[Alignment][NFC] Deprecate VectorUtils::getAlignment

[gchatelet]

Summary

This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

llvm/include/llvm/Analysis/VectorUtils.h

InterleaveGroup(InstTy *Instr, int32_t Stride, Align Alignment)
     assert(Factor > 1 && "Invalid interleave factor");
 
     Reverse = Stride < 0;
     Members[0] = Instr;
   }
 
   bool isReverse() const { return Reverse; }
   uint32_t getFactor() const { return Factor; }
-  uint32_t getAlignment() const { return Alignment.value(); }
+  LLVM_ATTRIBUTE_DEPRECATED(uint32_t getAlignment() const,
+                            "Use getAlign instead.") {
+    return Alignment.value();
+  }
   Align getAlign() const { return Alignment; }
   uint32_t getNumMembers() const { return Members.size(); }
 
   /// Try to insert a new member \p Instr with index \p Index and
   /// alignment \p NewAlign. The index is related to the leader and it could be
   /// negative if it is the new leader.
   ///
   /// \returns false if the instruction doesn't belong to the group.

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

for (unsigned i = 0; i < InterleaveFactor; i++)
         Indices.push_back(i);
   }
 
   // Calculate the cost of the whole interleaved group.
   bool UseMaskForGaps =
       Group->requiresScalarEpilogue() && !isScalarEpilogueAllowed();
   unsigned Cost = TTI.getInterleavedMemoryOpCost(
       I->getOpcode(), WideVecTy, Group->getFactor(), Indices,
-      Group->getAlignment(), AS, Legal->isMaskRequired(I), UseMaskForGaps);
+      Group->getAlign().value(), AS, Legal->isMaskRequired(I), UseMaskForGaps);
 
   if (Group->isReverse()) {
     // TODO: Add support for reversed masked interleaved access.
     assert(!Legal->isMaskRequired(I) &&
            "Reverse masked interleaved access not supported.");
     Cost += Group->getNumMembers() *
             TTI.getShuffleCost(TargetTransformInfo::SK_Reverse, VectorTy, 0);
   }

llvm/lib/Transforms/Vectorize/VPlan.cpp

for (VPRecipeBase &VPI : *VPBB) {
       auto *Inst = cast<Instruction>(VPInst->getUnderlyingValue());
       auto *IG = IAI.getInterleaveGroup(Inst);
       if (!IG)
         continue;
 
       auto NewIGIter = Old2New.find(IG);
       if (NewIGIter == Old2New.end())
         Old2New[IG] = new InterleaveGroup<VPInstruction>(
-            IG->getFactor(), IG->isReverse(), Align(IG->getAlignment()));
+            IG->getFactor(), IG->isReverse(), IG->getAlign());
 
       if (Inst == IG->getInsertPos())
         Old2New[IG]->setInsertPos(VPInst);
 
       InterleaveGroupMap[VPInst] = Old2New[IG];
       InterleaveGroupMap[VPInst]->insertMember(
           VPInst, IG->getIndex(Inst),
           Align(IG->isReverse() ? (-1) * int(IG->getFactor())