[Alignment][NFC] Remove dependency on GlobalObject::setAlignment(unsigned)

[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

[courbet]

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

4764

getValueOr() ? (here and below)

llvm/lib/CodeGen/GlobalMerge.cpp

465

Please avoid repeating Align (here and below).

[gchatelet]

• Address comments, fix ValueTest and Polly

[gchatelet]

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

4764

Unfortunately this doesn't work: MaybeAlign is a llvm::Optional<Align> so getValueOr() only accepts Align values which can't be 0 by definition.
The code will clean itself with the transition of (Alloca|Load|Store)Inst to Align.

llvm/include/llvm/LTO/LTO.h

 
 private:
   Config Conf;
 
   struct RegularLTOState {
     RegularLTOState(unsigned ParallelCodeGenParallelismLevel, Config &Conf);
     struct CommonResolution {
       uint64_t Size = 0;
-      unsigned Align = 0;
+      MaybeAlign Align;
       /// Record if at least one instance of the common was marked as prevailing
       bool Prevailing = false;
     };
     std::map<std::string, CommonResolution> Commons;
 
     unsigned ParallelCodeGenParallelismLevel;
     LTOLLVMContext Ctx;
     std::unique_ptr<Module> CombinedModule;

llvm/lib/AsmParser/LLParser.cpp

if (Function *Fn = dyn_cast<Function>(V)) {
       AttrBuilder FnAttrs(AS.getFnAttributes());
       AS = AS.removeAttributes(Context, AttributeList::FunctionIndex);
 
       FnAttrs.merge(B);
 
       // If the alignment was parsed as an attribute, move to the alignment
       // field.
       if (FnAttrs.hasAlignmentAttr()) {
-        Fn->setAlignment(FnAttrs.getAlignment());
+        Fn->setAlignment(MaybeAlign(FnAttrs.getAlignment()));
         FnAttrs.removeAttribute(Attribute::Alignment);
       }
 
       AS = AS.addAttributes(Context, AttributeList::FunctionIndex,
                             AttributeSet::get(Context, FnAttrs));
       Fn->setAttributes(AS);
     } else if (CallInst *CI = dyn_cast<CallInst>(V)) {
       AttributeList AS = CI->getAttributes();
while (Lex.getKind() == lltok::comma) {
     } else if (Lex.getKind() == lltok::kw_partition) {
       Lex.Lex();
       GV->setPartition(Lex.getStrVal());
       if (ParseToken(lltok::StringConstant, "expected partition string"))
         return true;
     } else if (Lex.getKind() == lltok::kw_align) {
       unsigned Alignment;
       if (ParseOptionalAlignment(Alignment)) return true;
-      GV->setAlignment(Alignment);
+      GV->setAlignment(MaybeAlign(Alignment));
     } else if (Lex.getKind() == lltok::MetadataVar) {
       if (ParseGlobalObjectMetadataAttachment(*GV))
         return true;
     } else {
       Comdat *C;
       if (parseOptionalComdat(Name, C))
         return true;
       if (C)
bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
 
   Fn->setLinkage((GlobalValue::LinkageTypes)Linkage);
   maybeSetDSOLocal(DSOLocal, *Fn);
   Fn->setVisibility((GlobalValue::VisibilityTypes)Visibility);
   Fn->setDLLStorageClass((GlobalValue::DLLStorageClassTypes)DLLStorageClass);
   Fn->setCallingConv(CC);
   Fn->setAttributes(PAL);
   Fn->setUnnamedAddr(UnnamedAddr);
-  Fn->setAlignment(Alignment);
+  Fn->setAlignment(MaybeAlign(Alignment));
   Fn->setSection(Section);
   Fn->setPartition(Partition);
   Fn->setComdat(C);
   Fn->setPersonalityFn(PersonalityFn);
   if (!GC.empty()) Fn->setGC(GC);
   Fn->setPrefixData(Prefix);
   Fn->setPrologueData(Prologue);
   ForwardRefAttrGroups[Fn] = FwdRefAttrGrps;

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

private:
 
   /// Upgrades old-style typeless byval attributes by adding the corresponding
   /// argument's pointee type.
   void propagateByValTypes(CallBase *CB, ArrayRef<Type *> ArgsFullTys);
 
   /// Converts alignment exponent (i.e. power of two (or zero)) to the
   /// corresponding alignment to use. If alignment is too large, returns
   /// a corresponding error code.
-  Error parseAlignmentValue(uint64_t Exponent, unsigned &Alignment);
+  Error parseAlignmentValue(uint64_t Exponent, MaybeAlign &Alignment);
   Error parseAttrKind(uint64_t Code, Attribute::AttrKind *Kind);
   Error parseModule(uint64_t ResumeBit, bool ShouldLazyLoadMetadata = false);
 
   Error parseComdatRecord(ArrayRef<uint64_t> Record);
   Error parseGlobalVarRecord(ArrayRef<uint64_t> Record);
   Error parseFunctionRecord(ArrayRef<uint64_t> Record);
   Error parseGlobalIndirectSymbolRecord(unsigned BitCode,
                                         ArrayRef<uint64_t> Record);
static Attribute::AttrKind getAttrFromCode(uint64_t Code) {
   case bitc::ATTR_KIND_IMMARG:
     return Attribute::ImmArg;
   case bitc::ATTR_KIND_SANITIZE_MEMTAG:
     return Attribute::SanitizeMemTag;
   }
 }
 
 Error BitcodeReader::parseAlignmentValue(uint64_t Exponent,
-                                         unsigned &Alignment) {
+                                         MaybeAlign &Alignment) {
   // Note: Alignment in bitcode files is incremented by 1, so that zero
   // can be used for default alignment.
   if (Exponent > Value::MaxAlignmentExponent + 1)
     return error("Invalid alignment value");
-  Alignment = (1 << static_cast<unsigned>(Exponent)) >> 1;
+  Alignment = decodeMaybeAlign(Exponent);
   return Error::success();
 }
 
 Error BitcodeReader::parseAttrKind(uint64_t Code, Attribute::AttrKind *Kind) {
   *Kind = getAttrFromCode(Code);
   if (*Kind == Attribute::None)
     return error("Unknown attribute kind (" + Twine(Code) + ")");
   return Error::success();
if (explicitType) {
     if (!Ty->isPointerTy())
       return error("Invalid type for value");
     AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
     std::tie(FullTy, Ty) = getPointerElementTypes(FullTy);
   }
 
   uint64_t RawLinkage = Record[3];
   GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
-  unsigned Alignment;
+  MaybeAlign Alignment;
   if (Error Err = parseAlignmentValue(Record[4], Alignment))
     return Err;
   std::string Section;
   if (Record[5]) {
     if (Record[5] - 1 >= SectionTable.size())
       return error("Invalid ID");
     Section = SectionTable[Record[5] - 1];
   }
if (!Func->hasParamAttribute(i, Attribute::ByVal))
       continue;
 
     Type *PTy = cast<FunctionType>(FullFTy)->getParamType(i);
     Func->removeParamAttr(i, Attribute::ByVal);
     Func->addParamAttr(i, Attribute::getWithByValType(
                               Context, getPointerElementFlatType(PTy)));
   }
 
