[Alignment][NFC] Remove LogAlignment functions

[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/Target/ARM/ARMBasicBlockInfo.cpp

129–131

inline ?

llvm/lib/Target/ARM/ARMConstantIslandPass.cpp

496–497

Remove We measure in log2(bytes).

537

you might want to cache the end bound.

650–651

ditto - remove Alignment is measured in log2(bytes) units.

658

This should be llvm::Align(1);

1025

As discussed, let's make postOffset take an Align to avoid escaping the type system.

1570–1571

(for later) Consider introducing static constexpr llvm::Align llvm::Align::None (or Unaligned)

llvm/lib/Target/Hexagon/HexagonBranchRelaxation.cpp

108

would be useful here: if (B.getAlignment() != Align::None)

[gchatelet]

• Address some of the comments

[gchatelet]

• Address comments

[courbet]

llvm/lib/Target/Hexagon/HexagonFixupHwLoops.cpp

117

use None ?

[gchatelet]

llvm/lib/Target/ARM/ARMConstantIslandPass.cpp

658

Good catch !

llvm/include/llvm/CodeGen/MachineBasicBlock.h

#endif
   /// Get the clobber mask for the start of this basic block. Funclets use this
   /// to prevent register allocation across funclet transitions.
   const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const;
 
   /// Get the clobber mask for the end of the basic block.
   /// \see getBeginClobberMask()
   const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const;
 
-  /// Return alignment of the basic block. The alignment is specified as
-  /// log2(bytes).
-  /// FIXME: Remove the Log versions once migration to llvm::Align is over.
-  unsigned getLogAlignment() const { return Log2(Alignment); }
+  /// Return alignment of the basic block.
   llvm::Align getAlignment() const { return Alignment; }
 
-  /// Set alignment of the basic block. The alignment is specified as
-  /// log2(bytes).
-  /// FIXME: Remove the Log versions once migration to llvm::Align is over.
-  void setLogAlignment(unsigned A) { Alignment = llvm::Align(1ULL << A); }
+  /// Set alignment of the basic block.
   void setAlignment(llvm::Align A) { Alignment = A; }
 
   /// Returns true if the block is a landing pad. That is this basic block is
   /// entered via an exception handler.
   bool isEHPad() const { return IsEHPad; }
 
   /// Indicates the block is a landing pad.  That is this basic block is entered
   /// via an exception handler.

llvm/lib/CodeGen/BranchRelaxation.cpp

 
 INITIALIZE_PASS(BranchRelaxation, DEBUG_TYPE, BRANCH_RELAX_NAME, false, false)
 
 /// verify - check BBOffsets, BBSizes, alignment of islands
 void BranchRelaxation::verify() {
 #ifndef NDEBUG
   unsigned PrevNum = MF->begin()->getNumber();
   for (MachineBasicBlock &MBB : *MF) {
-    unsigned LogAlign = MBB.getLogAlignment();
-    unsigned Num = MBB.getNumber();
-    assert(BlockInfo[Num].Offset % (1u << LogAlign) == 0);
+    const unsigned Num = MBB.getNumber();
+    assert(isAligned(MBB.getAlignment(), BlockInfo[Num].Offset));
     assert(!Num || BlockInfo[PrevNum].postOffset(MBB) <= BlockInfo[Num].Offset);
     assert(BlockInfo[Num].Size == computeBlockSize(MBB));
     PrevNum = Num;
   }
 #endif
 }
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)

llvm/lib/CodeGen/MIRParser/MIParser.cpp

bool MIParser::parseBasicBlockDefinition(
   }
   auto *MBB = MF.CreateMachineBasicBlock(BB);
   MF.insert(MF.end(), MBB);
   bool WasInserted = MBBSlots.insert(std::make_pair(ID, MBB)).second;
   if (!WasInserted)
     return error(Loc, Twine("redefinition of machine basic block with id #") +
                           Twine(ID));
   if (Alignment)
-    MBB->setLogAlignment(Log2_32(Alignment));
+    MBB->setAlignment(llvm::Align(Alignment));
   if (HasAddressTaken)
     MBB->setHasAddressTaken();
   MBB->setIsEHPad(IsLandingPad);
   return false;
 }
 
 bool MIParser::parseBasicBlockDefinitions(
     DenseMap<unsigned, MachineBasicBlock *> &MBBSlots) {

llvm/lib/CodeGen/MIRPrinter.cpp

if (MBB.hasAddressTaken()) {
     OS << "address-taken";
     HasAttributes = true;
   }
   if (MBB.isEHPad()) {
     OS << (HasAttributes ? ", " : " (");
     OS << "landing-pad";
     HasAttributes = true;
   }
-  if (MBB.getLogAlignment()) {
+  if (MBB.getAlignment() > 1) {
     OS << (HasAttributes ? ", " : " (");
-    OS << "align "
-       << (1UL << MBB.getLogAlignment());
+    OS << "align " << MBB.getAlignment().value();
     HasAttributes = true;
   }
   if (HasAttributes)
     OS << ")";
   OS << ":\n";
 
   bool HasLineAttributes = false;
   // Print the successors

llvm/lib/CodeGen/MachineBasicBlock.cpp

if (hasAddressTaken()) {
     OS << "address-taken";
     HasAttributes = true;
   }
   if (isEHPad()) {
     OS << (HasAttributes ? ", " : " (");
     OS << "landing-pad";
     HasAttributes = true;
   }
-  if (getLogAlignment()) {
+  if (getAlignment() > 1) {
     OS << (HasAttributes ? ", " : " (");
-    OS << "align " << getLogAlignment();
+    OS << "align " << Log2(getAlignment());
     HasAttributes = true;
   }
   if (HasAttributes)
     OS << ")";
   OS << ":\n";
 
   const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
   const MachineRegisterInfo &MRI = MF->getRegInfo();

llvm/lib/CodeGen/MachineBlockPlacement.cpp

for (MachineBasicBlock *ChainBB : FunctionChain) {
     // Check for the existence of a non-layout predecessor which would benefit
     // from aligning this block.
     MachineBasicBlock *LayoutPred =
         &*std::prev(MachineFunction::iterator(ChainBB));
 
