[SYCL] [NATIVECPU] Check null pointer after dyn cast (#11930)

Author: PietroGhg

llvm/lib/SYCLLowerIR/PrepareSYCLNativeCPU.cpp

@@ -295,7 +295,7 @@ static Function *addReplaceFunc(Module &M, StringRef Name, Type *StateType) {
   Type *PtrTy = PointerType::get(Ctx, NativeCPUGlobalAS);
   static FunctionType *FTy = FunctionType::get(RetTy, {DimTy, PtrTy}, false);
   auto FCallee = M.getOrInsertFunction(Name, FTy);
-  auto *F = dyn_cast<Function>(FCallee.getCallee());
+  auto *F = cast<Function>(FCallee.getCallee());
   IRBuilder<> Builder(Ctx);
   BasicBlock *BB = BasicBlock::Create(Ctx, "entry", F);
   Builder.SetInsertPoint(BB);
@@ -366,9 +366,7 @@ PreservedAnalyses PrepareSYCLNativeCPUPass::run(Module &M,
     if (!Glob)
       continue;
     for (const auto &Use : Glob->uses()) {
-      auto I = dyn_cast<CallInst>(Use.getUser());
-      if (!I)
-        report_fatal_error("Unsupported Value in SYCL Native CPU\n");
+      auto *I = cast<CallInst>(Use.getUser());
       if (!IsNativeCPUKernel(I->getFunction())) {
         // only use the threadlocal if we have kernels calling builtins
         // indirectly
@@ -417,9 +415,7 @@ PreservedAnalyses PrepareSYCLNativeCPUPass::run(Module &M,
     Function *const Glob = Entry.first;
     for (const auto &Use : Glob->uses()) {
       auto *ReplaceFunc = getReplaceFunc(M, Entry.second.first, StateType);
-      auto I = dyn_cast<CallInst>(Use.getUser());
-      if (!I)
-        report_fatal_error("Unsupported Value in SYCL Native CPU\n");
+      auto *I = cast<CallInst>(Use.getUser());
       auto *Arg = ConstantInt::get(Type::getInt32Ty(M.getContext()),
                                    Entry.second.second);
       auto *NewI = CallInst::Create(