[MemorySSA][NFC] Use const whenever possible

[nikic]

LGTM

llvm/include/llvm/Analysis/MemorySSA.h

public:
   }
 
   BasicBlock *getPhiArgBlock() const { return DefIterator.getPhiArgBlock(); }
 
 private:
   /// Returns true if \p Ptr is guaranteed to be loop invariant for any possible
   /// loop. In particular, this guarantees that it only references a single
   /// MemoryLocation during execution of the containing function.
-  bool IsGuaranteedLoopInvariant(Value *Ptr) const;
+  bool IsGuaranteedLoopInvariant(const Value *Ptr) const;
 
   void fillInCurrentPair() {
     CurrentPair.first = *DefIterator;
     CurrentPair.second = Location;
     if (WalkingPhi && Location.Ptr) {
       // Mark size as unknown, if the location is not guaranteed to be
       // loop-invariant for any possible loop in the function. Setting the size
       // to unknown guarantees that any memory accesses that access locations
       // after the pointer are considered as clobbers, which is important to
       // catch loop carried dependences.
-      if (!IsGuaranteedLoopInvariant(const_cast<Value *>(Location.Ptr)))
+      if (!IsGuaranteedLoopInvariant(Location.Ptr))
         CurrentPair.second =
             Location.getWithNewSize(LocationSize::beforeOrAfterPointer());
       PHITransAddr Translator(
           const_cast<Value *>(Location.Ptr),
           OriginalAccess->getBlock()->getModule()->getDataLayout(), nullptr);
 
       if (!Translator.PHITranslateValue(OriginalAccess->getBlock(),
                                         DefIterator.getPhiArgBlock(), DT,
                                         true)) {
         Value *TransAddr = Translator.getAddr();
         if (TransAddr != Location.Ptr) {
           CurrentPair.second = CurrentPair.second.getWithNewPtr(TransAddr);
 
           if (TransAddr &&
-              !IsGuaranteedLoopInvariant(const_cast<Value *>(TransAddr)))
+              !IsGuaranteedLoopInvariant(TransAddr))
             CurrentPair.second = CurrentPair.second.getWithNewSize(
                 LocationSize::beforeOrAfterPointer());
 
           if (PerformedPhiTranslation)
             *PerformedPhiTranslation = true;
         }
       }
     }

llvm/lib/Analysis/MemorySSA.cpp

 void MemoryDef::deleteMe(DerivedUser *Self) {
   delete static_cast<MemoryDef *>(Self);
 }
 
 void MemoryUse::deleteMe(DerivedUser *Self) {
   delete static_cast<MemoryUse *>(Self);
 }
 
-bool upward_defs_iterator::IsGuaranteedLoopInvariant(Value *Ptr) const {
-  auto IsGuaranteedLoopInvariantBase = [](Value *Ptr) {
+bool upward_defs_iterator::IsGuaranteedLoopInvariant(const Value *Ptr) const {
+  auto IsGuaranteedLoopInvariantBase = [](const Value *Ptr) {
     Ptr = Ptr->stripPointerCasts();
     if (!isa<Instruction>(Ptr))
       return true;
     return isa<AllocaInst>(Ptr);
   };
 
   Ptr = Ptr->stripPointerCasts();
   if (auto *I = dyn_cast<Instruction>(Ptr)) {