     // Force alignment if all the predecessors are jumps. We already checked
     // that the block isn't cold above.
     if (!LayoutPred->isSuccessor(ChainBB)) {
-      ChainBB->setLogAlignment(Log2(Align));
+      ChainBB->setAlignment(Align);
       continue;
     }
 
     // Align this block if the layout predecessor's edge into this block is
     // cold relative to the block. When this is true, other predecessors make up
     // all of the hot entries into the block and thus alignment is likely to be
     // important.
     BranchProbability LayoutProb =
         MBPI->getEdgeProbability(LayoutPred, ChainBB);
     BlockFrequency LayoutEdgeFreq = MBFI->getBlockFreq(LayoutPred) * LayoutProb;
     if (LayoutEdgeFreq <= (Freq * ColdProb))
-      ChainBB->setLogAlignment(Log2(Align));
+      ChainBB->setAlignment(Align);
   }
 }
 
 /// Tail duplicate \p BB into (some) predecessors if profitable, repeating if
 /// it was duplicated into its chain predecessor and removed.
 /// \p BB    - Basic block that may be duplicated.
 ///
 /// \p LPred - Chosen layout predecessor of \p BB.
bool MachineBlockPlacement::runOnMachineFunction(MachineFunction &MF) {
 
   BlockToChain.clear();
   ComputedEdges.clear();
   ChainAllocator.DestroyAll();
 
   if (AlignAllBlock)
     // Align all of the blocks in the function to a specific alignment.
     for (MachineBasicBlock &MBB : MF)
-      MBB.setLogAlignment(AlignAllBlock);
+      MBB.setAlignment(llvm::Align(1ULL << AlignAllBlock));
   else if (AlignAllNonFallThruBlocks) {
     // Align all of the blocks that have no fall-through predecessors to a
     // specific alignment.
     for (auto MBI = std::next(MF.begin()), MBE = MF.end(); MBI != MBE; ++MBI) {
       auto LayoutPred = std::prev(MBI);
       if (!LayoutPred->isSuccessor(&*MBI))
-        MBI->setLogAlignment(AlignAllNonFallThruBlocks);
+        MBI->setAlignment(llvm::Align(1ULL << AlignAllNonFallThruBlocks));
     }
   }
   if (ViewBlockLayoutWithBFI != GVDT_None &&
       (ViewBlockFreqFuncName.empty() ||
        F->getFunction().getName().equals(ViewBlockFreqFuncName))) {
     MBFI->view("MBP." + MF.getName(), false);
   }
 

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

llvm::Align SITargetLowering::getPrefLoopAlignment(MachineLoop *ML) const {
   if (Header->getAlignment() != PrefAlign)
     return Header->getAlignment(); // Already processed.
 
   unsigned LoopSize = 0;
   for (const MachineBasicBlock *MBB : ML->blocks()) {
     // If inner loop block is aligned assume in average half of the alignment
     // size to be added as nops.
     if (MBB != Header)
-      LoopSize += (1 << MBB->getLogAlignment()) / 2;
+      LoopSize += MBB->getAlignment().value() / 2;
 
     for (const MachineInstr &MI : *MBB) {
       LoopSize += TII->getInstSizeInBytes(MI);
       if (LoopSize > 192)
         return PrefAlign;
     }
   }
 

llvm/lib/Target/ARM/ARMBasicBlockInfo.h

struct BasicBlockInfo {
   /// exact.  The remaining bits of Offset are an upper bound.
   uint8_t KnownBits = 0;
 
   /// Unalign - When non-zero, the block contains instructions (inline asm)
   /// of unknown size.  The real size may be smaller than Size bytes by a
   /// multiple of 1 << Unalign.
   uint8_t Unalign = 0;
 
-  /// PostAlign - When non-zero, the block terminator contains a .align
-  /// directive, so the end of the block is aligned to 1 << PostAlign
+  /// PostLogAlign - When non-zero, the block terminator contains a .align
+  /// directive, so the end of the block is aligned to 1 << PostLogAlign
   /// bytes.
-  uint8_t PostAlign = 0;
+  uint8_t PostLogAlign = 0;
 
   BasicBlockInfo() = default;
 
   /// Compute the number of known offset bits internally to this block.
   /// This number should be used to predict worst case padding when
   /// splitting the block.
   unsigned internalKnownBits() const {
     unsigned Bits = Unalign ? Unalign : KnownBits;
     // If the block size isn't a multiple of the known bits, assume the
     // worst case padding.
     if (Size & ((1u << Bits) - 1))
       Bits = countTrailingZeros(Size);
     return Bits;
   }
 
   /// Compute the offset immediately following this block.  If LogAlign is
   /// specified, return the offset the successor block will get if it has
   /// this alignment.
   unsigned postOffset(unsigned LogAlign = 0) const {
     unsigned PO = Offset + Size;
-    unsigned LA = std::max(unsigned(PostAlign), LogAlign);
+    unsigned LA = std::max(unsigned(PostLogAlign), LogAlign);
     if (!LA)
       return PO;
     // Add alignment padding from the terminator.
     return PO + UnknownPadding(LA, internalKnownBits());
   }
 
   /// Compute the number of known low bits of postOffset.  If this block
   /// contains inline asm, the number of known bits drops to the
   /// instruction alignment.  An aligned terminator may increase the number
   /// of know bits.
   /// If LogAlign is given, also consider the alignment of the next block.
   unsigned postKnownBits(unsigned LogAlign = 0) const {
-    return std::max(std::max(unsigned(PostAlign), LogAlign),
+    return std::max(std::max(unsigned(PostLogAlign), LogAlign),
                     internalKnownBits());
   }
 };
 
 class ARMBasicBlockUtils {
 
 private:
   MachineFunction &MF;

llvm/lib/Target/ARM/ARMBasicBlockInfo.cpp

mayOptimizeThumb2Instruction(const MachineInstr *MI) {
   return false;
 }
 
 void ARMBasicBlockUtils::computeBlockSize(MachineBasicBlock *MBB) {
   LLVM_DEBUG(dbgs() << "computeBlockSize: " << MBB->getName() << "\n");
   BasicBlockInfo &BBI = BBInfo[MBB->getNumber()];
   BBI.Size = 0;
   BBI.Unalign = 0;
-  BBI.PostAlign = 0;
+  BBI.PostLogAlign = 0;
 
   for (MachineInstr &I : *MBB) {
     BBI.Size += TII->getInstSizeInBytes(I);
     // For inline asm, getInstSizeInBytes returns a conservative estimate.
     // The actual size may be smaller, but still a multiple of the instr size.
     if (I.isInlineAsm())
       BBI.Unalign = isThumb ? 1 : 2;
     // Also consider instructions that may be shrunk later.
     else if (isThumb && mayOptimizeThumb2Instruction(&I))
       BBI.Unalign = 1;
   }
 
