[NFC][LoopIdiom] rename boolean variable NegStride to IsNegStride

[eopXD]

Summary

Rename variable for better code readability.

[eopXD]

Fix clang-format warnings.

llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

private:
   bool processLoopMemCpy(MemCpyInst *MCI, const SCEV *BECount);
   bool processLoopMemSet(MemSetInst *MSI, const SCEV *BECount);
 
   bool processLoopStridedStore(Value *DestPtr, const SCEV *StoreSizeSCEV,
                                MaybeAlign StoreAlignment, Value *StoredVal,
                                Instruction *TheStore,
                                SmallPtrSetImpl<Instruction *> &Stores,
                                const SCEVAddRecExpr *Ev, const SCEV *BECount,
-                               bool NegStride, bool IsLoopMemset = false);
+                               bool IsNegStride, bool IsLoopMemset = false);
   bool processLoopStoreOfLoopLoad(StoreInst *SI, const SCEV *BECount);
   bool processLoopStoreOfLoopLoad(Value *DestPtr, Value *SourcePtr,
                                   unsigned StoreSize, MaybeAlign StoreAlign,
                                   MaybeAlign LoadAlign, Instruction *TheStore,
                                   Instruction *TheLoad,
                                   const SCEVAddRecExpr *StoreEv,
                                   const SCEVAddRecExpr *LoadEv,
                                   const SCEV *BECount);
for (SetVector<StoreInst *>::iterator it = Heads.begin(), e = Heads.end();
     const SCEVAddRecExpr *StoreEv = cast<SCEVAddRecExpr>(SE->getSCEV(StorePtr));
     APInt Stride = getStoreStride(StoreEv);
 
     // Check to see if the stride matches the size of the stores.  If so, then
     // we know that every byte is touched in the loop.
     if (StoreSize != Stride && StoreSize != -Stride)
       continue;
 
-    bool NegStride = StoreSize == -Stride;
+    bool IsNegStride = StoreSize == -Stride;
 
     const SCEV *StoreSizeSCEV = SE->getConstant(BECount->getType(), StoreSize);
     if (processLoopStridedStore(StorePtr, StoreSizeSCEV,
                                 MaybeAlign(HeadStore->getAlignment()),
                                 StoredVal, HeadStore, AdjacentStores, StoreEv,
-                                BECount, NegStride)) {
+                                BECount, IsNegStride)) {
       TransformedStores.insert(AdjacentStores.begin(), AdjacentStores.end());
       Changed = true;
     }
   }
 
   return Changed;
 }
 
bool LoopIdiomRecognize::processLoopMemSet(MemSetInst *MSI,
   // Verify that the memset value is loop invariant.  If not, we can't promote
   // the memset.
   Value *SplatValue = MSI->getValue();
   if (!SplatValue || !CurLoop->isLoopInvariant(SplatValue))
     return false;
 
   SmallPtrSet<Instruction *, 1> MSIs;
   MSIs.insert(MSI);
-  bool NegStride = SizeInBytes == -Stride;
+  bool IsNegStride = SizeInBytes == -Stride;
   return processLoopStridedStore(Pointer, SE->getSCEV(MSI->getLength()),
                                  MaybeAlign(MSI->getDestAlignment()),
-                                 SplatValue, MSI, MSIs, Ev, BECount, NegStride,
-                                 /*IsLoopMemset=*/true);
+                                 SplatValue, MSI, MSIs, Ev, BECount,
+                                 IsNegStride, /*IsLoopMemset=*/true);
 }
 
 /// mayLoopAccessLocation - Return true if the specified loop might access the
 /// specified pointer location, which is a loop-strided access.  The 'Access'
 /// argument specifies what the verboten forms of access are (read or write).
 static bool
 mayLoopAccessLocation(Value *Ptr, ModRefInfo Access, Loop *L,
                       const SCEV *BECount, const SCEV *StoreSizeSCEV,

 }
 
 /// 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, const SCEV *StoreSizeSCEV, MaybeAlign StoreAlignment,
     Value *StoredVal, Instruction *TheStore,
     SmallPtrSetImpl<Instruction *> &Stores, const SCEVAddRecExpr *Ev,
-    const SCEV *BECount, bool NegStride, bool IsLoopMemset) {
+    const SCEV *BECount, bool IsNegStride, bool IsLoopMemset) {
   Value *SplatValue = isBytewiseValue(StoredVal, *DL);
   Constant *PatternValue = nullptr;
 
   if (!SplatValue)
     PatternValue = getMemSetPatternValue(StoredVal, DL);
 
   assert((SplatValue || PatternValue) &&
          "Expected either splat value or pattern value.");
 
