[SLP] Don't pass a global CL option as an argument. NFC.

[mcrosier]

Summary

Also fixes an 80-column violation..

Chad

[mssimpso]

LGTM!

include/llvm/Transforms/Vectorize/SLPVectorizer.h

private:
   /// \brief Vectorize the index computations of the getelementptr instructions
   /// collected in GEPs.
   bool vectorizeGEPIndices(BasicBlock *BB, slpvectorizer::BoUpSLP &R);
 
   /// \brief Scan the basic block and look for patterns that are likely to start
   /// a vectorization chain.
   bool vectorizeChainsInBlock(BasicBlock *BB, slpvectorizer::BoUpSLP &R);
 
-  bool vectorizeStoreChain(ArrayRef<Value *> Chain, int CostThreshold,
-                           slpvectorizer::BoUpSLP &R, unsigned VecRegSize);
+  bool vectorizeStoreChain(ArrayRef<Value *> Chain, slpvectorizer::BoUpSLP &R,
+                           unsigned VecRegSize);
 
-  bool vectorizeStores(ArrayRef<StoreInst *> Stores, int costThreshold,
-                       slpvectorizer::BoUpSLP &R);
+  bool vectorizeStores(ArrayRef<StoreInst *> Stores, slpvectorizer::BoUpSLP &R);
 
   /// The store instructions in a basic block organized by base pointer.
   StoreListMap Stores;
 
   /// The getelementptr instructions in a basic block organized by base pointer.
   WeakVHListMap GEPs;
 };
 }
 
 #endif // LLVM_TRANSFORMS_VECTORIZE_SLPVECTORIZER_H

lib/Transforms/Vectorize/SLPVectorizer.cpp

 /// to become invalid. We track when this has happened in the WeakVH array.
 static bool hasValueBeenRAUWed(ArrayRef<Value *> VL, ArrayRef<WeakVH> VH,
                                unsigned SliceBegin, unsigned SliceSize) {
   VL = VL.slice(SliceBegin, SliceSize);
   VH = VH.slice(SliceBegin, SliceSize);
   return !std::equal(VL.begin(), VL.end(), VH.begin());
 }
 
-bool SLPVectorizerPass::vectorizeStoreChain(ArrayRef<Value *> Chain,
-                                            int CostThreshold, BoUpSLP &R,
+bool SLPVectorizerPass::vectorizeStoreChain(ArrayRef<Value *> Chain, BoUpSLP &R,
                                             unsigned VecRegSize) {
   unsigned ChainLen = Chain.size();
   DEBUG(dbgs() << "SLP: Analyzing a store chain of length " << ChainLen
         << "\n");
   unsigned Sz = R.getVectorElementSize(Chain[0]);
   unsigned VF = VecRegSize / Sz;
 
   if (!isPowerOf2_32(Sz) || VF < 2)
for (unsigned i = 0, e = ChainLen; i < e; ++i) {
     if (R.isTreeTinyAndNotFullyVectorizable())
       continue;
 
     R.computeMinimumValueSizes();
 
     int Cost = R.getTreeCost();
 
     DEBUG(dbgs() << "SLP: Found cost=" << Cost << " for VF=" << VF << "\n");
-    if (Cost < CostThreshold) {
+    if (Cost < -SLPCostThreshold) {
       DEBUG(dbgs() << "SLP: Decided to vectorize cost=" << Cost << "\n");
       R.vectorizeTree();
 
       // Move to the next bundle.
       i += VF - 1;
       Changed = true;
     }
   }
 
   return Changed;
 }
 
 bool SLPVectorizerPass::vectorizeStores(ArrayRef<StoreInst *> Stores,
-                                        int costThreshold, BoUpSLP &R) {
+                                        BoUpSLP &R) {
   SetVector<StoreInst *> Heads, Tails;
   SmallDenseMap<StoreInst *, StoreInst *> ConsecutiveChain;
 
   // We may run into multiple chains that merge into a single chain. We mark the
   // stores that we vectorized so that we don't visit the same store twice.
   BoUpSLP::ValueSet VectorizedStores;
   bool Changed = false;
 
while (Tails.count(I) || Heads.count(I)) {
         break;
       Operands.push_back(I);
       // Move to the next value in the chain.
       I = ConsecutiveChain[I];
     }
 
     // FIXME: Is division-by-2 the correct step? Should we assert that the
     // register size is a power-of-2?
-    for (unsigned Size = R.getMaxVecRegSize(); Size >= R.getMinVecRegSize(); Size /= 2) {
-      if (vectorizeStoreChain(Operands, costThreshold, R, Size)) {
+    for (unsigned Size = R.getMaxVecRegSize(); Size >= R.getMinVecRegSize();
+         Size /= 2) {
+      if (vectorizeStoreChain(Operands, R, Size)) {
         // Mark the vectorized stores so that we don't vectorize them again.
         VectorizedStores.insert(Operands.begin(), Operands.end());
         Changed = true;
         break;
       }
     }
   }
 
DEBUG(dbgs() << "SLP: Analyzing a store chain of length "
           << it->second.size() << ".\n");
 
     // Process the stores in chunks of 16.
     // TODO: The limit of 16 inhibits greater vectorization factors.
     //       For example, AVX2 supports v32i8. Increasing this limit, however,
     //       may cause a significant compile-time increase.
     for (unsigned CI = 0, CE = it->second.size(); CI < CE; CI+=16) {
       unsigned Len = std::min<unsigned>(CE - CI, 16);
-      Changed |= vectorizeStores(makeArrayRef(&it->second[CI], Len),
-                                 -SLPCostThreshold, R);
+      Changed |= vectorizeStores(makeArrayRef(&it->second[CI], Len), R);
     }
   }
   return Changed;
 }
 
 char SLPVectorizer::ID = 0;
 static const char lv_name[] = "SLP Vectorizer";
 INITIALIZE_PASS_BEGIN(SLPVectorizer, SV_NAME, lv_name, false, false)