   // tBR_JTr contains a .align 2 directive.
   if (!MBB->empty() && MBB->back().getOpcode() == ARM::tBR_JTr) {
-    BBI.PostAlign = 2;
+    BBI.PostLogAlign = 2;
     MBB->getParent()->ensureAlignment(llvm::Align(4));
   }
 }
 
 /// getOffsetOf - Return the current offset of the specified machine instruction
 /// from the start of the function.  This offset changes as stuff is moved
 /// around inside the function.
 unsigned ARMBasicBlockUtils::getOffsetOf(MachineInstr *MI) const {
LLVM_DEBUG(dbgs() << "Adjust block:\n"
              << " - name: " << BB->getName() << "\n"
              << " - number: " << BB->getNumber() << "\n"
              << " - function: " << MF.getName() << "\n"
              << "   - blocks: " << MF.getNumBlockIDs() << "\n");
 
   for(unsigned i = BBNum + 1, e = MF.getNumBlockIDs(); i < e; ++i) {
     // Get the offset and known bits at the end of the layout predecessor.
     // Include the alignment of the current block.
-    unsigned LogAlign = MF.getBlockNumbered(i)->getLogAlignment();
-    unsigned Offset = BBInfo[i - 1].postOffset(LogAlign);
-    unsigned KnownBits = BBInfo[i - 1].postKnownBits(LogAlign);
+    const unsigned LogAlign = Log2(MF.getBlockNumbered(i)->getAlignment());
+    const unsigned Offset = BBInfo[i - 1].postOffset(LogAlign);
+    const unsigned KnownBits = BBInfo[i - 1].postKnownBits(LogAlign);
 
     // This is where block i begins.  Stop if the offset is already correct,
     // and we have updated 2 blocks.  This is the maximum number of blocks
     // changed before calling this function.
     if (i > BBNum + 2 &&
         BBInfo[i].Offset == Offset &&
         BBInfo[i].KnownBits == KnownBits)
       break;
 
     BBInfo[i].Offset = Offset;
     BBInfo[i].KnownBits = KnownBits;
   }
 }
 
 } // end namespace llvm

llvm/lib/Target/ARM/ARMConstantIslandPass.cpp

StringRef getPassName() const override {
       return ARM_CP_ISLANDS_OPT_NAME;
     }
 
   private:
     void doInitialConstPlacement(std::vector<MachineInstr *> &CPEMIs);
     void doInitialJumpTablePlacement(std::vector<MachineInstr *> &CPEMIs);
     bool BBHasFallthrough(MachineBasicBlock *MBB);
     CPEntry *findConstPoolEntry(unsigned CPI, const MachineInstr *CPEMI);
-    unsigned getCPELogAlign(const MachineInstr *CPEMI);
+    llvm::Align getCPEAlign(const MachineInstr *CPEMI);
     void scanFunctionJumpTables();
     void initializeFunctionInfo(const std::vector<MachineInstr*> &CPEMIs);
     MachineBasicBlock *splitBlockBeforeInstr(MachineInstr *MI);
     void updateForInsertedWaterBlock(MachineBasicBlock *NewBB);
     bool decrementCPEReferenceCount(unsigned CPI, MachineInstr* CPEMI);
     unsigned getCombinedIndex(const MachineInstr *CPEMI);
     int findInRangeCPEntry(CPUser& U, unsigned UserOffset);
     bool findAvailableWater(CPUser&U, unsigned UserOffset,

 LLVM_DUMP_METHOD void ARMConstantIslands::dumpBBs() {
   BBInfoVector &BBInfo = BBUtils->getBBInfo();
   LLVM_DEBUG({
     for (unsigned J = 0, E = BBInfo.size(); J !=E; ++J) {
       const BasicBlockInfo &BBI = BBInfo[J];
       dbgs() << format("%08x %bb.%u\t", BBI.Offset, J)
              << " kb=" << unsigned(BBI.KnownBits)
              << " ua=" << unsigned(BBI.Unalign)
-             << " pa=" << unsigned(BBI.PostAlign)
+             << " pa=" << unsigned(BBI.PostLogAlign)
              << format(" size=%#x\n", BBInfo[J].Size);
     }
   });
 }
 #endif
 
 bool ARMConstantIslands::runOnMachineFunction(MachineFunction &mf) {
   MF = &mf;

 
 /// Perform the initial placement of the regular constant pool entries.
 /// To start with, we put them all at the end of the function.
 void
 ARMConstantIslands::doInitialConstPlacement(std::vector<MachineInstr*> &CPEMIs) {
   // Create the basic block to hold the CPE's.
   MachineBasicBlock *BB = MF->CreateMachineBasicBlock();
   MF->push_back(BB);
 
-  // MachineConstantPool measures alignment in bytes. We measure in log2(bytes).
-  unsigned MaxLogAlign = Log2_32(MCP->getConstantPoolAlignment());
+  // MachineConstantPool measures alignment in bytes.
+  const llvm::Align MaxAlign(MCP->getConstantPoolAlignment());
 
   // Mark the basic block as required by the const-pool.
-  BB->setLogAlignment(MaxLogAlign);
+  BB->setAlignment(MaxAlign);
 
   // The function needs to be as aligned as the basic blocks. The linker may
   // move functions around based on their alignment.
   MF->ensureAlignment(BB->getAlignment());
 
   // Order the entries in BB by descending alignment.  That ensures correct
   // alignment of all entries as long as BB is sufficiently aligned.  Keep
   // track of the insertion point for each alignment.  We are going to bucket
   // sort the entries as they are created.
-  SmallVector<MachineBasicBlock::iterator, 8> InsPoint(MaxLogAlign + 1,
+  SmallVector<MachineBasicBlock::iterator, 8> InsPoint(Log2(MaxAlign) + 1,
                                                        BB->end());
 
