[NFC][PowerPC] Small code refactor in LoopInstrFormPrep

[jsji]

Summary

Avoid some duplicate code.

[shchenz]

LGTM.

Thanks for doing this. I was about to commit an NFC patch for the format issues in https://reviews.llvm.org/D108750 and https://reviews.llvm.org/D105872 including this function refactor.

llvm/lib/Target/PowerPC/PPCLoopInstrFormPrep.cpp

272

We need to fix the clang-tidy warning. And we can not just use getPointerOperand() as the load/store instruction also has a member function named by getPointerOperand.

[jsji]

Rename

llvm/lib/Target/PowerPC/PPCLoopInstrFormPrep.cpp

 static std::string getInstrName(const Value *I, StringRef Suffix) {
   assert(I && "Invalid paramater!");
   if (I->hasName())
     return (I->getName() + Suffix).str();
   else
     return ""; 
 }
 
-static Value *GetPointerOperand(Value *MemI) {
+static Value *GetPointerOperand(Value *MemI, Type **PtrElementType = nullptr) {
+
+  Value *PtrValue = nullptr;
+  Type *PointerElementType = nullptr;
+
   if (LoadInst *LMemI = dyn_cast<LoadInst>(MemI)) {
-    return LMemI->getPointerOperand();
+    PtrValue = LMemI->getPointerOperand();
+    PointerElementType = LMemI->getType();
   } else if (StoreInst *SMemI = dyn_cast<StoreInst>(MemI)) {
-    return SMemI->getPointerOperand();
+    PtrValue = SMemI->getPointerOperand();
+    PointerElementType = SMemI->getValueOperand()->getType();
   } else if (IntrinsicInst *IMemI = dyn_cast<IntrinsicInst>(MemI)) {
+    PointerElementType = Type::getInt8Ty(MemI->getContext());
     if (IMemI->getIntrinsicID() == Intrinsic::prefetch ||
-        IMemI->getIntrinsicID() == Intrinsic::ppc_vsx_lxvp)
-      return IMemI->getArgOperand(0);
-    if (IMemI->getIntrinsicID() == Intrinsic::ppc_vsx_stxvp)
-      return IMemI->getArgOperand(1);
+        IMemI->getIntrinsicID() == Intrinsic::ppc_vsx_lxvp) {
+      PtrValue = IMemI->getArgOperand(0);
+    } else if (IMemI->getIntrinsicID() == Intrinsic::ppc_vsx_stxvp) {
+      PtrValue = IMemI->getArgOperand(1);
+    }
   }
+  /*Get ElementType if PtrElementType is not null.*/
+  if (PtrElementType)
+    *PtrElementType = PointerElementType;
 
-  return nullptr;
+  return PtrValue;
 }
 
 bool PPCLoopInstrFormPrep::runOnFunction(Function &F) {
   if (skipFunction(F))
     return false;
 
   LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
   SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();

 SmallVector<Bucket, 16> PPCLoopInstrFormPrep::collectCandidates(
     Loop *L,
     std::function<bool(const Instruction *, const Value *, const Type *)>
         isValidCandidate,
     unsigned MaxCandidateNum) {
   SmallVector<Bucket, 16> Buckets;
   for (const auto &BB : L->blocks())
     for (auto &J : *BB) {
-      Value *PtrValue;
-      Type *PointerElementType;
+      Value *PtrValue = nullptr;
+      Type *PointerElementType = nullptr;
+      PtrValue = GetPointerOperand(&J, &PointerElementType);
 
-      if (LoadInst *LMemI = dyn_cast<LoadInst>(&J)) {
-        PtrValue = LMemI->getPointerOperand();
-        PointerElementType = LMemI->getType();
-      } else if (StoreInst *SMemI = dyn_cast<StoreInst>(&J)) {
-        PtrValue = SMemI->getPointerOperand();
-        PointerElementType = SMemI->getValueOperand()->getType();
-      } else if (IntrinsicInst *IMemI = dyn_cast<IntrinsicInst>(&J)) {
-        PointerElementType = Type::getInt8Ty(J.getContext());
-        if (IMemI->getIntrinsicID() == Intrinsic::prefetch ||
-            IMemI->getIntrinsicID() == Intrinsic::ppc_vsx_lxvp) {
-          PtrValue = IMemI->getArgOperand(0);
-        } else if (IMemI->getIntrinsicID() == Intrinsic::ppc_vsx_stxvp) {
-          PtrValue = IMemI->getArgOperand(1);
-        } else continue;
-      } else continue;
+      if (!PtrValue)
+        continue;
 
-      unsigned PtrAddrSpace = PtrValue->getType()->getPointerAddressSpace();
-      if (PtrAddrSpace)
+      if (PtrValue->getType()->getPointerAddressSpace())
         continue;
 
       if (L->isLoopInvariant(PtrValue))
         continue;
 
       const SCEV *LSCEV = SE->getSCEVAtScope(PtrValue, L);
       const SCEVAddRecExpr *LARSCEV = dyn_cast<SCEVAddRecExpr>(LSCEV);
       if (!LARSCEV || LARSCEV->getLoop() != L)