[llvm] Remove no-op ptr-to-ptr bitcasts (NFC) (#72133)

Opaque ptr cleanup effort (NFC).

Author: JOE1994

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

@@ -4494,7 +4494,7 @@ Constant *OpenMPIRBuilder::createOutlinedFunctionID(Function *OutlinedFn,
                                                     StringRef EntryFnIDName) {
   if (Config.isTargetDevice()) {
     assert(OutlinedFn && "The outlined function must exist if embedded");
-    return ConstantExpr::getBitCast(OutlinedFn, Builder.getInt8PtrTy());
+    return OutlinedFn;
   }
 
   return new GlobalVariable(

llvm/lib/IR/Module.cpp

@@ -156,12 +156,6 @@ FunctionCallee Module::getOrInsertFunction(StringRef Name, FunctionType *Ty,
     return {Ty, New}; // Return the new prototype.
   }
 
-  // If the function exists but has the wrong type, return a bitcast to the
-  // right type.
-  auto *PTy = PointerType::get(Ty, F->getAddressSpace());
-  if (F->getType() != PTy)
-    return {Ty, ConstantExpr::getBitCast(F, PTy)};
-
   // Otherwise, we just found the existing function or a prototype.
   return {Ty, F};
 }
@@ -212,13 +206,6 @@ Constant *Module::getOrInsertGlobal(
     GV = CreateGlobalCallback();
   assert(GV && "The CreateGlobalCallback is expected to create a global");
 
-  // If the variable exists but has the wrong type, return a bitcast to the
-  // right type.
-  Type *GVTy = GV->getType();
-  PointerType *PTy = PointerType::get(Ty, GVTy->getPointerAddressSpace());
-  if (GVTy != PTy)
-    return ConstantExpr::getBitCast(GV, PTy);
-
   // Otherwise, we just found the existing function or a prototype.
   return GV;
 }

llvm/lib/LTO/LTO.cpp

@@ -1260,7 +1260,7 @@ Error LTO::runRegularLTO(AddStreamFn AddStream) {
                                   ConstantAggregateZero::get(Ty), "");
     GV->setAlignment(I.second.Alignment);
     if (OldGV) {
-      OldGV->replaceAllUsesWith(ConstantExpr::getBitCast(GV, OldGV->getType()));
+      OldGV->replaceAllUsesWith(GV);
       GV->takeName(OldGV);
       OldGV->eraseFromParent();
     } else {

llvm/lib/Transforms/CFGuard/CFGuard.cpp

@@ -195,11 +195,6 @@ void CFGuard::insertCFGuardDispatch(CallBase *CB) {
   Value *CalledOperand = CB->getCalledOperand();
   Type *CalledOperandType = CalledOperand->getType();
 
-  // Cast the guard dispatch global to the type of the called operand.
-  PointerType *PTy = PointerType::get(CalledOperandType, 0);
-  if (GuardFnGlobal->getType() != PTy)
-    GuardFnGlobal = ConstantExpr::getBitCast(GuardFnGlobal, PTy);
-
   // Load the global as a pointer to a function of the same type.
   LoadInst *GuardDispatchLoad = B.CreateLoad(CalledOperandType, GuardFnGlobal);
 

llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp

@@ -65,9 +65,7 @@ static void insertCall(Function &CurFn, StringRef Func,
         InsertionPt);
     RetAddr->setDebugLoc(DL);
 
-    Value *Args[] = {
-        ConstantExpr::getBitCast(&CurFn, PointerType::getUnqual(C)), RetAddr};
-
+    Value *Args[] = {&CurFn, RetAddr};
     CallInst *Call =
         CallInst::Create(Fn, ArrayRef<Value *>(Args), "", InsertionPt);
     Call->setDebugLoc(DL);