   // Add all of the constants from the constant pool to the end block, use an
   // identity mapping of CPI's to CPE's.
   const std::vector<MachineConstantPoolEntry> &CPs = MCP->getConstants();
 
   const DataLayout &TD = MF->getDataLayout();
   for (unsigned i = 0, e = CPs.size(); i != e; ++i) {
for (unsigned i = 0, e = CPs.size(); i != e; ++i) {
     MachineBasicBlock::iterator InsAt = InsPoint[LogAlign];
     MachineInstr *CPEMI =
       BuildMI(*BB, InsAt, DebugLoc(), TII->get(ARM::CONSTPOOL_ENTRY))
         .addImm(i).addConstantPoolIndex(i).addImm(Size);
     CPEMIs.push_back(CPEMI);
 
     // Ensure that future entries with higher alignment get inserted before
     // CPEMI. This is bucket sort with iterators.
-    for (unsigned a = LogAlign + 1; a <= MaxLogAlign; ++a)
+    for (unsigned a = LogAlign + 1; a <= Log2(MaxAlign); ++a)
       if (InsPoint[a] == InsAt)
         InsPoint[a] = CPEMI;
 
     // Add a new CPEntry, but no corresponding CPUser yet.
     CPEntries.emplace_back(1, CPEntry(CPEMI, i));
     ++NumCPEs;
     LLVM_DEBUG(dbgs() << "Moved CPI#" << i << " to end of function, size = "
                       << Size << ", align = " << Align << '\n');
ARMConstantIslands::findConstPoolEntry(unsigned CPI,
   // Number of entries per constpool index should be small, just do a
   // linear search.
   for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
     if (CPEs[i].CPEMI == CPEMI)
       return &CPEs[i];
   }
   return nullptr;
 }
 
-/// getCPELogAlign - Returns the required alignment of the constant pool entry
-/// represented by CPEMI.  Alignment is measured in log2(bytes) units.
-unsigned ARMConstantIslands::getCPELogAlign(const MachineInstr *CPEMI) {
+/// getCPEAlign - Returns the required alignment of the constant pool entry
+/// represented by CPEMI.
+llvm::Align ARMConstantIslands::getCPEAlign(const MachineInstr *CPEMI) {
   switch (CPEMI->getOpcode()) {
   case ARM::CONSTPOOL_ENTRY:
     break;
   case ARM::JUMPTABLE_TBB:
-    return isThumb1 ? 2 : 0;
+    return isThumb1 ? llvm::Align(4) : llvm::Align(1);
   case ARM::JUMPTABLE_TBH:
-    return isThumb1 ? 2 : 1;
+    return isThumb1 ? llvm::Align(4) : llvm::Align(2);
   case ARM::JUMPTABLE_INSTS:
-    return 1;
+    return llvm::Align(2);
   case ARM::JUMPTABLE_ADDRS:
-    return 2;
+    return llvm::Align(4);
   default:
     llvm_unreachable("unknown constpool entry kind");
   }
 
   unsigned CPI = getCombinedIndex(CPEMI);
   assert(CPI < MCP->getConstants().size() && "Invalid constant pool index.");
-  unsigned Align = MCP->getConstants()[CPI].getAlignment();
-  assert(isPowerOf2_32(Align) && "Invalid CPE alignment");
-  return Log2_32(Align);
+  return llvm::Align(MCP->getConstants()[CPI].getAlignment());
 }
 
 /// scanFunctionJumpTables - Do a scan of the function, building up
 /// information about the sizes of each block and the locations of all
 /// the jump tables.
 void ARMConstantIslands::scanFunctionJumpTables() {
   for (MachineBasicBlock &MBB : *MF) {
     for (MachineInstr &I : MBB)

 /// isWaterInRange - Returns true if a CPE placed after the specified
 /// Water (a basic block) will be in range for the specific MI.
 ///
 /// Compute how much the function will grow by inserting a CPE after Water.
 bool ARMConstantIslands::isWaterInRange(unsigned UserOffset,
                                         MachineBasicBlock* Water, CPUser &U,
                                         unsigned &Growth) {
   BBInfoVector &BBInfo = BBUtils->getBBInfo();
-  unsigned CPELogAlign = getCPELogAlign(U.CPEMI);
+  const unsigned CPELogAlign = Log2(getCPEAlign(U.CPEMI));
   unsigned CPEOffset = BBInfo[Water->getNumber()].postOffset(CPELogAlign);
   unsigned NextBlockOffset;
   llvm::Align NextBlockAlignment;
   MachineFunction::const_iterator NextBlock = Water->getIterator();
   if (++NextBlock == MF->end()) {
     NextBlockOffset = BBInfo[Water->getNumber()].postOffset();
   } else {
     NextBlockOffset = BBInfo[NextBlock->getNumber()].Offset;
     NextBlockAlignment = NextBlock->getAlignment();
bool ARMConstantIslands::findAvailableWater(CPUser &U, unsigned UserOffset,
   //   BB0:
   //      Big BB
   //   BB1:
   //      Constant Pool
   // When a CP access is out of range, BB0 may be used as water. However,
   // inserting islands between BB0 and BB1 makes other accesses out of range.
   MachineBasicBlock *UserBB = U.MI->getParent();
   BBInfoVector &BBInfo = BBUtils->getBBInfo();
-  unsigned MinNoSplitDisp =
-      BBInfo[UserBB->getNumber()].postOffset(getCPELogAlign(U.CPEMI));
+  const unsigned LogAlign = Log2(getCPEAlign(U.CPEMI));
+  unsigned MinNoSplitDisp = BBInfo[UserBB->getNumber()].postOffset(LogAlign);
   if (CloserWater && MinNoSplitDisp > U.getMaxDisp() / 2)
     return false;
   for (water_iterator IP = std::prev(WaterList.end()), B = WaterList.begin();;
        --IP) {
     MachineBasicBlock* WaterBB = *IP;
     // Check if water is in range and is either at a lower address than the
     // current "high water mark" or a new water block that was created since
     // the previous iteration by inserting an unconditional branch.  In the

