NFC: Pass DataLayout into isBytewiseValue

[vitalybuka]

Summary

We will need to handle IntToPtr which I will submit in a separate patch as it's
not going to be NFC.

[eugenis]

LGTM

clang/lib/CodeGen/CGDecl.cpp

 }
 
 /// Decide whether we should use memset to initialize a local variable instead
 /// of using a memcpy from a constant global. Assumes we've already decided to
 /// not user bzero.
 /// FIXME We could be more clever, as we are for bzero above, and generate
 ///       memset followed by stores. It's unclear that's worth the effort.
 static llvm::Value *shouldUseMemSetToInitialize(llvm::Constant *Init,
-                                                uint64_t GlobalSize) {
+                                                uint64_t GlobalSize,
+                                                const llvm::DataLayout &DL) {
   uint64_t SizeLimit = 32;
   if (GlobalSize <= SizeLimit)
     return nullptr;
-  return llvm::isBytewiseValue(Init);
+  return llvm::isBytewiseValue(Init, DL);
 }
 
 /// Decide whether we want to split a constant structure or array store into a
 /// sequence of its fields' stores. This may cost us code size and compilation
 /// speed, but plays better with store optimizations.
 static bool shouldSplitConstantStore(CodeGenModule &CGM,
                                      uint64_t GlobalByteSize) {
   // Don't break things that occupy more than one cacheline.
if (shouldUseBZeroPlusStoresToInitialize(constant, ConstantSize)) {
     if (!valueAlreadyCorrect) {
       Loc = Builder.CreateBitCast(Loc, Ty->getPointerTo(Loc.getAddressSpace()));
       emitStoresForInitAfterBZero(CGM, constant, Loc, isVolatile, Builder);
     }
     return;
   }
 
   // If the initializer is a repeated byte pattern, use memset.
-  llvm::Value *Pattern = shouldUseMemSetToInitialize(constant, ConstantSize);
+  llvm::Value *Pattern =
+      shouldUseMemSetToInitialize(constant, ConstantSize, CGM.getDataLayout());
   if (Pattern) {
     uint64_t Value = 0x00;
     if (!isa<llvm::UndefValue>(Pattern)) {
       const llvm::APInt &AP = cast<llvm::ConstantInt>(Pattern)->getValue();
       assert(AP.getBitWidth() <= 8);
       Value = AP.getLimitedValue();
     }
     Builder.CreateMemSet(Loc, llvm::ConstantInt::get(CGM.Int8Ty, Value), SizeVal,

llvm/include/llvm/Analysis/ValueTracking.h

class Value;
   bool SignBitMustBeZero(const Value *V, const TargetLibraryInfo *TLI);
 
   /// If the specified value can be set by repeating the same byte in memory,
   /// return the i8 value that it is represented with. This is true for all i8
   /// values obviously, but is also true for i32 0, i32 -1, i16 0xF0F0, double
   /// 0.0 etc. If the value can't be handled with a repeated byte store (e.g.
   /// i16 0x1234), return null. If the value is entirely undef and padding,
   /// return undef.
-  Value *isBytewiseValue(Value *V);
+  Value *isBytewiseValue(Value *V, const DataLayout &DL);
 
   /// Given an aggregrate and an sequence of indices, see if the scalar value
   /// indexed is already around as a register, for example if it were inserted
   /// directly into the aggregrate.
   ///
   /// If InsertBefore is not null, this function will duplicate (modified)
   /// insertvalues when a part of a nested struct is extracted.
   Value *FindInsertedValue(Value *V,

llvm/lib/Analysis/ValueTracking.cpp

for (unsigned i = 0; i != NumElts; ++i) {
     auto *CElt = dyn_cast<ConstantFP>(Elt);
     if (!CElt || CElt->isNaN())
       return false;
   }
   // All elements were confirmed not-NaN or undefined.
   return true;
 }
 
-Value *llvm::isBytewiseValue(Value *V) {
+Value *llvm::isBytewiseValue(Value *V, const DataLayout &DL) {
 
   // All byte-wide stores are splatable, even of arbitrary variables.
   if (V->getType()->isIntegerTy(8))
     return V;
 
   LLVMContext &Ctx = V->getContext();
 