   // The trip count of the loop and the base pointer of the addrec SCEV is
   // guaranteed to be loop invariant, which means that it should dominate the
   // header.  This allows us to insert code for it in the preheader.
   unsigned DestAS = DestPtr->getType()->getPointerAddressSpace();
   BasicBlock *Preheader = CurLoop->getLoopPreheader();
   IRBuilder<> Builder(Preheader->getTerminator());
   SCEVExpander Expander(*SE, *DL, "loop-idiom");
   SCEVExpanderCleaner ExpCleaner(Expander, *DT);
 
   Type *DestInt8PtrTy = Builder.getInt8PtrTy(DestAS);
   Type *IntIdxTy = DL->getIndexType(DestPtr->getType());
 
   bool Changed = false;
   const SCEV *Start = Ev->getStart();
   // Handle negative strided loops.
-  if (NegStride)
+  if (IsNegStride)
     Start = getStartForNegStride(Start, BECount, IntIdxTy, StoreSizeSCEV, SE);
 
   // TODO: ideally we should still be able to generate memset if SCEV expander
   // is taught to generate the dependencies at the latest point.
   if (!isSafeToExpand(Start, *SE))
     return Changed;
 
   // Okay, we have a strided store "p[i]" of a splattable value.  We can turn
bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(
   SCEVExpanderCleaner ExpCleaner(Expander, *DT);
 
   bool Changed = false;
   const SCEV *StrStart = StoreEv->getStart();
   unsigned StrAS = DestPtr->getType()->getPointerAddressSpace();
   Type *IntIdxTy = Builder.getIntNTy(DL->getIndexSizeInBits(StrAS));
 
   APInt Stride = getStoreStride(StoreEv);
-  bool NegStride = StoreSize == -Stride;
+  bool IsNegStride = StoreSize == -Stride;
 
   const SCEV *StoreSizeSCEV = SE->getConstant(BECount->getType(), StoreSize);
   // Handle negative strided loops.
-  if (NegStride)
+  if (IsNegStride)
     StrStart =
         getStartForNegStride(StrStart, BECount, IntIdxTy, StoreSizeSCEV, SE);
 
   // Okay, we have a strided store "p[i]" of a loaded value.  We can turn
   // this into a memcpy in the loop preheader now if we want.  However, this
   // would be unsafe to do if there is anything else in the loop that may read
   // or write the memory region we're storing to.  This includes the load that
   // feeds the stores.  Check for an alias by generating the base address and
if (UseMemMove) {
     }
     Stores.erase(TheLoad);
   }
 
   const SCEV *LdStart = LoadEv->getStart();
   unsigned LdAS = SourcePtr->getType()->getPointerAddressSpace();
 
   // Handle negative strided loops.
-  if (NegStride)
+  if (IsNegStride)
     LdStart =
         getStartForNegStride(LdStart, BECount, IntIdxTy, StoreSizeSCEV, SE);
 
   // For a memcpy, we have to make sure that the input array is not being
   // mutated by the loop.
   Value *LoadBasePtr = Expander.expandCodeFor(
       LdStart, Builder.getInt8PtrTy(LdAS), Preheader->getTerminator());
 
if (UseMemMove) {
     const Value *BP1 = llvm::GetPointerBaseWithConstantOffset(
         LoadBasePtr->stripPointerCasts(), LoadOff, *DL);
     const Value *BP2 = llvm::GetPointerBaseWithConstantOffset(
         StoreBasePtr->stripPointerCasts(), StoreOff, *DL);
     int64_t LoadSize =
         DL->getTypeSizeInBits(TheLoad->getType()).getFixedSize() / 8;
     if (BP1 != BP2 || LoadSize != int64_t(StoreSize))
       return Changed;
-    if ((!NegStride && LoadOff < StoreOff + int64_t(StoreSize)) ||
-        (NegStride && LoadOff + LoadSize > StoreOff))
+    if ((!IsNegStride && LoadOff < StoreOff + int64_t(StoreSize)) ||
+        (IsNegStride && LoadOff + LoadSize > StoreOff))
       return Changed;
   }
 
   if (avoidLIRForMultiBlockLoop())
     return Changed;
 
   // Okay, everything is safe, we can transform this!