 /// block following which the new island can be inserted (the WaterList
 /// is not adjusted).
 void ARMConstantIslands::createNewWater(unsigned CPUserIndex,
                                         unsigned UserOffset,
                                         MachineBasicBlock *&NewMBB) {
   CPUser &U = CPUsers[CPUserIndex];
   MachineInstr *UserMI = U.MI;
   MachineInstr *CPEMI  = U.CPEMI;
-  unsigned CPELogAlign = getCPELogAlign(CPEMI);
+  const unsigned CPELogAlign = Log2(getCPEAlign(CPEMI));
   MachineBasicBlock *UserMBB = UserMI->getParent();
   BBInfoVector &BBInfo = BBUtils->getBBInfo();
   const BasicBlockInfo &UserBBI = BBInfo[UserMBB->getNumber()];
 
   // If the block does not end in an unconditional branch already, and if the
   // end of the block is within range, make new water there.  (The addition
   // below is for the unconditional branch we will be adding: 4 bytes on ARM +
   // Thumb2, 2 on Thumb1.
if (IP != WaterList.end())
       NewWaterList.erase(WaterBB);
 
     // We are adding new water.  Update NewWaterList.
     NewWaterList.insert(NewIsland);
   }
   // Always align the new block because CP entries can be smaller than 4
   // bytes. Be careful not to decrease the existing alignment, e.g. NewMBB may
   // be an already aligned constant pool block.
-  const unsigned LogAlign = isThumb ? 1 : 2;
-  if (NewMBB->getLogAlignment() < LogAlign)
-    NewMBB->setLogAlignment(LogAlign);
+  const llvm::Align Align = isThumb ? llvm::Align(2) : llvm::Align(4);
+  if (NewMBB->getAlignment() < Align)
+    NewMBB->setAlignment(Align);
 
   // Remove the original WaterList entry; we want subsequent insertions in
   // this vicinity to go after the one we're about to insert.  This
   // considerably reduces the number of times we have to move the same CPE
   // more than once and is also important to ensure the algorithm terminates.
   if (IP != WaterList.end())
     WaterList.erase(IP);
 
U.CPEMI = BuildMI(NewIsland, DebugLoc(), CPEMI->getDesc())
                 .addImm(Size);
   CPEntries[CPI].push_back(CPEntry(U.CPEMI, ID, 1));
   ++NumCPEs;
 
   // Decrement the old entry, and remove it if refcount becomes 0.
   decrementCPEReferenceCount(CPI, CPEMI);
 
   // Mark the basic block as aligned as required by the const-pool entry.
-  NewIsland->setLogAlignment(getCPELogAlign(U.CPEMI));
+  NewIsland->setAlignment(getCPEAlign(U.CPEMI));
 
   // Increase the size of the island block to account for the new entry.
   BBUtils->adjustBBSize(NewIsland, Size);
   BBUtils->adjustBBOffsetsAfter(&*--NewIsland->getIterator());
 
   // Finally, change the CPI in the instruction operand to be ID.
   for (unsigned i = 0, e = UserMI->getNumOperands(); i != e; ++i)
     if (UserMI->getOperand(i).isCPI()) {
void ARMConstantIslands::removeDeadCPEMI(MachineInstr *CPEMI) {
   CPEMI->eraseFromParent();
   BBInfoVector &BBInfo = BBUtils->getBBInfo();
   BBUtils->adjustBBSize(CPEBB, -Size);
   // All succeeding offsets have the current size value added in, fix this.
   if (CPEBB->empty()) {
     BBInfo[CPEBB->getNumber()].Size = 0;
 
     // This block no longer needs to be aligned.
-    CPEBB->setLogAlignment(0);
-  } else
+    CPEBB->setAlignment(llvm::Align(1));
+  } else {
     // Entries are sorted by descending alignment, so realign from the front.
-    CPEBB->setLogAlignment(getCPELogAlign(&*CPEBB->begin()));
+    CPEBB->setAlignment(getCPEAlign(&*CPEBB->begin()));
+  }
 
   BBUtils->adjustBBOffsetsAfter(CPEBB);
   // An island has only one predecessor BB and one successor BB. Check if
   // this BB's predecessor jumps directly to this BB's successor. This
   // shouldn't happen currently.
   assert(!BBIsJumpedOver(CPEBB) && "How did this happen?");
   // FIXME: remove the empty blocks after all the work is done?
 }

llvm/lib/Target/Hexagon/HexagonBranchRelaxation.cpp

bool HexagonBranchRelaxation::runOnMachineFunction(MachineFunction &MF) {
   return Changed;
 }
 
 void HexagonBranchRelaxation::computeOffset(MachineFunction &MF,
       DenseMap<MachineBasicBlock*, unsigned> &OffsetMap) {
   // offset of the current instruction from the start.
   unsigned InstOffset = 0;
   for (auto &B : MF) {
-    if (B.getLogAlignment()) {
+    if (B.getAlignment() > 1) {
       // Although we don't know the exact layout of the final code, we need
       // to account for alignment padding somehow. This heuristic pads each
       // aligned basic block according to the alignment value.
-      int ByteAlign = (1u << B.getLogAlignment()) - 1;
-      InstOffset = (InstOffset + ByteAlign) & ~(ByteAlign);
+      InstOffset = alignTo(InstOffset, B.getAlignment());
     }
     OffsetMap[&B] = InstOffset;
     for (auto &MI : B.instrs()) {
       InstOffset += HII->getSize(MI);
       // Assume that all extendable branches will be extended.
       if (MI.isBranch() && HII->isExtendable(MI))
         InstOffset += HEXAGON_INSTR_SIZE;
     }

llvm/lib/Target/Hexagon/HexagonFixupHwLoops.cpp

bool HexagonFixupHwLoops::fixupLoopInstrs(MachineFunction &MF) {
   // Map for each basic block to it's first instruction.
   DenseMap<const MachineBasicBlock *, unsigned> BlockToInstOffset;
 
   const HexagonInstrInfo *HII =
       static_cast<const HexagonInstrInfo *>(MF.getSubtarget().getInstrInfo());
 