-  unsigned Alignment;
+  MaybeAlign Alignment;
   if (Error Err = parseAlignmentValue(Record[5], Alignment))
     return Err;
   Func->setAlignment(Alignment);
   if (Record[6]) {
     if (Record[6] - 1 >= SectionTable.size())
       return error("Invalid ID");
     Func->setSection(SectionTable[Record[6] - 1]);
   }
case bitc::FUNC_CODE_INST_ALLOCA: { // ALLOCA: [instty, opty, op, align]
       if ((AlignRecord & ExplicitTypeMask) == 0) {
         auto *PTy = dyn_cast_or_null<PointerType>(Ty);
         if (!PTy)
           return error("Old-style alloca with a non-pointer type");
         std::tie(FullTy, Ty) = getPointerElementTypes(FullTy);
       }
       Type *OpTy = getTypeByID(Record[1]);
       Value *Size = getFnValueByID(Record[2], OpTy);
-      unsigned Align;
+      MaybeAlign Align;
       if (Error Err = parseAlignmentValue(AlignRecord & ~FlagMask, Align)) {
         return Err;
       }
       if (!Ty || !Size)
         return error("Invalid record");
 
       // FIXME: Make this an optional field.
       const DataLayout &DL = TheModule->getDataLayout();
       unsigned AS = DL.getAllocaAddrSpace();
 
-      AllocaInst *AI = new AllocaInst(Ty, AS, Size, Align);
+      AllocaInst *AI = new AllocaInst(Ty, AS, Size, Align ? Align->value() : 0);
       AI->setUsedWithInAlloca(InAlloca);
       AI->setSwiftError(SwiftError);
       I = AI;
       FullTy = PointerType::get(FullTy, AS);
       InstructionList.push_back(I);
       break;
     }
     case bitc::FUNC_CODE_INST_LOAD: { // LOAD: [opty, op, align, vol]
case bitc::FUNC_CODE_INST_LOAD: { // LOAD: [opty, op, align, vol]
         FullTy = getFullyStructuredTypeByID(Record[OpNum++]);
         Ty = flattenPointerTypes(FullTy);
       } else
         std::tie(FullTy, Ty) = getPointerElementTypes(FullTy);
 
       if (Error Err = typeCheckLoadStoreInst(Ty, Op->getType()))
         return Err;
 
-      unsigned Align;
+      MaybeAlign Align;
       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
         return Err;
-      I = new LoadInst(Ty, Op, "", Record[OpNum + 1], Align);
+      I = new LoadInst(Ty, Op, "", Record[OpNum + 1],
+                       Align ? Align->value() : 0);
       InstructionList.push_back(I);
       break;
     }
     case bitc::FUNC_CODE_INST_LOADATOMIC: {
        // LOADATOMIC: [opty, op, align, vol, ordering, ssid]
       unsigned OpNum = 0;
       Value *Op;
       if (getValueTypePair(Record, OpNum, NextValueNo, Op, &FullTy) ||
case bitc::FUNC_CODE_INST_LOADATOMIC: {
       if (Ordering == AtomicOrdering::NotAtomic ||
           Ordering == AtomicOrdering::Release ||
           Ordering == AtomicOrdering::AcquireRelease)
         return error("Invalid record");
       if (Ordering != AtomicOrdering::NotAtomic && Record[OpNum] == 0)
         return error("Invalid record");
       SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 3]);
 
-      unsigned Align;
+      MaybeAlign Align;
       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
         return Err;
-      I = new LoadInst(Ty, Op, "", Record[OpNum + 1], Align, Ordering, SSID);
+      I = new LoadInst(Ty, Op, "", Record[OpNum + 1],
+                       Align ? Align->value() : 0, Ordering, SSID);
       InstructionList.push_back(I);
       break;
     }
     case bitc::FUNC_CODE_INST_STORE:
     case bitc::FUNC_CODE_INST_STORE_OLD: { // STORE2:[ptrty, ptr, val, align, vol]
       unsigned OpNum = 0;
       Value *Val, *Ptr;
       Type *FullTy;
       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr, &FullTy) ||
           (BitCode == bitc::FUNC_CODE_INST_STORE
                ? getValueTypePair(Record, OpNum, NextValueNo, Val)
                : popValue(Record, OpNum, NextValueNo,
                           getPointerElementFlatType(FullTy), Val)) ||
           OpNum + 2 != Record.size())
         return error("Invalid record");
 
       if (Error Err = typeCheckLoadStoreInst(Val->getType(), Ptr->getType()))
         return Err;
-      unsigned Align;
+      MaybeAlign Align;
       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
         return Err;
-      I = new StoreInst(Val, Ptr, Record[OpNum+1], Align);
+      I = new StoreInst(Val, Ptr, Record[OpNum + 1],
+                        Align ? Align->value() : 0);
       InstructionList.push_back(I);
       break;
     }
     case bitc::FUNC_CODE_INST_STOREATOMIC:
     case bitc::FUNC_CODE_INST_STOREATOMIC_OLD: {
       // STOREATOMIC: [ptrty, ptr, val, align, vol, ordering, ssid]
       unsigned OpNum = 0;
       Value *Val, *Ptr;
case bitc::FUNC_CODE_INST_STOREATOMIC_OLD: {
       if (Ordering == AtomicOrdering::NotAtomic ||
           Ordering == AtomicOrdering::Acquire ||
           Ordering == AtomicOrdering::AcquireRelease)
         return error("Invalid record");
       SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 3]);
       if (Ordering != AtomicOrdering::NotAtomic && Record[OpNum] == 0)
         return error("Invalid record");
 
-      unsigned Align;
+      MaybeAlign Align;
       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
         return Err;
-      I = new StoreInst(Val, Ptr, Record[OpNum+1], Align, Ordering, SSID);
+      I = new StoreInst(Val, Ptr, Record[OpNum + 1], Align ? Align->value() : 0,
+                        Ordering, SSID);
       InstructionList.push_back(I);
       break;
     }
     case bitc::FUNC_CODE_INST_CMPXCHG_OLD:
     case bitc::FUNC_CODE_INST_CMPXCHG: {
       // CMPXCHG:[ptrty, ptr, cmp, new, vol, successordering, ssid,
       //          failureordering?, isweak?]
       unsigned OpNum = 0;

llvm/lib/CodeGen/CodeGenPrepare.cpp

for (auto &Arg : CI->arg_operands()) {
       // object (i.e. they are uniquely initialized in this object), and
       // over-aligning global variables that have an explicit section is
       // forbidden.
       GlobalVariable *GV;
       if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->canIncreaseAlignment() &&
           GV->getPointerAlignment(*DL) < PrefAlign &&
           DL->getTypeAllocSize(GV->getValueType()) >=
               MinSize + Offset2)
-        GV->setAlignment(PrefAlign);
+        GV->setAlignment(MaybeAlign(PrefAlign));
     }
     // If this is a memcpy (or similar) then we may be able to improve the
     // alignment
     if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(CI)) {
       unsigned DestAlign = getKnownAlignment(MI->getDest(), *DL);
       if (DestAlign > MI->getDestAlignment())
         MI->setDestAlignment(DestAlign);
       if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {

llvm/lib/CodeGen/GlobalMerge.cpp

while (i != -1) {
     ssize_t j = 0;
     uint64_t MergedSize = 0;
     std::vector<Type*> Tys;
     std::vector<Constant*> Inits;
     std::vector<unsigned> StructIdxs;
 
     bool HasExternal = false;
     StringRef FirstExternalName;
-    unsigned MaxAlign = 1;
+    Align MaxAlign;
     unsigned CurIdx = 0;
     for (j = i; j != -1; j = GlobalSet.find_next(j)) {
       Type *Ty = Globals[j]->getValueType();
 
