed());
     return;
   }
if (auto *GV = dyn_cast<GlobalValue>(&V)) {
                                   NO_GLOBAL_EXTERNAL_MEM, &I, &V, Changed);
       return true;
     }
     if (isa<AllocaInst>(V)) {
       updateStateAndAccessesMap(T, AccessKindAccessesMap, NO_LOCAL_MEM, &I, &V,
                                 Changed);
       return true;
     }
-    if (ImmutableCallSite ICS = ImmutableCallSite(&V)) {
+    if (const auto *CB = dyn_cast<CallBase>(&V)) {
       const auto &NoAliasAA =
-          A.getAAFor<AANoAlias>(*this, IRPosition::callsite_returned(ICS));
+          A.getAAFor<AANoAlias>(*this, IRPosition::callsite_returned(*CB));
       if (NoAliasAA.isAssumedNoAlias()) {
         updateStateAndAccessesMap(T, AccessKindAccessesMap, NO_MALLOCED_MEM, &I,
                                   &V, Changed);
         return true;
       }
     }
 
     updateStateAndAccessesMap(T, AccessKindAccessesMap, NO_UNKOWN_MEM, &I, &V,

 AAMemoryLocationImpl::categorizeAccessedLocations(Attributor &A, Instruction &I,
                                                   bool &Changed) {
   LLVM_DEBUG(dbgs() << "[AAMemoryLocation] Categorize accessed locations for "
                     << I << "\n");
 
   AAMemoryLocation::StateType AccessedLocs;
   AccessedLocs.intersectAssumedBits(NO_LOCATIONS);
 
-  if (ImmutableCallSite ICS = ImmutableCallSite(&I)) {
+  if (auto *CB = dyn_cast<CallBase>(&I)) {
 
     // First check if we assume any memory is access is visible.
-    const auto &ICSMemLocationAA =
-        A.getAAFor<AAMemoryLocation>(*this, IRPosition::callsite_function(ICS));
+    const auto &CBMemLocationAA =
+        A.getAAFor<AAMemoryLocation>(*this, IRPosition::callsite_function(*CB));
     LLVM_DEBUG(dbgs() << "[AAMemoryLocation] Categorize call site: " << I
-                      << " [" << ICSMemLocationAA << "]\n");
+                      << " [" << CBMemLocationAA << "]\n");
 
-    if (ICSMemLocationAA.isAssumedReadNone())
+    if (CBMemLocationAA.isAssumedReadNone())
       return NO_LOCATIONS;
 
-    if (ICSMemLocationAA.isAssumedInaccessibleMemOnly()) {
+    if (CBMemLocationAA.isAssumedInaccessibleMemOnly()) {
       updateStateAndAccessesMap(AccessedLocs, AccessKindAccessesMap,
                                 NO_INACCESSIBLE_MEM, &I, nullptr, Changed);
       return AccessedLocs.getAssumed();
     }
 
-    uint32_t ICSAssumedNotAccessedLocs =
-        ICSMemLocationAA.getAssumedNotAccessedLocation();
+    uint32_t CBAssumedNotAccessedLocs =
+        CBMemLocationAA.getAssumedNotAccessedLocation();
 
     // Set the argmemonly and global bit as we handle them separately below.
-    uint32_t ICSAssumedNotAccessedLocsNoArgMem =
-        ICSAssumedNotAccessedLocs | NO_ARGUMENT_MEM | NO_GLOBAL_MEM;
+    uint32_t CBAssumedNotAccessedLocsNoArgMem =
+        CBAssumedNotAccessedLocs | NO_ARGUMENT_MEM | NO_GLOBAL_MEM;
 
     for (MemoryLocationsKind CurMLK = 1; CurMLK < NO_LOCATIONS; CurMLK *= 2) {
-      if (ICSAssumedNotAccessedLocsNoArgMem & CurMLK)
+      if (CBAssumedNotAccessedLocsNoArgMem & CurMLK)
         continue;
       updateStateAndAccessesMap(AccessedLocs, AccessKindAccessesMap, CurMLK, &I,
                                 nullptr, Changed);
     }
 