   // First pass - compute the offset of each basic block.
   for (const MachineBasicBlock &MBB : MF) {
-    if (MBB.getLogAlignment()) {
+    if (MBB.getAlignment() > 1) {
       // Although we don't know the exact layout of the final code, we need
       // to account for alignment padding somehow. This heuristic pads each
       // aligned basic block according to the alignment value.
-      int ByteAlign = (1u << MBB.getLogAlignment()) - 1;
-      InstOffset = (InstOffset + ByteAlign) & ~(ByteAlign);
+      InstOffset = alignTo(InstOffset, MBB.getAlignment());
     }
 
     BlockToInstOffset[&MBB] = InstOffset;
     for (const MachineInstr &MI : MBB)
       InstOffset += HII->getSize(MI);
   }
 
   // Second pass - check each loop instruction to see if it needs to be

llvm/lib/Target/Mips/MipsConstantIslandPass.cpp

public:
 
     MachineFunctionProperties getRequiredProperties() const override {
       return MachineFunctionProperties().set(
           MachineFunctionProperties::Property::NoVRegs);
     }
 
     void doInitialPlacement(std::vector<MachineInstr*> &CPEMIs);
     CPEntry *findConstPoolEntry(unsigned CPI, const MachineInstr *CPEMI);
-    unsigned getCPELogAlign(const MachineInstr &CPEMI);
+    llvm::Align getCPEAlign(const MachineInstr &CPEMI);
     void initializeFunctionInfo(const std::vector<MachineInstr*> &CPEMIs);
     unsigned getOffsetOf(MachineInstr *MI) const;
     unsigned getUserOffset(CPUser&) const;
     void dumpBBs();
 
     bool isOffsetInRange(unsigned UserOffset, unsigned TrialOffset,
                          unsigned Disp, bool NegativeOK);
     bool isOffsetInRange(unsigned UserOffset, unsigned TrialOffset,

 /// entries.  To start with, we put them all at the end of the function.
 void
 MipsConstantIslands::doInitialPlacement(std::vector<MachineInstr*> &CPEMIs) {
   // Create the basic block to hold the CPE's.
   MachineBasicBlock *BB = MF->CreateMachineBasicBlock();
   MF->push_back(BB);
 
   // MachineConstantPool measures alignment in bytes. We measure in log2(bytes).
-  unsigned MaxLogAlign = Log2_32(MCP->getConstantPoolAlignment());
+  const llvm::Align MaxAlign(MCP->getConstantPoolAlignment());
 
   // Mark the basic block as required by the const-pool.
   // If AlignConstantIslands isn't set, use 4-byte alignment for everything.
-  BB->setLogAlignment(AlignConstantIslands ? MaxLogAlign : 2);
+  BB->setAlignment(AlignConstantIslands ? MaxAlign : llvm::Align(4));
 
   // The function needs to be as aligned as the basic blocks. The linker may
   // move functions around based on their alignment.
   MF->ensureAlignment(BB->getAlignment());
 
   // Order the entries in BB by descending alignment.  That ensures correct
   // alignment of all entries as long as BB is sufficiently aligned.  Keep
   // track of the insertion point for each alignment.  We are going to bucket
   // sort the entries as they are created.
-  SmallVector<MachineBasicBlock::iterator, 8> InsPoint(MaxLogAlign + 1,
+  SmallVector<MachineBasicBlock::iterator, 8> InsPoint(Log2(MaxAlign) + 1,
                                                        BB->end());
 
   // Add all of the constants from the constant pool to the end block, use an
   // identity mapping of CPI's to CPE's.
   const std::vector<MachineConstantPoolEntry> &CPs = MCP->getConstants();
 
   const DataLayout &TD = MF->getDataLayout();
   for (unsigned i = 0, e = CPs.size(); i != e; ++i) {
for (unsigned i = 0, e = CPs.size(); i != e; ++i) {
     MachineInstr *CPEMI =
       BuildMI(*BB, InsAt, DebugLoc(), TII->get(Mips::CONSTPOOL_ENTRY))
         .addImm(i).addConstantPoolIndex(i).addImm(Size);
 
     CPEMIs.push_back(CPEMI);
 
     // Ensure that future entries with higher alignment get inserted before
     // CPEMI. This is bucket sort with iterators.
-    for (unsigned a = LogAlign + 1; a <= MaxLogAlign; ++a)
+    for (unsigned a = LogAlign + 1; a <= Log2(MaxAlign); ++a)
       if (InsPoint[a] == InsAt)
         InsPoint[a] = CPEMI;
     // Add a new CPEntry, but no corresponding CPUser yet.
     CPEntries.emplace_back(1, CPEntry(CPEMI, i));
     ++NumCPEs;
     LLVM_DEBUG(dbgs() << "Moved CPI#" << i << " to end of function, size = "
                       << Size << ", align = " << Align << '\n');
   }
*MipsConstantIslands::findConstPoolEntry(unsigned CPI,
   // linear search.
   for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
     if (CPEs[i].CPEMI == CPEMI)
       return &CPEs[i];
   }
   return nullptr;
 }
 
-/// getCPELogAlign - Returns the required alignment of the constant pool entry
+/// getCPEAlign - Returns the required alignment of the constant pool entry
 /// represented by CPEMI.  Alignment is measured in log2(bytes) units.
-unsigned MipsConstantIslands::getCPELogAlign(const MachineInstr &CPEMI) {
+llvm::Align MipsConstantIslands::getCPEAlign(const MachineInstr &CPEMI) {
   assert(CPEMI.getOpcode() == Mips::CONSTPOOL_ENTRY);
 
   // Everything is 4-byte aligned unless AlignConstantIslands is set.
   if (!AlignConstantIslands)
-    return 2;
+    return llvm::Align(4);
 
   unsigned CPI = CPEMI.getOperand(1).getIndex();
   assert(CPI < MCP->getConstants().size() && "Invalid constant pool index.");
-  unsigned Align = MCP->getConstants()[CPI].getAlignment();
-  assert(isPowerOf2_32(Align) && "Invalid CPE alignment");
-  return Log2_32(Align);
+  return llvm::Align(MCP->getConstants()[CPI].getAlignment());
 }
 
 /// initializeFunctionInfo - Do the initial scan of the function, building up
 /// information about the sizes of each block, the location of all the water,
 /// and finding all of the constant pool users.
 void MipsConstantIslands::
 initializeFunctionInfo(const std::vector<MachineInstr*> &CPEMIs) {
   BBInfo.clear();