   // Undef don't care.
if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
     Type *Ty = nullptr;
     if (CFP->getType()->isHalfTy())
       Ty = Type::getInt16Ty(Ctx);
     else if (CFP->getType()->isFloatTy())
       Ty = Type::getInt32Ty(Ctx);
     else if (CFP->getType()->isDoubleTy())
       Ty = Type::getInt64Ty(Ctx);
     // Don't handle long double formats, which have strange constraints.
-    return Ty ? isBytewiseValue(ConstantExpr::getBitCast(CFP, Ty)) : nullptr;
+    return Ty ? isBytewiseValue(ConstantExpr::getBitCast(CFP, Ty), DL)
+              : nullptr;
   }
 
   // We can handle constant integers that are multiple of 8 bits.
   if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
     if (CI->getBitWidth() % 8 == 0) {
       assert(CI->getBitWidth() > 8 && "8 bits should be handled above!");
       if (!CI->getValue().isSplat(8))
         return nullptr;
auto Merge = [&](Value *LHS, Value *RHS) -> Value * {
     if (RHS == UndefInt8)
       return LHS;
     return nullptr;
   };
 
   if (ConstantDataSequential *CA = dyn_cast<ConstantDataSequential>(C)) {
     Value *Val = UndefInt8;
     for (unsigned I = 0, E = CA->getNumElements(); I != E; ++I)
-      if (!(Val = Merge(Val, isBytewiseValue(CA->getElementAsConstant(I)))))
+      if (!(Val = Merge(Val, isBytewiseValue(CA->getElementAsConstant(I), DL))))
         return nullptr;
     return Val;
   }
 
   if (isa<ConstantVector>(C)) {
     Constant *Splat = cast<ConstantVector>(C)->getSplatValue();
-    return Splat ? isBytewiseValue(Splat) : nullptr;
+    return Splat ? isBytewiseValue(Splat, DL) : nullptr;
   }
 
   if (isa<ConstantArray>(C) || isa<ConstantStruct>(C)) {
     Value *Val = UndefInt8;
     for (unsigned I = 0, E = C->getNumOperands(); I != E; ++I)
-      if (!(Val = Merge(Val, isBytewiseValue(C->getOperand(I)))))
+      if (!(Val = Merge(Val, isBytewiseValue(C->getOperand(I), DL))))
         return nullptr;
     return Val;
   }
 
   // Don't try to handle the handful of other constants.
   return nullptr;
 }
 

llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

if (!isa<SCEVConstant>(StoreEv->getOperand(1)))
     return LegalStoreKind::None;
 
   // See if the store can be turned into a memset.
 
   // If the stored value is a byte-wise value (like i32 -1), then it may be
   // turned into a memset of i8 -1, assuming that all the consecutive bytes
   // are stored.  A store of i32 0x01020304 can never be turned into a memset,
   // but it can be turned into memset_pattern if the target supports it.
-  Value *SplatValue = isBytewiseValue(StoredVal);
+  Value *SplatValue = isBytewiseValue(StoredVal, *DL);
   Constant *PatternValue = nullptr;
 
   // Note: memset and memset_pattern on unordered-atomic is yet not supported
   bool UnorderedAtomic = SI->isUnordered() && !SI->isSimple();
 
   // If we're allowed to form a memset, and the stored value would be
   // acceptable for memset, use it.
   if (!UnorderedAtomic && HasMemset && SplatValue &&
if (FirstStride == FirstStoreSize || -FirstStride == FirstStoreSize) {
       Heads.insert(SL[i]);
       continue;
     }
 
     Value *FirstSplatValue = nullptr;
     Constant *FirstPatternValue = nullptr;
 
     if (For == ForMemset::Yes)
-      FirstSplatValue = isBytewiseValue(FirstStoredVal);
+      FirstSplatValue = isBytewiseValue(FirstStoredVal, *DL);
     else
       FirstPatternValue = getMemSetPatternValue(FirstStoredVal, DL);
 
     assert((FirstSplatValue || FirstPatternValue) &&
            "Expected either splat value or pattern value.");
 
     IndexQueue.clear();
     // If a store has multiple consecutive store candidates, search Stores
for (auto &k : IndexQueue) {
       if (FirstStride != SecondStride)
         continue;
 