       // Make sure we use the same alignment AsmPrinter would use.
-      unsigned Align = DL.getPreferredAlignment(Globals[j]);
-      unsigned Padding = alignTo(MergedSize, Align) - MergedSize;
+      Align Alignment = Align(DL.getPreferredAlignment(Globals[j]));
+      unsigned Padding = alignTo(MergedSize, Alignment) - MergedSize;
       MergedSize += Padding;
       MergedSize += DL.getTypeAllocSize(Ty);
       if (MergedSize > MaxOffset) {
         break;
       }
       if (Padding) {
         Tys.push_back(ArrayType::get(Int8Ty, Padding));
         Inits.push_back(ConstantAggregateZero::get(Tys.back()));
         ++CurIdx;
       }
       Tys.push_back(Ty);
       Inits.push_back(Globals[j]->getInitializer());
       StructIdxs.push_back(CurIdx++);
 
-      MaxAlign = std::max(MaxAlign, Align);
+      MaxAlign = std::max(MaxAlign, Alignment);
 
       if (Globals[j]->hasExternalLinkage() && !HasExternal) {
         HasExternal = true;
         FirstExternalName = Globals[j]->getName();
       }
     }
 
     // Exit early if there is only one global to merge.

llvm/lib/CodeGen/LowerEmuTLS.cpp

bool LowerEmuTLS::addEmuTlsVar(Module &M, const GlobalVariable *GV) {
   GlobalVariable *EmuTlsTmplVar = nullptr;
   if (InitValue) {
     std::string EmuTlsTmplName = ("__emutls_t." + GV->getName()).str();
     EmuTlsTmplVar = dyn_cast_or_null<GlobalVariable>(
         M.getOrInsertGlobal(EmuTlsTmplName, GVType));
     assert(EmuTlsTmplVar && "Failed to create emualted TLS initializer");
     EmuTlsTmplVar->setConstant(true);
     EmuTlsTmplVar->setInitializer(const_cast<Constant*>(InitValue));
-    EmuTlsTmplVar->setAlignment(GVAlignment);
+    EmuTlsTmplVar->setAlignment(Align(GVAlignment));
     copyLinkageVisibility(M, GV, EmuTlsTmplVar);
   }
 
   // Define "__emutls_v.*" with initializer and alignment.
   Constant *ElementValues[4] = {
       ConstantInt::get(WordType, DL.getTypeStoreSize(GVType)),
       ConstantInt::get(WordType, GVAlignment),
       NullPtr, EmuTlsTmplVar ? EmuTlsTmplVar : NullPtr
   };
   ArrayRef<Constant*> ElementValueArray(ElementValues, 4);
   EmuTlsVar->setInitializer(
       ConstantStruct::get(EmuTlsVarType, ElementValueArray));
-  unsigned MaxAlignment = std::max(
-      DL.getABITypeAlignment(WordType),
-      DL.getABITypeAlignment(VoidPtrType));
+  Align MaxAlignment = Align(std::max(DL.getABITypeAlignment(WordType),
+                                      DL.getABITypeAlignment(VoidPtrType)));
   EmuTlsVar->setAlignment(MaxAlignment);
   return true;
 }

llvm/lib/ExecutionEngine/Orc/Speculation.cpp

for (auto &Fn : M.getFunctionList()) {
         if (IRNames.hasValue()) {
 
           // Emit globals for each function.
           auto LoadValueTy = Type::getInt8Ty(MContext);
           auto SpeculatorGuard = new GlobalVariable(
               M, LoadValueTy, false, GlobalValue::LinkageTypes::InternalLinkage,
               ConstantInt::get(LoadValueTy, 0),
               "__orc_speculate.guard.for." + Fn.getName());
-          SpeculatorGuard->setAlignment(1);
+          SpeculatorGuard->setAlignment(Align::None());
           SpeculatorGuard->setUnnamedAddr(GlobalValue::UnnamedAddr::Local);
 
           BasicBlock &ProgramEntry = Fn.getEntryBlock();
           // Create BasicBlocks before the program's entry basicblock
           BasicBlock *SpeculateBlock = BasicBlock::Create(
               MContext, "__orc_speculate.block", &Fn, &ProgramEntry);
           BasicBlock *SpeculateDecisionBlock = BasicBlock::Create(
               MContext, "__orc_speculate.decision.block", &Fn, SpeculateBlock);

llvm/lib/IR/Core.cpp

unsigned LLVMGetAlignment(LLVMValueRef V) {
 
   llvm_unreachable(
       "only GlobalValue, AllocaInst, LoadInst and StoreInst have alignment");
 }
 
 void LLVMSetAlignment(LLVMValueRef V, unsigned Bytes) {
   Value *P = unwrap<Value>(V);
   if (GlobalObject *GV = dyn_cast<GlobalObject>(P))
-    GV->setAlignment(Bytes);
+    GV->setAlignment(MaybeAlign(Bytes));
   else if (AllocaInst *AI = dyn_cast<AllocaInst>(P))
     AI->setAlignment(MaybeAlign(Bytes));
   else if (LoadInst *LI = dyn_cast<LoadInst>(P))
     LI->setAlignment(MaybeAlign(Bytes));
   else if (StoreInst *SI = dyn_cast<StoreInst>(P))
     SI->setAlignment(MaybeAlign(Bytes));
   else
     llvm_unreachable(

llvm/lib/IR/Globals.cpp

void GlobalObject::setAlignment(MaybeAlign Align) {
   unsigned OldData = getGlobalValueSubClassData();
   setGlobalValueSubClassData((OldData & ~AlignmentMask) | AlignmentData);
   assert(MaybeAlign(getAlignment()) == Align &&
          "Alignment representation error!");
 }
 
 void GlobalObject::copyAttributesFrom(const GlobalObject *Src) {
   GlobalValue::copyAttributesFrom(Src);
-  setAlignment(Src->getAlignment());
+  setAlignment(MaybeAlign(Src->getAlignment()));
   setSection(Src->getSection());
 }
 
 std::string GlobalValue::getGlobalIdentifier(StringRef Name,
                                              GlobalValue::LinkageTypes Linkage,
                                              StringRef FileName) {
 