 
 /// isWaterInRange - Returns true if a CPE placed after the specified
 /// Water (a basic block) will be in range for the specific MI.
 ///
 /// Compute how much the function will grow by inserting a CPE after Water.
 bool MipsConstantIslands::isWaterInRange(unsigned UserOffset,
                                         MachineBasicBlock* Water, CPUser &U,
                                         unsigned &Growth) {
-  unsigned CPELogAlign = getCPELogAlign(*U.CPEMI);
+  unsigned CPELogAlign = Log2(getCPEAlign(*U.CPEMI));
   unsigned CPEOffset = BBInfo[Water->getNumber()].postOffset(CPELogAlign);
   unsigned NextBlockOffset;
   llvm::Align NextBlockAlignment;
   MachineFunction::const_iterator NextBlock = ++Water->getIterator();
   if (NextBlock == MF->end()) {
     NextBlockOffset = BBInfo[Water->getNumber()].postOffset();
     NextBlockAlignment = llvm::Align();
   } else {

 /// block following which the new island can be inserted (the WaterList
 /// is not adjusted).
 void MipsConstantIslands::createNewWater(unsigned CPUserIndex,
                                         unsigned UserOffset,
                                         MachineBasicBlock *&NewMBB) {
   CPUser &U = CPUsers[CPUserIndex];
   MachineInstr *UserMI = U.MI;
   MachineInstr *CPEMI  = U.CPEMI;
-  unsigned CPELogAlign = getCPELogAlign(*CPEMI);
+  const unsigned CPELogAlign = Log2(getCPEAlign(*CPEMI));
   MachineBasicBlock *UserMBB = UserMI->getParent();
   const BasicBlockInfo &UserBBI = BBInfo[UserMBB->getNumber()];
 
   // If the block does not end in an unconditional branch already, and if the
   // end of the block is within range, make new water there.
   if (BBHasFallthrough(UserMBB)) {
     // Size of branch to insert.
     unsigned Delta = 2;
bool MipsConstantIslands::handleConstantPoolUser(unsigned CPUserIndex) {
   // add it to the island.
   U.HighWaterMark = NewIsland;
   U.CPEMI = BuildMI(NewIsland, DebugLoc(), TII->get(Mips::CONSTPOOL_ENTRY))
                 .addImm(ID).addConstantPoolIndex(CPI).addImm(Size);
   CPEntries[CPI].push_back(CPEntry(U.CPEMI, ID, 1));
   ++NumCPEs;
 
   // Mark the basic block as aligned as required by the const-pool entry.
-  NewIsland->setLogAlignment(getCPELogAlign(*U.CPEMI));
+  NewIsland->setAlignment(getCPEAlign(*U.CPEMI));
 
   // Increase the size of the island block to account for the new entry.
   BBInfo[NewIsland->getNumber()].Size += Size;
   adjustBBOffsetsAfter(&*--NewIsland->getIterator());
 
   // Finally, change the CPI in the instruction operand to be ID.
   for (unsigned i = 0, e = UserMI->getNumOperands(); i != e; ++i)
     if (UserMI->getOperand(i).isCPI()) {
void MipsConstantIslands::removeDeadCPEMI(MachineInstr *CPEMI) {
   unsigned Size = CPEMI->getOperand(2).getImm();
   CPEMI->eraseFromParent();
   BBInfo[CPEBB->getNumber()].Size -= Size;
   // All succeeding offsets have the current size value added in, fix this.
   if (CPEBB->empty()) {
     BBInfo[CPEBB->getNumber()].Size = 0;
 
     // This block no longer needs to be aligned.
-    CPEBB->setLogAlignment(0);
-  } else
+    CPEBB->setAlignment(llvm::Align(1));
+  } else {
     // Entries are sorted by descending alignment, so realign from the front.
-    CPEBB->setLogAlignment(getCPELogAlign(*CPEBB->begin()));
+    CPEBB->setAlignment(getCPEAlign(*CPEBB->begin()));
+  }
 
   adjustBBOffsetsAfter(CPEBB);
   // An island has only one predecessor BB and one successor BB. Check if
   // this BB's predecessor jumps directly to this BB's successor. This
   // shouldn't happen currently.
   assert(!BBIsJumpedOver(CPEBB) && "How did this happen?");
   // FIXME: remove the empty blocks after all the work is done?
 }
else {
     // just reducing the bits by 1 as I've done is correct.
     // The basic block we are branching too much be longword aligned.
     // we know that RA is saved because we always save it right now.
     // this requirement will be relaxed later but we also have an alternate
     // way to implement this that I will implement that does not need jal.
     // We should have a way to back out this alignment restriction if we "can" later.
     // but it is not harmful.
     //
-    DestBB->setLogAlignment(2);
+    DestBB->setAlignment(llvm::Align(4));
     Br.MaxDisp = ((1<<24)-1) * 2;
     MI->setDesc(TII->get(Mips::JalB16));
   }
   BBInfo[MBB->getNumber()].Size += 2;
   adjustBBOffsetsAfter(MBB);
   HasFarJump = true;
   ++NumUBrFixed;
 

llvm/lib/Target/PowerPC/PPCBranchSelector.cpp

 
 /// Determine the offset from the branch in Src block to the Dest block.
 /// BrOffset is the offset of the branch instruction inside Src block.
 int PPCBSel::computeBranchSize(MachineFunction &Fn,
                                const MachineBasicBlock *Src,
                                const MachineBasicBlock *Dest,
                                unsigned BrOffset) {
   int BranchSize;
-  unsigned MaxLogAlign = 2;
+  llvm::Align MaxAlign = llvm::Align(4);
   bool NeedExtraAdjustment = false;
   if (Dest->getNumber() <= Src->getNumber()) {
     // If this is a backwards branch, the delta is the offset from the
     // start of this block to this branch, plus the sizes of all blocks
     // from this block to the dest.
     BranchSize = BrOffset;
-    MaxLogAlign = std::max(MaxLogAlign, Src->getLogAlignment());
+    MaxAlign = std::max(MaxAlign, Src->getAlignment());
 
     int DestBlock = Dest->getNumber();
     BranchSize += BlockSizes[DestBlock].first;
     for (unsigned i = DestBlock+1, e = Src->getNumber(); i < e; ++i) {
       BranchSize += BlockSizes[i].first;
-      MaxLogAlign =
-          std::max(MaxLogAlign, Fn.getBlockNumbered(i)->getLogAlignment());
+      MaxAlign = std::max(MaxAlign, Fn.getBlockNumbered(i)->getAlignment());
     }
 