     // Now handle global memory if it might be accessed. This is slightly tricky
     // as NO_GLOBAL_MEM has multiple bits set.
-    bool HasGlobalAccesses = ((~ICSAssumedNotAccessedLocs) & NO_GLOBAL_MEM);
+    bool HasGlobalAccesses = ((~CBAssumedNotAccessedLocs) & NO_GLOBAL_MEM);
     if (HasGlobalAccesses) {
       auto AccessPred = [&](const Instruction *, const Value *Ptr,
                             AccessKind Kind, MemoryLocationsKind MLK) {
         updateStateAndAccessesMap(AccessedLocs, AccessKindAccessesMap, MLK, &I,
                                   Ptr, Changed);
         return true;
       };
-      if (!ICSMemLocationAA.checkForAllAccessesToMemoryKind(
+      if (!CBMemLocationAA.checkForAllAccessesToMemoryKind(
               AccessPred, inverseLocation(NO_GLOBAL_MEM, false, false)))
         return AccessedLocs.getWorstState();
     }
 
     LLVM_DEBUG(
         dbgs() << "[AAMemoryLocation] Accessed state before argument handling: "
                << getMemoryLocationsAsStr(AccessedLocs.getAssumed()) << "\n");
 
     // Now handle argument memory if it might be accessed.
-    bool HasArgAccesses = ((~ICSAssumedNotAccessedLocs) & NO_ARGUMENT_MEM);
+    bool HasArgAccesses = ((~CBAssumedNotAccessedLocs) & NO_ARGUMENT_MEM);
     if (HasArgAccesses) {
-      for (unsigned ArgNo = 0, e = ICS.getNumArgOperands(); ArgNo < e;
+      for (unsigned ArgNo = 0, e = CB->getNumArgOperands(); ArgNo < e;
            ++ArgNo) {
 
         // Skip non-pointer arguments.
-        const Value *ArgOp = ICS.getArgOperand(ArgNo);
+        const Value *ArgOp = CB->getArgOperand(ArgNo);
         if (!ArgOp->getType()->isPtrOrPtrVectorTy())
           continue;
 
         // Skip readnone arguments.
-        const IRPosition &ArgOpIRP = IRPosition::callsite_argument(ICS, ArgNo);
+        const IRPosition &ArgOpIRP = IRPosition::callsite_argument(*CB, ArgNo);
         const auto &ArgOpMemLocationAA = A.getAAFor<AAMemoryBehavior>(
             *this, ArgOpIRP, /* TrackDependence */ true, DepClassTy::OPTIONAL);
 
         if (ArgOpMemLocationAA.isAssumedReadNone())
           continue;
 
         // Categorize potentially accessed pointer arguments as if there was an
         // access instruction with them as pointer.

llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp

bool MemCpyOptPass::processMemMove(MemMoveInst *M) {
   // conservatively flush it from the cache.
   MD->removeInstruction(M);
 
   ++NumMoveToCpy;
   return true;
 }
 
 /// This is called on every byval argument in call sites.
-bool MemCpyOptPass::processByValArgument(CallSite CS, unsigned ArgNo) {
-  const DataLayout &DL = CS.getCaller()->getParent()->getDataLayout();
+bool MemCpyOptPass::processByValArgument(CallBase &CB, unsigned ArgNo) {
+  const DataLayout &DL = CB.getCaller()->getParent()->getDataLayout();
   // Find out what feeds this byval argument.
-  Value *ByValArg = CS.getArgument(ArgNo);
+  Value *ByValArg = CB.getArgOperand(ArgNo);
   Type *ByValTy = cast<PointerType>(ByValArg->getType())->getElementType();
   uint64_t ByValSize = DL.getTypeAllocSize(ByValTy);
   MemDepResult DepInfo = MD->getPointerDependencyFrom(
       MemoryLocation(ByValArg, LocationSize::precise(ByValSize)), true,
-      CS.getInstruction()->getIterator(), CS.getInstruction()->getParent());
+      CB.getIterator(), CB.getParent());
   if (!DepInfo.isClobber())
     return false;
 
   // If the byval argument isn't fed by a memcpy, ignore it.  If it is fed by
   // a memcpy, see if we can byval from the source of the memcpy instead of the
   // result.
   MemCpyInst *MDep = dyn_cast<MemCpyInst>(DepInfo.getInst());
   if (!MDep || MDep->isVolatile() ||
       ByValArg->stripPointerCasts() != MDep->getDest())
     return false;
 
   // The length of the memcpy must be larger or equal to the size of the byval.
   ConstantInt *C1 = dyn_cast<ConstantInt>(MDep->getLength());
   if (!C1 || C1->getValue().getZExtValue() < ByValSize)
     return false;
 
