[LoopVectorizationLegality] NFC: Mark some interfaces as 'const'

This patch marks blockNeedsPredication, isConsecutivePtr, isMaskRequired
and getSymbolicStrides as 'const'.

include/llvm/Transforms/Vectorize/LoopVectorizationLegality.h

@@ -299,7 +299,7 @@ public:
 
   /// Return true if the block BB needs to be predicated in order for the loop
   /// to be vectorized.
-  bool blockNeedsPredication(BasicBlock *BB);
+  bool blockNeedsPredication(BasicBlock *BB) const;
 
   /// Check if this pointer is consecutive when vectorizing. This happens
   /// when the last index of the GEP is the induction variable, or that the
@@ -311,7 +311,7 @@ public:
   /// -1 - Address is consecutive, and decreasing.
   /// NOTE: This method must only be used before modifying the original scalar
   /// loop. Do not use after invoking 'createVectorizedLoopSkeleton' (PR34965).
-  int isConsecutivePtr(Value *Ptr);
+  int isConsecutivePtr(Value *Ptr) const;
 
   /// Returns true if the value V is uniform within the loop.
   bool isUniform(Value *V);
@@ -350,7 +350,9 @@ public:
 
   /// Returns true if vector representation of the instruction \p I
   /// requires mask.
-  bool isMaskRequired(const Instruction *I) { return MaskedOp.contains(I); }
+  bool isMaskRequired(const Instruction *I) const {
+    return MaskedOp.contains(I);
+  }
 
   unsigned getNumStores() const { return LAI->getNumStores(); }
   unsigned getNumLoads() const { return LAI->getNumLoads(); }
@@ -429,7 +431,7 @@ private:
 
   /// If an access has a symbolic strides, this maps the pointer value to
   /// the stride symbol.
-  const ValueToValueMap *getSymbolicStrides() {
+  const ValueToValueMap *getSymbolicStrides() const {
     // FIXME: Currently, the set of symbolic strides is sometimes queried before
     // it's collected.  This happens from canVectorizeWithIfConvert, when the
     // pointer is checked to reference consecutive elements suitable for a

lib/Transforms/Vectorize/LoopVectorizationLegality.cpp

@@ -376,7 +376,7 @@ static bool hasOutsideLoopUser(const Loop *TheLoop, Instruction *Inst,
   return false;
 }
 
-int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
+int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) const {
   const ValueToValueMap &Strides =
       getSymbolicStrides() ? *getSymbolicStrides() : ValueToValueMap();
 
@@ -879,7 +879,7 @@ bool LoopVectorizationLegality::isFirstOrderRecurrence(const PHINode *Phi) {
   return FirstOrderRecurrences.count(Phi);
 }
 
-bool LoopVectorizationLegality::blockNeedsPredication(BasicBlock *BB) {
+bool LoopVectorizationLegality::blockNeedsPredication(BasicBlock *BB) const {
   return LoopAccessInfo::blockNeedsPredication(BB, TheLoop, DT);
 }