   // Value names may be prefixed with a binary '1' to indicate

llvm/lib/IR/IRBuilder.cpp

GlobalVariable *IRBuilderBase::CreateGlobalString(StringRef Str,
                                                   unsigned AddressSpace) {
   Constant *StrConstant = ConstantDataArray::getString(Context, Str);
   Module &M = *BB->getParent()->getParent();
   auto *GV = new GlobalVariable(M, StrConstant->getType(), true,
                                 GlobalValue::PrivateLinkage, StrConstant, Name,
                                 nullptr, GlobalVariable::NotThreadLocal,
                                 AddressSpace);
   GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
-  GV->setAlignment(1);
+  GV->setAlignment(Align::None());
   return GV;
 }
 
 Type *IRBuilderBase::getCurrentFunctionReturnType() const {
   assert(BB && BB->getParent() && "No current function!");
   return BB->getParent()->getReturnType();
 }
 

llvm/lib/LTO/LTO.cpp

for (const InputFile::Symbol &Sym : Syms) {
     // Common resolution: collect the maximum size/alignment over all commons.
     // We also record if we see an instance of a common as prevailing, so that
     // if none is prevailing we can ignore it later.
     if (Sym.isCommon()) {
       // FIXME: We should figure out what to do about commons defined by asm.
       // For now they aren't reported correctly by ModuleSymbolTable.
       auto &CommonRes = RegularLTO.Commons[Sym.getIRName()];
       CommonRes.Size = std::max(CommonRes.Size, Sym.getCommonSize());
-      CommonRes.Align = std::max(CommonRes.Align, Sym.getCommonAlignment());
+      CommonRes.Align =
+          std::max(CommonRes.Align, MaybeAlign(Sym.getCommonAlignment()));
       CommonRes.Prevailing |= Res.Prevailing;
     }
 
   }
   if (!M.getComdatSymbolTable().empty())
     for (GlobalValue &GV : M.global_values())
       handleNonPrevailingComdat(GV, NonPrevailingComdats);
   assert(MsymI == MsymE);

llvm/lib/Linker/IRMover.cpp

GlobalVariable *IRLinker::copyGlobalVariableProto(const GlobalVariable *SGVar) {
   // identical version of the symbol over in the dest module... the
   // initializer will be filled in later by LinkGlobalInits.
   GlobalVariable *NewDGV =
       new GlobalVariable(DstM, TypeMap.get(SGVar->getValueType()),
                          SGVar->isConstant(), GlobalValue::ExternalLinkage,
                          /*init*/ nullptr, SGVar->getName(),
                          /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(),
                          SGVar->getType()->getAddressSpace());
-  NewDGV->setAlignment(SGVar->getAlignment());
+  NewDGV->setAlignment(MaybeAlign(SGVar->getAlignment()));
   NewDGV->copyAttributesFrom(SGVar);
   return NewDGV;
 }
 
 AttributeList IRLinker::mapAttributeTypes(LLVMContext &C, AttributeList Attrs) {
   for (unsigned i = 0; i < Attrs.getNumAttrSets(); ++i) {
     if (Attrs.hasAttribute(i, Attribute::ByVal)) {
       Type *Ty = Attrs.getAttribute(i, Attribute::ByVal).getValueAsType();

llvm/lib/Linker/LinkModules.cpp

if (DGV && !GV.hasLocalLinkage() && !GV.hasAppendingLinkage()) {
     auto *SGVar = dyn_cast<GlobalVariable>(&GV);
     if (DGVar && SGVar) {
       if (DGVar->isDeclaration() && SGVar->isDeclaration() &&
           (!DGVar->isConstant() || !SGVar->isConstant())) {
         DGVar->setConstant(false);
         SGVar->setConstant(false);
       }
       if (DGVar->hasCommonLinkage() && SGVar->hasCommonLinkage()) {
-        unsigned Align = std::max(DGVar->getAlignment(), SGVar->getAlignment());
+        MaybeAlign Align =
+            MaybeAlign(std::max(DGVar->getAlignment(), SGVar->getAlignment()));
         SGVar->setAlignment(Align);
         DGVar->setAlignment(Align);
       }
     }
 
     GlobalValue::VisibilityTypes Visibility =
         getMinVisibility(DGV->getVisibility(), GV.getVisibility());
     DGV->setVisibility(Visibility);

llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp

bool AMDGPUPromoteAlloca::handleAlloca(AllocaInst &I, bool SufficientLDS) {
   GlobalVariable *GV = new GlobalVariable(
       *Mod, GVTy, false, GlobalValue::InternalLinkage,
       UndefValue::get(GVTy),
       Twine(F->getName()) + Twine('.') + I.getName(),
       nullptr,
       GlobalVariable::NotThreadLocal,
       AMDGPUAS::LOCAL_ADDRESS);
   GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
-  GV->setAlignment(I.getAlignment());
+  GV->setAlignment(MaybeAlign(I.getAlignment()));
 
   Value *TCntY, *TCntZ;
 
   std::tie(TCntY, TCntZ) = getLocalSizeYZ(Builder);
   Value *TIdX = getWorkitemID(Builder, 0);
   Value *TIdY = getWorkitemID(Builder, 1);
   Value *TIdZ = getWorkitemID(Builder, 2);
 

llvm/lib/Transforms/IPO/ConstantMerge.cpp

 static void replace(Module &M, GlobalVariable *Old, GlobalVariable *New) {
   Constant *NewConstant = New;
 
   LLVM_DEBUG(dbgs() << "Replacing global: @" << Old->getName() << " -> @"
                     << New->getName() << "\n");
 
   // Bump the alignment if necessary.
   if (Old->getAlignment() || New->getAlignment())
-    New->setAlignment(std::max(getAlignment(Old), getAlignment(New)));
+    New->setAlignment(Align(std::max(getAlignment(Old), getAlignment(New))));
 
   copyDebugLocMetadata(Old, New);
   Old->replaceAllUsesWith(NewConstant);
 
   // Delete the global value from the module.
   assert(Old->hasLocalLinkage() &&
          "Refusing to delete an externally visible global variable.");
   Old->eraseFromParent();

llvm/lib/Transforms/IPO/CrossDSOCFI.cpp

void CrossDSOCFI::buildCFICheck(Module &M) {
   LLVMContext &Ctx = M.getContext();
   FunctionCallee C = M.getOrInsertFunction(
       "__cfi_check", Type::getVoidTy(Ctx), Type::getInt64Ty(Ctx),
       Type::getInt8PtrTy(Ctx), Type::getInt8PtrTy(Ctx));
   Function *F = dyn_cast<Function>(C.getCallee());
   // Take over the existing function. The frontend emits a weak stub so that the
   // linker knows about the symbol; this pass replaces the function body.
   F->deleteBody();
-  F->setAlignment(4096);
+  F->setAlignment(Align(4096));
 
   Triple T(M.getTargetTriple());
   if (T.isARM() || T.isThumb())
     F->addFnAttr("target-features", "+thumb-mode");
 
   auto args = F->arg_begin();
   Value &CallSiteTypeId = *(args++);
   CallSiteTypeId.setName("CallSiteTypeId");

llvm/lib/Transforms/IPO/GlobalOpt.cpp

for (unsigned i = 0, e = NumElements; i != e; ++i) {
       NGV->copyAttributesFrom(GV);
       Globals.push_back(NGV);
       NewGlobals.push_back(NGV);
 
