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diff --git a/llvm/lib/Target/ARM/ARMBasicBlockInfo.h b/llvm/lib/Target/ARM/ARMBasicBlockInfo.h
new file mode 100644
index 000000000000..13df399ed995
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+++ b/llvm/lib/Target/ARM/ARMBasicBlockInfo.h
@@ -0,0 +1,159 @@
+//===-- ARMBasicBlockInfo.h - Basic Block Information -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Utility functions and data structure for computing block size.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_ARM_ARMBASICBLOCKINFO_H
+#define LLVM_LIB_TARGET_ARM_ARMBASICBLOCKINFO_H
+
+#include "ARMBaseInstrInfo.h"
+#include "ARMMachineFunctionInfo.h"
+#include "llvm/Support/MathExtras.h"
+#include <algorithm>
+#include <cstdint>
+
+namespace llvm {
+
+struct BasicBlockInfo;
+using BBInfoVector = SmallVectorImpl<BasicBlockInfo>;
+
+/// UnknownPadding - Return the worst case padding that could result from
+/// unknown offset bits.  This does not include alignment padding caused by
+/// known offset bits.
+///
+/// @param Alignment alignment
+/// @param KnownBits Number of known low offset bits.
+inline unsigned UnknownPadding(Align Alignment, unsigned KnownBits) {
+  if (KnownBits < Log2(Alignment))
+    return Alignment.value() - (1ull << KnownBits);
+  return 0;
+}
+
+/// BasicBlockInfo - Information about the offset and size of a single
+/// basic block.
+struct BasicBlockInfo {
+  /// Offset - Distance from the beginning of the function to the beginning
+  /// of this basic block.
+  ///
+  /// Offsets are computed assuming worst case padding before an aligned
+  /// block. This means that subtracting basic block offsets always gives a
+  /// conservative estimate of the real distance which may be smaller.
+  ///
+  /// Because worst case padding is used, the computed offset of an aligned
+  /// block may not actually be aligned.
+  unsigned Offset = 0;
+
+  /// Size - Size of the basic block in bytes.  If the block contains
+  /// inline assembly, this is a worst case estimate.
+  ///
+  /// The size does not include any alignment padding whether from the
+  /// beginning of the block, or from an aligned jump table at the end.
+  unsigned Size = 0;
+
+  /// KnownBits - The number of low bits in Offset that are known to be
+  /// 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 > 1, the block terminator contains a .align
+  /// directive, so the end of the block is aligned to PostAlign bytes.
+  Align PostAlign;
+
+  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 Align is
+  /// specified, return the offset the successor block will get if it has
+  /// this alignment.
+  unsigned postOffset(Align Alignment = Align::None()) const {
+    unsigned PO = Offset + Size;
+    const Align PA = std::max(PostAlign, Alignment);
+    if (PA == Align::None())
+      return PO;
+    // Add alignment padding from the terminator.
+    return PO + UnknownPadding(PA, 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(Align Align = Align::None()) const {
+    return std::max(Log2(std::max(PostAlign, Align)), internalKnownBits());
+  }
+};
+
+class ARMBasicBlockUtils {
+
+private:
+  MachineFunction &MF;
+  bool isThumb = false;
+  const ARMBaseInstrInfo *TII = nullptr;
+  SmallVector<BasicBlockInfo, 8> BBInfo;
+
+public:
+  ARMBasicBlockUtils(MachineFunction &MF) : MF(MF) {
+    TII =
+      static_cast<const ARMBaseInstrInfo*>(MF.getSubtarget().getInstrInfo());
+    isThumb = MF.getInfo<ARMFunctionInfo>()->isThumbFunction();
+  }
+
+  void computeAllBlockSizes() {
+    BBInfo.resize(MF.getNumBlockIDs());
+    for (MachineBasicBlock &MBB : MF)
+      computeBlockSize(&MBB);
+  }
+
+  void computeBlockSize(MachineBasicBlock *MBB);
+
+  unsigned getOffsetOf(MachineInstr *MI) const;
+
+  unsigned getOffsetOf(MachineBasicBlock *MBB) const {
+    return BBInfo[MBB->getNumber()].Offset;
+  }
+
+  void adjustBBOffsetsAfter(MachineBasicBlock *MBB);
+
+  void adjustBBSize(MachineBasicBlock *MBB, int Size) {
+    BBInfo[MBB->getNumber()].Size += Size;
+  }
+
+  bool isBBInRange(MachineInstr *MI, MachineBasicBlock *DestBB,
+                   unsigned MaxDisp) const;
+
+  void insert(unsigned BBNum, BasicBlockInfo BBI) {
+    BBInfo.insert(BBInfo.begin() + BBNum, BBI);
+  }
+
+  void clear() { BBInfo.clear(); }
+
+  BBInfoVector &getBBInfo() { return BBInfo; }
+
+};
+
+} // end namespace llvm
+
+#endif // LLVM_LIB_TARGET_ARM_ARMBASICBLOCKINFO_H