       Value *SecondStoredVal = SL[k]->getValueOperand();
       Value *SecondSplatValue = nullptr;
       Constant *SecondPatternValue = nullptr;
 
       if (For == ForMemset::Yes)
-        SecondSplatValue = isBytewiseValue(SecondStoredVal);
+        SecondSplatValue = isBytewiseValue(SecondStoredVal, *DL);
       else
         SecondPatternValue = getMemSetPatternValue(SecondStoredVal, DL);
 
       assert((SecondSplatValue || SecondPatternValue) &&
              "Expected either splat value or pattern value.");
 
       if (isConsecutiveAccess(SL[i], SL[k], *DL, *SE, false)) {
         if (For == ForMemset::Yes) {

 
 /// processLoopStridedStore - We see a strided store of some value.  If we can
 /// transform this into a memset or memset_pattern in the loop preheader, do so.
 bool LoopIdiomRecognize::processLoopStridedStore(
     Value *DestPtr, unsigned StoreSize, unsigned StoreAlignment,
     Value *StoredVal, Instruction *TheStore,
     SmallPtrSetImpl<Instruction *> &Stores, const SCEVAddRecExpr *Ev,
     const SCEV *BECount, bool NegStride, bool IsLoopMemset) {
-  Value *SplatValue = isBytewiseValue(StoredVal);
+  Value *SplatValue = isBytewiseValue(StoredVal, *DL);
   Constant *PatternValue = nullptr;
 
   if (!SplatValue)
     PatternValue = getMemSetPatternValue(StoredVal, DL);
 
   assert((SplatValue || PatternValue) &&
          "Expected either splat value or pattern value.");
 

llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp

if (!isa<StoreInst>(BI) && !isa<MemSetInst>(BI)) {
       continue;
     }
 
     if (StoreInst *NextStore = dyn_cast<StoreInst>(BI)) {
       // If this is a store, see if we can merge it in.
       if (!NextStore->isSimple()) break;
 
       // Check to see if this stored value is of the same byte-splattable value.
-      Value *StoredByte = isBytewiseValue(NextStore->getOperand(0));
+      Value *StoredByte = isBytewiseValue(NextStore->getOperand(0), DL);
       if (isa<UndefValue>(ByteVal) && StoredByte)
         ByteVal = StoredByte;
       if (ByteVal != StoredByte)
         break;
 
       // Check to see if this store is to a constant offset from the start ptr.
       int64_t Offset;
       if (!IsPointerOffset(StartPtr, NextStore->getPointerOperand(), Offset,
bool MemCpyOptPass::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
 
   // There are two cases that are interesting for this code to handle: memcpy
   // and memset.  Right now we only handle memset.
 
   // Ensure that the value being stored is something that can be memset'able a
   // byte at a time like "0" or "-1" or any width, as well as things like
   // 0xA0A0A0A0 and 0.0.
   auto *V = SI->getOperand(0);
-  if (Value *ByteVal = isBytewiseValue(V)) {
+  if (Value *ByteVal = isBytewiseValue(V, DL)) {
     if (Instruction *I = tryMergingIntoMemset(SI, SI->getPointerOperand(),
                                               ByteVal)) {
       BBI = I->getIterator(); // Don't invalidate iterator.
       return true;
     }
 
     // If we have an aggregate, we try to promote it to memset regardless
     // of opportunity for merging as it can expose optimization opportunities
if (M->getSource() == M->getDest()) {
     MD->removeInstruction(M);
     M->eraseFromParent();
     return false;
   }
 
   // If copying from a constant, try to turn the memcpy into a memset.
   if (GlobalVariable *GV = dyn_cast<GlobalVariable>(M->getSource()))
     if (GV->isConstant() && GV->hasDefinitiveInitializer())
-      if (Value *ByteVal = isBytewiseValue(GV->getInitializer())) {
+      if (Value *ByteVal = isBytewiseValue(GV->getInitializer(),
+                                           M->getModule()->getDataLayout())) {
         IRBuilder<> Builder(M);
         Builder.CreateMemSet(M->getRawDest(), ByteVal, M->getLength(),
                              M->getDestAlignment(), false);
         MD->removeInstruction(M);
         M->eraseFromParent();
         ++NumCpyToSet;
         return true;
       }