       // Calculate the known alignment of the field.  If the original aggregate
       // had 256 byte alignment for example, something might depend on that:
       // propagate info to each field.
       uint64_t FieldOffset = Layout.getElementOffset(i);
-      unsigned NewAlign = (unsigned)MinAlign(StartAlignment, FieldOffset);
-      if (NewAlign > DL.getABITypeAlignment(STy->getElementType(i)))
+      Align NewAlign = Align(MinAlign(StartAlignment, FieldOffset));
+      if (NewAlign > Align(DL.getABITypeAlignment(STy->getElementType(i))))
         NGV->setAlignment(NewAlign);
 
       // Copy over the debug info for the variable.
       uint64_t Size = DL.getTypeAllocSizeInBits(NGV->getValueType());
       uint64_t FragmentOffsetInBits = Layout.getElementOffsetInBits(i);
       transferSRADebugInfo(GV, NGV, FragmentOffsetInBits, Size, NumElements);
     }
   } else if (SequentialType *STy = dyn_cast<SequentialType>(Ty)) {
     unsigned NumElements = STy->getNumElements();
     if (NumElements > 16 && GV->hasNUsesOrMore(16))
       return nullptr; // It's not worth it.
     NewGlobals.reserve(NumElements);
     auto ElTy = STy->getElementType();
     uint64_t EltSize = DL.getTypeAllocSize(ElTy);
-    unsigned EltAlign = DL.getABITypeAlignment(ElTy);
+    Align EltAlign = Align(DL.getABITypeAlignment(ElTy));
     uint64_t FragmentSizeInBits = DL.getTypeAllocSizeInBits(ElTy);
     for (unsigned i = 0, e = NumElements; i != e; ++i) {
       Constant *In = Init->getAggregateElement(i);
       assert(In && "Couldn't get element of initializer?");
 
       GlobalVariable *NGV = new GlobalVariable(STy->getElementType(), false,
                                                GlobalVariable::InternalLinkage,
                                                In, GV->getName()+"."+Twine(i),
                                                GV->getThreadLocalMode(),
                                               GV->getType()->getAddressSpace());
       NGV->setExternallyInitialized(GV->isExternallyInitialized());
       NGV->copyAttributesFrom(GV);
       Globals.push_back(NGV);
       NewGlobals.push_back(NGV);
 
       // Calculate the known alignment of the field.  If the original aggregate
       // had 256 byte alignment for example, something might depend on that:
       // propagate info to each field.
-      unsigned NewAlign = (unsigned)MinAlign(StartAlignment, EltSize*i);
+      Align NewAlign = Align(MinAlign(StartAlignment, EltSize * i));
       if (NewAlign > EltAlign)
         NGV->setAlignment(NewAlign);
       transferSRADebugInfo(GV, NGV, FragmentSizeInBits * i, FragmentSizeInBits,
                            NumElements);
     }
   }
 
   if (NewGlobals.empty())

llvm/lib/Transforms/IPO/LowerTypeTests.cpp

void LowerTypeTestsModule::buildBitSetsFromGlobalVariables(
   // Build a new global with the combined contents of the referenced globals.
   // This global is a struct whose even-indexed elements contain the original
   // contents of the referenced globals and whose odd-indexed elements contain
   // any padding required to align the next element to the next power of 2 plus
   // any additional padding required to meet its alignment requirements.
   std::vector<Constant *> GlobalInits;
   const DataLayout &DL = M.getDataLayout();
   DenseMap<GlobalTypeMember *, uint64_t> GlobalLayout;
-  uint64_t MaxAlign = 0;
+  Align MaxAlign;
   uint64_t CurOffset = 0;
   uint64_t DesiredPadding = 0;
   for (GlobalTypeMember *G : Globals) {
     auto *GV = cast<GlobalVariable>(G->getGlobal());
-    uint64_t Align = GV->getAlignment();
-    if (Align == 0)
-      Align = DL.getABITypeAlignment(GV->getValueType());
-    MaxAlign = std::max(MaxAlign, Align);
-    uint64_t GVOffset = alignTo(CurOffset + DesiredPadding, Align);
+    MaybeAlign Alignment = MaybeAlign(GV->getAlignment());
+    if (!Alignment)
+      Alignment = Align(DL.getABITypeAlignment(GV->getValueType()));
+    MaxAlign = std::max(MaxAlign, *Alignment);
+    uint64_t GVOffset = alignTo(CurOffset + DesiredPadding, *Alignment);
     GlobalLayout[G] = GVOffset;
     if (GVOffset != 0) {
       uint64_t Padding = GVOffset - CurOffset;
       GlobalInits.push_back(
           ConstantAggregateZero::get(ArrayType::get(Int8Ty, Padding)));
     }
 
     GlobalInits.push_back(GV->getInitializer());
void LowerTypeTestsModule::createJumpTable(
 
   Triple::ArchType JumpTableArch = selectJumpTableArmEncoding(Functions, Arch);
 
   for (unsigned I = 0; I != Functions.size(); ++I)
     createJumpTableEntry(AsmOS, ConstraintOS, JumpTableArch, AsmArgs,
                          cast<Function>(Functions[I]->getGlobal()));
 
   // Align the whole table by entry size.
-  F->setAlignment(getJumpTableEntrySize());
+  F->setAlignment(Align(getJumpTableEntrySize()));
   // Skip prologue.
   // Disabled on win32 due to https://llvm.org/bugs/show_bug.cgi?id=28641#c3.
   // Luckily, this function does not get any prologue even without the
   // attribute.
   if (OS != Triple::Win32)
     F->addFnAttr(Attribute::Naked);
   if (JumpTableArch == Triple::arm)
     F->addFnAttr("target-features", "-thumb-mode");

llvm/lib/Transforms/IPO/MergeFunctions.cpp

 // Replace G with an alias to F (deleting function G)
 void MergeFunctions::writeAlias(Function *F, Function *G) {
   Constant *BitcastF = ConstantExpr::getBitCast(F, G->getType());
   PointerType *PtrType = G->getType();
   auto *GA = GlobalAlias::create(
       PtrType->getElementType(), PtrType->getAddressSpace(),
       G->getLinkage(), "", BitcastF, G->getParent());
 
-  F->setAlignment(std::max(F->getAlignment(), G->getAlignment()));
+  F->setAlignment(MaybeAlign(std::max(F->getAlignment(), G->getAlignment())));
   GA->takeName(G);
   GA->setVisibility(G->getVisibility());
   GA->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
 
   removeUsers(G);
   G->replaceAllUsesWith(GA);
   G->eraseFromParent();
 
if (F->isInterposable()) {
     // Make them both thunks to the same internal function.
     Function *NewF = Function::Create(F->getFunctionType(), F->getLinkage(),
                                       F->getAddressSpace(), "", F->getParent());
     NewF->copyAttributesFrom(F);
     NewF->takeName(F);
     removeUsers(F);
     F->replaceAllUsesWith(NewF);
 
-    unsigned MaxAlignment = std::max(G->getAlignment(), NewF->getAlignment());
+    MaybeAlign MaxAlignment =
+        MaybeAlign(std::max(G->getAlignment(), NewF->getAlignment()));
 
     writeThunkOrAlias(F, G);
     writeThunkOrAlias(F, NewF);
 