     NeedExtraAdjustment = (FirstImpreciseBlock >= 0) &&
                           (DestBlock >= FirstImpreciseBlock);
   } else {
     // Otherwise, add the size of the blocks between this block and the
     // dest to the number of bytes left in this block.
     unsigned StartBlock = Src->getNumber();
     BranchSize = BlockSizes[StartBlock].first - BrOffset;
 
-    MaxLogAlign = std::max(MaxLogAlign, Dest->getLogAlignment());
+    MaxAlign = std::max(MaxAlign, Dest->getAlignment());
     for (unsigned i = StartBlock+1, e = Dest->getNumber(); i != e; ++i) {
       BranchSize += BlockSizes[i].first;
-      MaxLogAlign =
-          std::max(MaxLogAlign, Fn.getBlockNumbered(i)->getLogAlignment());
+      MaxAlign = std::max(MaxAlign, Fn.getBlockNumbered(i)->getAlignment());
     }
 
     NeedExtraAdjustment = (FirstImpreciseBlock >= 0) &&
                           (Src->getNumber() >= FirstImpreciseBlock);
   }
 
   // We tend to over estimate code size due to large alignment and
   // inline assembly. Usually it causes larger computed branch offset.
int PPCBSel::computeBranchSize(MachineFunction &Fn,
   // is at most <delta> more than estimated padding bytes. So the actual
   // aligned block address is less than or equal to the estimated aligned
   // block address. So the actual branch offset is less than or equal to
   // computed branch offset.
   //
   // The computed offset is at most ((1 << alignment) - 4) bytes smaller
   // than actual offset. So we add this number to the offset for safety.
   if (NeedExtraAdjustment)
-    BranchSize += (1 << MaxLogAlign) - 4;
+    BranchSize += MaxAlign.value() - 4;
 
   return BranchSize;
 }
 
 bool PPCBSel::runOnMachineFunction(MachineFunction &Fn) {
   const PPCInstrInfo *TII =
       static_cast<const PPCInstrInfo *>(Fn.getSubtarget().getInstrInfo());
   // Give the blocks of the function a dense, in-order, numbering.

llvm/lib/Target/SystemZ/SystemZLongBranch.cpp

 struct MBBInfo {
   // The address that we currently assume the block has.
   uint64_t Address = 0;
 
   // The size of the block in bytes, excluding terminators.
   // This value never changes.
   uint64_t Size = 0;
 
-  // The minimum alignment of the block, as a log2 value.
+  // The minimum alignment of the block.
   // This value never changes.
-  unsigned LogAlignment = 0;
+  llvm::Align Alignment;
 
   // The number of terminators in this block.  This value never changes.
   unsigned NumTerminators = 0;
 
   MBBInfo() = default;
 };
 
 // Represents the state of a block terminator.

 
 } // end anonymous namespace
 
 // Position describes the state immediately before Block.  Update Block
 // accordingly and move Position to the end of the block's non-terminator
 // instructions.
 void SystemZLongBranch::skipNonTerminators(BlockPosition &Position,
                                            MBBInfo &Block) {
-  if (Block.LogAlignment > Position.KnownBits) {
+  if (Log2(Block.Alignment) > Position.KnownBits) {
     // When calculating the address of Block, we need to conservatively
     // assume that Block had the worst possible misalignment.
-    Position.Address += ((uint64_t(1) << Block.LogAlignment) -
-                         (uint64_t(1) << Position.KnownBits));
-    Position.KnownBits = Block.LogAlignment;
+    Position.Address +=
+        (Block.Alignment.value() - (uint64_t(1) << Position.KnownBits));
+    Position.KnownBits = Log2(Block.Alignment);
   }
 
   // Align the addresses.
-  uint64_t AlignMask = (uint64_t(1) << Block.LogAlignment) - 1;
-  Position.Address = (Position.Address + AlignMask) & ~AlignMask;
+  Position.Address = alignTo(Position.Address, Block.Alignment);
 
   // Record the block's position.
   Block.Address = Position.Address;
 
   // Move past the non-terminators in the block.
   Position.Address += Block.Size;
 }
 
uint64_t SystemZLongBranch::initMBBInfo() {
   Terminators.reserve(NumBlocks);
 
   BlockPosition Position(Log2(MF->getAlignment()));
   for (unsigned I = 0; I < NumBlocks; ++I) {
     MachineBasicBlock *MBB = MF->getBlockNumbered(I);
     MBBInfo &Block = MBBs[I];
 
     // Record the alignment, for quick access.
-    Block.LogAlignment = MBB->getLogAlignment();
+    Block.Alignment = MBB->getAlignment();
 
     // Calculate the size of the fixed part of the block.
     MachineBasicBlock::iterator MI = MBB->begin();
     MachineBasicBlock::iterator End = MBB->end();
     while (MI != End && !MI->isTerminator()) {
       Block.Size += TII->getInstSizeInBytes(*MI);
       ++MI;
     }

llvm/lib/Target/X86/X86RetpolineThunks.cpp

void X86RetpolineThunks::populateThunk(MachineFunction &MF,
   BuildMI(CaptureSpec, DebugLoc(), TII->get(X86::PAUSE));
   BuildMI(CaptureSpec, DebugLoc(), TII->get(X86::LFENCE));
   BuildMI(CaptureSpec, DebugLoc(), TII->get(X86::JMP_1)).addMBB(CaptureSpec);
   CaptureSpec->setHasAddressTaken();
   CaptureSpec->addSuccessor(CaptureSpec);
 
   CallTarget->addLiveIn(Reg);
   CallTarget->setHasAddressTaken();
-  CallTarget->setLogAlignment(4);
+  CallTarget->setAlignment(llvm::Align(16));
   insertRegReturnAddrClobber(*CallTarget, Reg);
   CallTarget->back().setPreInstrSymbol(MF, TargetSym);
   BuildMI(CallTarget, DebugLoc(), TII->get(RetOpc));
 }