[LAA] Remove one addRuntimeChecks function (NFC).

[fhahn]

Summary

In order to reduce the API surface area (preparation for D78460), remove
a addRuntimeChecks() function and do the additional check in the single
caller.

[Ayal]

Thanks for breaking this up!

llvm/include/llvm/Analysis/LoopAccessAnalysis.h

public:
 
   /// Returns true if the value V is uniform within the loop.
   bool isUniform(Value *V) const;
 
   uint64_t getMaxSafeDepDistBytes() const { return MaxSafeDepDistBytes; }
   unsigned getNumStores() const { return NumStores; }
   unsigned getNumLoads() const { return NumLoads;}
 
-  /// Add code that checks at runtime if the accessed arrays overlap.
-  ///
-  /// Returns a pair of instructions where the first element is the first
-  /// instruction generated in possibly a sequence of instructions and the
-  /// second value is the final comparator value or NULL if no check is needed.
-  std::pair<Instruction *, Instruction *>
-  addRuntimeChecks(Instruction *Loc) const;
-
-  /// Generete the instructions for the checks in \p PointerChecks.
+  /// Add code that checks at runtime if the accessed arrays \in p PointerChecks
+  /// overlap.
   ///
   /// Returns a pair of instructions where the first element is the first
   /// instruction generated in possibly a sequence of instructions and the
   /// second value is the final comparator value or NULL if no check is needed.
   std::pair<Instruction *, Instruction *> addRuntimeChecks(
       Instruction *Loc,
       const SmallVectorImpl<RuntimePointerCheck> &PointerChecks) const;
 

llvm/lib/Analysis/LoopAccessAnalysis.cpp

std::pair<Instruction *, Instruction *> LoopAccessInfo::addRuntimeChecks(
   // the block.
   Instruction *Check = BinaryOperator::CreateAnd(MemoryRuntimeCheck,
                                                  ConstantInt::getTrue(Ctx));
   ChkBuilder.Insert(Check, "memcheck.conflict");
   FirstInst = getFirstInst(FirstInst, Check, Loc);
   return std::make_pair(FirstInst, Check);
 }
 
-std::pair<Instruction *, Instruction *>
-LoopAccessInfo::addRuntimeChecks(Instruction *Loc) const {
-  if (!PtrRtChecking->Need)
-    return std::make_pair(nullptr, nullptr);
-
-  return addRuntimeChecks(Loc, PtrRtChecking->getChecks());
-}
-
 void LoopAccessInfo::collectStridedAccess(Value *MemAccess) {
   Value *Ptr = nullptr;
   if (LoadInst *LI = dyn_cast<LoadInst>(MemAccess))
     Ptr = LI->getPointerOperand();
   else if (StoreInst *SI = dyn_cast<StoreInst>(MemAccess))
     Ptr = SI->getPointerOperand();
   else
     return;

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

void InnerLoopVectorizer::emitMemRuntimeChecks(Loop *L, BasicBlock *Bypass) {
 
   // Reuse existing vector loop preheader for runtime memory checks.
   // Note that new preheader block is generated for vector loop.
   BasicBlock *const MemCheckBlock = L->getLoopPreheader();
 
   // Generate the code that checks in runtime if arrays overlap. We put the
   // checks into a separate block to make the more common case of few elements
   // faster.
+  auto *LAI = Legal->getLAI();
+  const auto &RtPtrChecking = *LAI->getRuntimePointerChecking();
+  if (!RtPtrChecking.Need)
+    return;
   Instruction *FirstCheckInst;
   Instruction *MemRuntimeCheck;
-  std::tie(FirstCheckInst, MemRuntimeCheck) =
-      Legal->getLAI()->addRuntimeChecks(MemCheckBlock->getTerminator());
-  if (!MemRuntimeCheck)
-    return;
+  std::tie(FirstCheckInst, MemRuntimeCheck) = LAI->addRuntimeChecks(
+      MemCheckBlock->getTerminator(), RtPtrChecking.getChecks());
+  assert(MemRuntimeCheck && "Expected runtime checks to be generated");
 
   if (MemCheckBlock->getParent()->hasOptSize()) {
     assert(Cost->Hints->getForce() == LoopVectorizeHints::FK_Enabled &&
            "Cannot emit memory checks when optimizing for size, unless forced "
            "to vectorize.");
     ORE->emit([&]() {
       return OptimizationRemarkAnalysis(DEBUG_TYPE, "VectorizationCodeSize",
                                         L->getStartLoc(), L->getHeader())