     F->setAlignment(MaxAlignment);
     F->setLinkage(GlobalValue::PrivateLinkage);
     ++NumDoubleWeak;
     ++NumFunctionsMerged;

llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp

 }
 
 void DevirtModule::rebuildGlobal(VTableBits &B) {
   if (B.Before.Bytes.empty() && B.After.Bytes.empty())
     return;
 
   // Align the before byte array to the global's minimum alignment so that we
   // don't break any alignment requirements on the global.
-  unsigned Align = B.GV->getAlignment();
-  if (Align == 0)
-    Align = M.getDataLayout().getABITypeAlignment(B.GV->getValueType());
-  B.Before.Bytes.resize(alignTo(B.Before.Bytes.size(), Align));
+  MaybeAlign Alignment = MaybeAlign(B.GV->getAlignment());
+  if (!Alignment)
+    Alignment =
+        Align(M.getDataLayout().getABITypeAlignment(B.GV->getValueType()));
+  B.Before.Bytes.resize(alignTo(B.Before.Bytes.size(), Alignment));
 
   // Before was stored in reverse order; flip it now.
   for (size_t I = 0, Size = B.Before.Bytes.size(); I != Size / 2; ++I)
     std::swap(B.Before.Bytes[I], B.Before.Bytes[Size - 1 - I]);
 
   // Build an anonymous global containing the before bytes, followed by the
   // original initializer, followed by the after bytes.
   auto NewInit = ConstantStruct::getAnon(
       {ConstantDataArray::get(M.getContext(), B.Before.Bytes),
        B.GV->getInitializer(),
        ConstantDataArray::get(M.getContext(), B.After.Bytes)});
   auto NewGV =
       new GlobalVariable(M, NewInit->getType(), B.GV->isConstant(),
                          GlobalVariable::PrivateLinkage, NewInit, "", B.GV);
   NewGV->setSection(B.GV->getSection());
   NewGV->setComdat(B.GV->getComdat());
-  NewGV->setAlignment(B.GV->getAlignment());
+  NewGV->setAlignment(MaybeAlign(B.GV->getAlignment()));
 
   // Copy the original vtable's metadata to the anonymous global, adjusting
   // offsets as required.
   NewGV->copyMetadata(B.GV, B.Before.Bytes.size());
 
   // Build an alias named after the original global, pointing at the second
   // element (the original initializer).
   auto Alias = GlobalAlias::create(

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

GlobalVariable *Metadata =
         CreateMetadataGlobal(M, Initializer, G->getName());
 
     // The MSVC linker always inserts padding when linking incrementally. We
     // cope with that by aligning each struct to its size, which must be a power
     // of two.
     unsigned SizeOfGlobalStruct = DL.getTypeAllocSize(Initializer->getType());
     assert(isPowerOf2_32(SizeOfGlobalStruct) &&
            "global metadata will not be padded appropriately");
-    Metadata->setAlignment(SizeOfGlobalStruct);
+    Metadata->setAlignment(assumeAligned(SizeOfGlobalStruct));
 
     SetComdatForGlobalMetadata(G, Metadata, "");
   }
 }
 
 void ModuleAddressSanitizer::InstrumentGlobalsELF(
     IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
     ArrayRef<Constant *> MetadataInitializers,
void ModuleAddressSanitizer::InstrumentGlobalsWithMetadataArray(
   // On platforms that don't have a custom metadata section, we emit an array
   // of global metadata structures.
   ArrayType *ArrayOfGlobalStructTy =
       ArrayType::get(MetadataInitializers[0]->getType(), N);
   auto AllGlobals = new GlobalVariable(
       M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
       ConstantArray::get(ArrayOfGlobalStructTy, MetadataInitializers), "");
   if (Mapping.Scale > 3)
-    AllGlobals->setAlignment(1ULL << Mapping.Scale);
+    AllGlobals->setAlignment(Align(1ULL << Mapping.Scale));
 
   IRB.CreateCall(AsanRegisterGlobals,
                  {IRB.CreatePointerCast(AllGlobals, IntptrTy),
                   ConstantInt::get(IntptrTy, N)});
 
   // We also need to unregister globals at the end, e.g., when a shared library
   // gets closed.
   IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
for (size_t i = 0; i < n; i++) {
     GlobalValue::LinkageTypes Linkage = G->getLinkage();
     if (G->isConstant() && Linkage == GlobalValue::PrivateLinkage)
       Linkage = GlobalValue::InternalLinkage;
     GlobalVariable *NewGlobal =
         new GlobalVariable(M, NewTy, G->isConstant(), Linkage, NewInitializer,
                            "", G, G->getThreadLocalMode());
     NewGlobal->copyAttributesFrom(G);
     NewGlobal->setComdat(G->getComdat());
-    NewGlobal->setAlignment(MinRZ);
+    NewGlobal->setAlignment(MaybeAlign(MinRZ));
     // Don't fold globals with redzones. ODR violation detector and redzone
     // poisoning implicitly creates a dependence on the global's address, so it
     // is no longer valid for it to be marked unnamed_addr.
     NewGlobal->setUnnamedAddr(GlobalValue::UnnamedAddr::None);
 
     // Move null-terminated C strings to "__asan_cstring" section on Darwin.
     if (TargetTriple.isOSBinFormatMachO() && !G->hasSection() &&
         G->isConstant()) {
if (NewGlobal->hasLocalLinkage()) {
           new GlobalVariable(M, IRB.getInt8Ty(), false, Linkage,
                              Constant::getNullValue(IRB.getInt8Ty()),
                              kODRGenPrefix + NameForGlobal, nullptr,
                              NewGlobal->getThreadLocalMode());
 
       // Set meaningful attributes for indicator symbol.
       ODRIndicatorSym->setVisibility(NewGlobal->getVisibility());
       ODRIndicatorSym->setDLLStorageClass(NewGlobal->getDLLStorageClass());
-      ODRIndicatorSym->setAlignment(1);
+      ODRIndicatorSym->setAlignment(Align::None());
       ODRIndicator = ODRIndicatorSym;
     }
 
     Constant *Initializer = ConstantStruct::get(
         GlobalStructTy,
         ConstantExpr::getPointerCast(InstrumentedGlobal, IntptrTy),
         ConstantInt::get(IntptrTy, SizeInBytes),
         ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),

llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp

void HWAddressSanitizer::instrumentGlobal(GlobalVariable *GV, uint8_t Tag) {
 
   auto *NewGV = new GlobalVariable(M, Initializer->getType(), GV->isConstant(),
                                    GlobalValue::ExternalLinkage, Initializer,
                                    GV->getName() + ".hwasan");
   NewGV->copyAttributesFrom(GV);
   NewGV->setLinkage(GlobalValue::PrivateLinkage);
   NewGV->copyMetadata(GV, 0);
   NewGV->setAlignment(
-      std::max(GV->getAlignment(), Mapping.getObjectAlignment()));
+      MaybeAlign(std::max(GV->getAlignment(), Mapping.getObjectAlignment())));
 
