Relax trivial cast requirements in CallPromotionUtils

[scott.linder]

Summary

Broken out of https://reviews.llvm.org/D52741

Once that is committed there will be some tests exercising the change, but I can also update the PGO tests to prove the change if needed.

[scott.linder]

Sorry, moved a little fast and grabbed the wrong patch at first.

[arsenm]

LGTM. I think it should be possible to come up with a test using IndirectCallPromotion

[scott.linder]

Add test using IndirectCallPromotion

[scott.linder]

Remove -debug flag from test

lib/Transforms/Utils/CallPromotionUtils.cpp

static void createRetBitCast(CallSite CS, Type *RetTy, CastInst **RetBitCast) {
   Instruction *InsertBefore = nullptr;
   if (auto *Invoke = dyn_cast<InvokeInst>(CS.getInstruction()))
     InsertBefore =
         &SplitEdge(Invoke->getParent(), Invoke->getNormalDest())->front();
   else
     InsertBefore = &*std::next(CS.getInstruction()->getIterator());
 
   // Bitcast the return value to the correct type.
-  auto *Cast = CastInst::Create(Instruction::BitCast, CS.getInstruction(),
-                                RetTy, "", InsertBefore);
+  auto *Cast = CastInst::CreateBitOrPointerCast(CS.getInstruction(), RetTy, "",
+                                                InsertBefore);
   if (RetBitCast)
     *RetBitCast = Cast;
 
   // Replace all the original uses of the calling instruction with the bitcast.
   for (User *U : UsersToUpdate)
     U->replaceUsesOfWith(CS.getInstruction(), Cast);
 }
 
static Instruction *versionCallSite(CallSite CS, Value *Callee,
 
   return NewInst;
 }
 
 bool llvm::isLegalToPromote(CallSite CS, Function *Callee,
                             const char **FailureReason) {
   assert(!CS.getCalledFunction() && "Only indirect call sites can be promoted");
 
+  auto &DL = Callee->getParent()->getDataLayout();
+
   // Check the return type. The callee's return value type must be bitcast
   // compatible with the call site's type.
   Type *CallRetTy = CS.getInstruction()->getType();
   Type *FuncRetTy = Callee->getReturnType();
   if (CallRetTy != FuncRetTy)
-    if (!CastInst::isBitCastable(FuncRetTy, CallRetTy)) {
+    if (!CastInst::isBitOrNoopPointerCastable(FuncRetTy, CallRetTy, DL)) {
       if (FailureReason)
         *FailureReason = "Return type mismatch";
       return false;
     }
 
   // The number of formal arguments of the callee.
   unsigned NumParams = Callee->getFunctionType()->getNumParams();
 
   // Check the number of arguments. The callee and call site must agree on the
   // number of arguments.
   if (CS.arg_size() != NumParams && !Callee->isVarArg()) {
     if (FailureReason)
       *FailureReason = "The number of arguments mismatch";
     return false;
   }
 
   // Check the argument types. The callee's formal argument types must be
   // bitcast compatible with the corresponding actual argument types of the call
   // site.
   for (unsigned I = 0; I < NumParams; ++I) {
     Type *FormalTy = Callee->getFunctionType()->getFunctionParamType(I);
     Type *ActualTy = CS.getArgument(I)->getType();
     if (FormalTy == ActualTy)
       continue;
-    if (!CastInst::isBitCastable(ActualTy, FormalTy)) {
+    if (!CastInst::isBitOrNoopPointerCastable(ActualTy, FormalTy, DL)) {
       if (FailureReason)
         *FailureReason = "Argument type mismatch";
       return false;
     }
   }
 
   return true;
 }
Instruction *llvm::promoteCall(CallSite CS, Function *Callee,
   // to the correct type.
   auto CalleeType = Callee->getFunctionType();
   auto CalleeParamNum = CalleeType->getNumParams();
   for (unsigned ArgNo = 0; ArgNo < CalleeParamNum; ++ArgNo) {
     auto *Arg = CS.getArgument(ArgNo);
     Type *FormalTy = CalleeType->getParamType(ArgNo);
     Type *ActualTy = Arg->getType();
     if (FormalTy != ActualTy) {
-      auto *Cast = CastInst::Create(Instruction::BitCast, Arg, FormalTy, "",
+      auto *Cast = CastInst::CreateBitOrPointerCast(Arg, FormalTy, "",
                                                     CS.getInstruction());
       CS.setArgument(ArgNo, Cast);
     }
   }
 
   // If the return type of the call site doesn't match that of the callee, cast
   // the returned value to the appropriate type.
   if (!CallSiteRetTy->isVoidTy() && CallSiteRetTy != CalleeRetTy)
     createRetBitCast(CS, CallSiteRetTy, RetBitCast);