   // Get the alignment of the byval.  If the call doesn't specify the alignment,
   // then it is some target specific value that we can't know.
-  unsigned ByValAlign = CS.getParamAlignment(ArgNo);
-  if (ByValAlign == 0) return false;
+  MaybeAlign ByValAlign = CB.getParamAlign(ArgNo);
+  if (!ByValAlign) return false;
 
   // If it is greater than the memcpy, then we check to see if we can force the
   // source of the memcpy to the alignment we need.  If we fail, we bail out.
   AssumptionCache &AC = LookupAssumptionCache();
   DominatorTree &DT = LookupDomTree();
-  if (MDep->getSourceAlignment() < ByValAlign &&
-      getOrEnforceKnownAlignment(MDep->getSource(), ByValAlign, DL,
-                                 CS.getInstruction(), &AC, &DT) < ByValAlign)
+  if (MDep->getSourceAlign() < ByValAlign &&
+      getOrEnforceKnownAlignment(MDep->getSource(), ByValAlign->value(), DL,
+                                 &CB, &AC, &DT) < ByValAlign->value())
     return false;
 
   // The address space of the memcpy source must match the byval argument
   if (MDep->getSource()->getType()->getPointerAddressSpace() !=
       ByValArg->getType()->getPointerAddressSpace())
     return false;
 
   // Verify that the copied-from memory doesn't change in between the memcpy and
   // the byval call.
   //    memcpy(a <- b)
   //    *b = 42;
   //    foo(*a)
   // It would be invalid to transform the second memcpy into foo(*b).
   //
   // NOTE: This is conservative, it will stop on any read from the source loc,
   // not just the defining memcpy.
   MemDepResult SourceDep = MD->getPointerDependencyFrom(
       MemoryLocation::getForSource(MDep), false,
-      CS.getInstruction()->getIterator(), MDep->getParent());
+      CB.getIterator(), MDep->getParent());
   if (!SourceDep.isClobber() || SourceDep.getInst() != MDep)
     return false;
 
   Value *TmpCast = MDep->getSource();
   if (MDep->getSource()->getType() != ByValArg->getType()) {
     BitCastInst *TmpBitCast = new BitCastInst(MDep->getSource(), ByValArg->getType(),
-                                              "tmpcast", CS.getInstruction());
+                                              "tmpcast", &CB);
     // Set the tmpcast's DebugLoc to MDep's
     TmpBitCast->setDebugLoc(MDep->getDebugLoc());
     TmpCast = TmpBitCast;
   }
 
   LLVM_DEBUG(dbgs() << "MemCpyOptPass: Forwarding memcpy to byval:\n"
                     << "  " << *MDep << "\n"
-                    << "  " << *CS.getInstruction() << "\n");
+                    << "  " << CB << "\n");
 
   // Otherwise we're good!  Update the byval argument.
-  CS.setArgument(ArgNo, TmpCast);
+  CB.setArgOperand(ArgNo, TmpCast);
   ++NumMemCpyInstr;
   return true;
 }
 
 /// Executes one iteration of MemCpyOptPass.
 bool MemCpyOptPass::iterateOnFunction(Function &F) {
   bool MadeChange = false;
 
for (BasicBlock::iterator BI = BB.begin(), BE = BB.end(); BI != BE;) {
       if (StoreInst *SI = dyn_cast<StoreInst>(I))
         MadeChange |= processStore(SI, BI);
       else if (MemSetInst *M = dyn_cast<MemSetInst>(I))
         RepeatInstruction = processMemSet(M, BI);
       else if (MemCpyInst *M = dyn_cast<MemCpyInst>(I))
         RepeatInstruction = processMemCpy(M);
       else if (MemMoveInst *M = dyn_cast<MemMoveInst>(I))
         RepeatInstruction = processMemMove(M);
-      else if (auto CS = CallSite(I)) {
-        for (unsigned i = 0, e = CS.arg_size(); i != e; ++i)
-          if (CS.isByValArgument(i))
-            MadeChange |= processByValArgument(CS, i);
+      else if (auto *CB = dyn_cast<CallBase>(I)) {
+        for (unsigned I = 0, E = CB->arg_size(); I != E; ++I)
+          if (CB->isByValArgument(I))
+            MadeChange |= processByValArgument(*CB, I);
       }
 
       // Reprocess the instruction if desired.
       if (RepeatInstruction) {
         if (BI != BB.begin())
           --BI;
         MadeChange = true;
       }