   // It is invalid to ICF two globals that have different tags. In the case
   // where the size of the global is a multiple of the tag granularity the
   // contents of the globals may be the same but the tags (i.e. symbol values)
   // may be different, and the symbols are not considered during ICF. In the
   // case where the size is not a multiple of the granularity, the short granule
   // tags would discriminate two globals with different tags, but there would
   // otherwise be nothing stopping such a global from being incorrectly ICF'd
void HWAddressSanitizer::instrumentGlobals() {
 
   auto *NoteTy = StructType::get(Int32Ty, Int32Ty, Int32Ty, Name->getType(),
                                  Int32Ty, Int32Ty);
   auto *Note =
       new GlobalVariable(M, NoteTy, /*isConstantGlobal=*/true,
                          GlobalValue::PrivateLinkage, nullptr, kHwasanNoteName);
   Note->setSection(".note.hwasan.globals");
   Note->setComdat(NoteComdat);
-  Note->setAlignment(4);
+  Note->setAlignment(Align(4));
   Note->setDSOLocal(true);
 
   // The pointers in the note need to be relative so that the note ends up being
   // placed in rodata, which is the standard location for notes.
   auto CreateRelPtr = [&](Constant *Ptr) {
     return ConstantExpr::getTrunc(
         ConstantExpr::getSub(ConstantExpr::getPtrToInt(Ptr, Int64Ty),
                              ConstantExpr::getPtrToInt(Note, Int64Ty)),

llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp

InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
   // Create the counters variable.
   auto *CounterPtr =
       new GlobalVariable(*M, CounterTy, false, Linkage,
                          Constant::getNullValue(CounterTy),
                          getVarName(Inc, getInstrProfCountersVarPrefix()));
   CounterPtr->setVisibility(Visibility);
   CounterPtr->setSection(
       getInstrProfSectionName(IPSK_cnts, TT.getObjectFormat()));
-  CounterPtr->setAlignment(8);
+  CounterPtr->setAlignment(Align(8));
   MaybeSetComdat(CounterPtr);
   CounterPtr->setLinkage(Linkage);
 
   auto *Int8PtrTy = Type::getInt8PtrTy(Ctx);
   // Allocate statically the array of pointers to value profile nodes for
   // the current function.
   Constant *ValuesPtrExpr = ConstantPointerNull::get(Int8PtrTy);
   if (ValueProfileStaticAlloc && !needsRuntimeRegistrationOfSectionRange(TT)) {
     uint64_t NS = 0;
     for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
       NS += PD.NumValueSites[Kind];
     if (NS) {
       ArrayType *ValuesTy = ArrayType::get(Type::getInt64Ty(Ctx), NS);
 
       auto *ValuesVar =
           new GlobalVariable(*M, ValuesTy, false, Linkage,
                              Constant::getNullValue(ValuesTy),
                              getVarName(Inc, getInstrProfValuesVarPrefix()));
       ValuesVar->setVisibility(Visibility);
       ValuesVar->setSection(
           getInstrProfSectionName(IPSK_vals, TT.getObjectFormat()));
-      ValuesVar->setAlignment(8);
+      ValuesVar->setAlignment(Align(8));
       MaybeSetComdat(ValuesVar);
       ValuesPtrExpr =
           ConstantExpr::getBitCast(ValuesVar, Type::getInt8PtrTy(Ctx));
     }
   }
 
   // Create data variable.
   auto *Int16Ty = Type::getInt16Ty(Ctx);

 #define INSTR_PROF_DATA(Type, LLVMType, Name, Init) Init,
 #include "llvm/ProfileData/InstrProfData.inc"
   };
   auto *Data = new GlobalVariable(*M, DataTy, false, Linkage,
                                   ConstantStruct::get(DataTy, DataVals),
                                   getVarName(Inc, getInstrProfDataVarPrefix()));
   Data->setVisibility(Visibility);
   Data->setSection(getInstrProfSectionName(IPSK_data, TT.getObjectFormat()));
-  Data->setAlignment(INSTR_PROF_DATA_ALIGNMENT);
+  Data->setAlignment(Align(INSTR_PROF_DATA_ALIGNMENT));
   MaybeSetComdat(Data);
   Data->setLinkage(Linkage);
 
   PD.RegionCounters = CounterPtr;
   PD.DataVar = Data;
   ProfileDataMap[NamePtr] = PD;
 
   // Mark the data variable as used so that it isn't stripped out.
NamesVar = new GlobalVariable(*M, NamesVal->getType(), true,
                                 GlobalValue::PrivateLinkage, NamesVal,
                                 getInstrProfNamesVarName());
   NamesSize = CompressedNameStr.size();
   NamesVar->setSection(
       getInstrProfSectionName(IPSK_name, TT.getObjectFormat()));
   // On COFF, it's important to reduce the alignment down to 1 to prevent the
   // linker from inserting padding before the start of the names section or
   // between names entries.
-  NamesVar->setAlignment(1);
+  NamesVar->setAlignment(Align::None());
   UsedVars.push_back(NamesVar);
 
   for (auto *NamePtr : ReferencedNames)
     NamePtr->eraseFromParent();
 }
 
 void InstrProfiling::emitRegistration() {
   if (!needsRuntimeRegistrationOfSectionRange(TT))

llvm/lib/Transforms/Instrumentation/Instrumentation.cpp

GlobalVariable *llvm::createPrivateGlobalForString(Module &M, StringRef Str,
   Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
   // We use private linkage for module-local strings. If they can be merged
   // with another one, we set the unnamed_addr attribute.
   GlobalVariable *GV =
       new GlobalVariable(M, StrConst->getType(), true,
                          GlobalValue::PrivateLinkage, StrConst, NamePrefix);
   if (AllowMerging)
     GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
-  GV->setAlignment(1);  // Strings may not be merged w/o setting align 1.
+  GV->setAlignment(Align::None()); // Strings may not be merged w/o setting
+                                   // alignment explicitly.
   return GV;
 }
 
 Comdat *llvm::GetOrCreateFunctionComdat(Function &F, Triple &T,
                                         const std::string &ModuleId) {
   if (auto Comdat = F.getComdat()) return Comdat;
   assert(F.hasName());
   Module *M = F.getParent();

llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp

auto Array = new GlobalVariable(
       *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
       Constant::getNullValue(ArrayTy), "__sancov_gen_");
 
   if (TargetTriple.supportsCOMDAT() && !F.isInterposable())
     if (auto Comdat =
             GetOrCreateFunctionComdat(F, TargetTriple, CurModuleUniqueId))
       Array->setComdat(Comdat);
   Array->setSection(getSectionName(Section));
-  Array->setAlignment(Ty->isPointerTy() ? DL->getPointerSize()
-                                        : Ty->getPrimitiveSizeInBits() / 8);
+  Array->setAlignment(Align(Ty->isPointerTy()
+                                ? DL->getPointerSize()
+                                : Ty->getPrimitiveSizeInBits() / 8));
   GlobalsToAppendToUsed.push_back(Array);
   GlobalsToAppendToCompilerUsed.push_back(Array);
   MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F));
   Array->addMetadata(LLVMContext::MD_associated, *MD);
 
   return Array;
 }
 

llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

if (SplatValue) {
     inferLibFuncAttributes(M, FuncName, *TLI);
 
     // Otherwise we should form a memset_pattern16.  PatternValue is known to be
     // an constant array of 16-bytes.  Plop the value into a mergable global.
     GlobalVariable *GV = new GlobalVariable(*M, PatternValue->getType(), true,
                                             GlobalValue::PrivateLinkage,
                                             PatternValue, ".memset_pattern");
     GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global); // Ok to merge these.
-    GV->setAlignment(16);
+    GV->setAlignment(Align(16));
     Value *PatternPtr = ConstantExpr::getBitCast(GV, Int8PtrTy);
     NewCall = Builder.CreateCall(MSP, {BasePtr, PatternPtr, NumBytes});
   }
 
   LLVM_DEBUG(dbgs() << "  Formed memset: " << *NewCall << "\n"
                     << "    from store to: " << *Ev << " at: " << *TheStore
                     << "\n");
   NewCall->setDebugLoc(TheStore->getDebugLoc());

llvm/lib/Transforms/Utils/Local.cpp

if (auto *GO = dyn_cast<GlobalObject>(V)) {
 
     // If there is a large requested alignment and we can, bump up the alignment
     // of the global.  If the memory we set aside for the global may not be the
     // memory used by the final program then it is impossible for us to reliably
     // enforce the preferred alignment.
     if (!GO->canIncreaseAlignment())
       return Alignment;
 
-    GO->setAlignment(PrefAlign);
+    GO->setAlignment(MaybeAlign(PrefAlign));
     return PrefAlign;
   }
 
   return Alignment;
 }
 
 unsigned llvm::getOrEnforceKnownAlignment(Value *V, unsigned PrefAlign,
                                           const DataLayout &DL,

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

SwitchLookupTable::SwitchLookupTable(
   Constant *Initializer = ConstantArray::get(ArrayTy, TableContents);
 
   Array = new GlobalVariable(M, ArrayTy, /*isConstant=*/true,
                              GlobalVariable::PrivateLinkage, Initializer,
                              "switch.table." + FuncName);
   Array->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
   // Set the alignment to that of an array items. We will be only loading one
   // value out of it.
-  Array->setAlignment(DL.getPrefTypeAlignment(ValueType));
+  Array->setAlignment(Align(DL.getPrefTypeAlignment(ValueType)));
   Kind = ArrayKind;
 }
 
 Value *SwitchLookupTable::BuildLookup(Value *Index, IRBuilder<> &Builder) {
   switch (Kind) {
   case SingleValueKind:
     return SingleValue;
   case LinearMapKind: {

llvm/unittests/IR/ConstantsTest.cpp

TEST(ConstantsTest, BitcastToGEP) {
   auto *G = new GlobalVariable(*M, S, false,
                                GlobalValue::ExternalLinkage, nullptr);
   auto *PtrTy = PointerType::get(i32, 0);
   auto *C = ConstantExpr::getBitCast(G, PtrTy);
   ASSERT_EQ(cast<ConstantExpr>(C)->getOpcode(), Instruction::BitCast);
 }
 
 bool foldFuncPtrAndConstToNull(LLVMContext &Context, Module *TheModule,
-                               uint64_t AndValue, unsigned FunctionAlign = 0) {
+                               uint64_t AndValue,
+                               MaybeAlign FunctionAlign = llvm::None) {
   Type *VoidType(Type::getVoidTy(Context));
   FunctionType *FuncType(FunctionType::get(VoidType, false));
   Function *Func(Function::Create(
       FuncType, GlobalValue::ExternalLinkage, "", TheModule));
 
-  if (FunctionAlign) Func->setAlignment(FunctionAlign);
+  if (FunctionAlign)
+    Func->setAlignment(*FunctionAlign);
 
   IntegerType *ConstantIntType(Type::getInt32Ty(Context));
   ConstantInt *TheConstant(ConstantInt::get(ConstantIntType, AndValue));
 
   Constant *TheConstantExpr(
       ConstantExpr::getPtrToInt(Func, ConstantIntType));
 
 
for (const char* AlignmentString : AlignmentStrings) {
     ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, &TheModule, 2));
   }
 }
 
 TEST(ConstantsTest, FoldFunctionAlign4PtrAlignMultiple) {
   LLVMContext Context;
   Module TheModule("TestModule", Context);
   TheModule.setDataLayout("Fn8");
-  ASSERT_TRUE(foldFuncPtrAndConstToNull(Context, &TheModule, 2, 4));
+  ASSERT_TRUE(foldFuncPtrAndConstToNull(Context, &TheModule, 2, Align(4)));
 }
 
 TEST(ConstantsTest, DontFoldFunctionAlign4PtrAlignIndependent) {
   LLVMContext Context;
   Module TheModule("TestModule", Context);
   TheModule.setDataLayout("Fi8");
-  ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, &TheModule, 2, 4));
+  ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, &TheModule, 2, Align(4)));
 }
 
 TEST(ConstantsTest, DontFoldFunctionPtrIfNoModule) {
   LLVMContext Context;
   // Even though the function is explicitly 4 byte aligned, in the absence of a
   // DataLayout we can't assume that the function pointer is aligned.
-  ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, nullptr, 2, 4));
+  ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, nullptr, 2, Align(4)));
 }
 
 TEST(ConstantsTest, FoldGlobalVariablePtr) {
   LLVMContext Context;
 
   IntegerType *IntType(Type::getInt32Ty(Context));
 
   std::unique_ptr<GlobalVariable> Global(
       new GlobalVariable(IntType, true, GlobalValue::ExternalLinkage));
 
-  Global->setAlignment(4);
+  Global->setAlignment(Align(4));
 
   ConstantInt *TheConstant(ConstantInt::get(IntType, 2));
 
   Constant *TheConstantExpr(
       ConstantExpr::getPtrToInt(Global.get(), IntType));
 
   ASSERT_TRUE(ConstantExpr::get( \
       Instruction::And, TheConstantExpr, TheConstant)->isNullValue());
 }
 
 }  // end anonymous namespace
 }  // end namespace llvm

llvm/unittests/IR/FunctionTest.cpp

TEST(FunctionTest, GetPointerAlignment) {
   EXPECT_EQ(0U, Func->getPointerAlignment(DataLayout("")));
   EXPECT_EQ(1U, Func->getPointerAlignment(DataLayout("Fi8")));
   EXPECT_EQ(1U, Func->getPointerAlignment(DataLayout("Fn8")));
   EXPECT_EQ(2U, Func->getPointerAlignment(DataLayout("Fi16")));
   EXPECT_EQ(2U, Func->getPointerAlignment(DataLayout("Fn16")));
   EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fi32")));
   EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fn32")));
 
-  Func->setAlignment(4U);
+  Func->setAlignment(Align(4));
 
   EXPECT_EQ(0U, Func->getPointerAlignment(DataLayout("")));
   EXPECT_EQ(1U, Func->getPointerAlignment(DataLayout("Fi8")));
   EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fn8")));
   EXPECT_EQ(2U, Func->getPointerAlignment(DataLayout("Fi16")));
   EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fn16")));
   EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fi32")));
   EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fn32")));
 }
 
 } // end namespace