diff --git a/utils/TableGen/SequenceToOffsetTable.h b/utils/TableGen/SequenceToOffsetTable.h
new file mode 100644
index 00000000000..26e705841f2
--- /dev/null
+++ b/utils/TableGen/SequenceToOffsetTable.h
@@ -0,0 +1,123 @@
+//===-- SequenceToOffsetTable.h - Compress similar sequences ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// SequenceToOffsetTable can be used to emit a number of null-terminated
+// sequences as one big array.  Use the same memory when a sequence is a suffix
+// of another.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef TBLGEN_SEQUENCE_TO_OFFSET_TABLE_H
+#define TBLGEN_SEQUENCE_TO_OFFSET_TABLE_H
+
+#include "llvm/Support/raw_ostream.h"
+#include <functional>
+#include <algorithm>
+#include <vector>
+#include <cassert>
+
+namespace llvm {
+
+/// SequenceToOffsetTable - Collect a number of terminated sequences of T.
+/// Compute the layout of a table that contains all the sequences, possibly by
+/// reusing entries.
+///
+/// @param SeqT The sequence container. (vector or string).
+/// @param Less A stable comparator for SeqT elements.
+template<typename SeqT, typename Less = std::less<typename SeqT::value_type> >
+class SequenceToOffsetTable {
+  typedef typename SeqT::value_type ElemT;
+
+  // Define a comparator for SeqT that sorts a suffix immediately before a
+  // sequence with that suffix.
+  struct SeqLess : public std::binary_function<SeqT, SeqT, bool> {
+    Less L;
+    bool operator()(const SeqT &A, const SeqT &B) const {
+      return std::lexicographical_compare(A.rbegin(), A.rend(),
+                                          B.rbegin(), B.rend(), L);
+    }
+  };
+
+  // Keep sequences ordered according to SeqLess so suffixes are easy to find.
+  // Map each sequence to its offset in the table.
+  typedef std::map<SeqT, unsigned, SeqLess> SeqMap;
+
+  // Sequences added so far, with suffixes removed.
+  SeqMap Seqs;
+
+  // Entries in the final table, or 0 before layout was called.
+  unsigned Entries;
+
+  // isSuffix - Returns true if A is a suffix of B.
+  static bool isSuffix(const SeqT &A, const SeqT &B) {
+    return A.size() <= B.size() && std::equal(A.rbegin(), A.rend(), B.rbegin());
+  }
+
+public:
+  SequenceToOffsetTable() : Entries(0) {}
+
+  /// add - Add a sequence to the table.
+  /// This must be called before layout().
+  void add(const SeqT &Seq) {
+    assert(Entries == 0 && "Cannot call add() after layout()");
+    typename SeqMap::iterator I = Seqs.lower_bound(Seq);
+
+    // If SeqMap contains a sequence that has Seq as a suffix, I will be
+    // pointing to it.
+    if (I != Seqs.end() && isSuffix(Seq, I->first))
+      return;
+
+    I = Seqs.insert(I, std::make_pair(Seq, 0u));
+
+    // The entry before I may be a suffix of Seq that can now be erased.
+    if (I != Seqs.begin() && isSuffix((--I)->first, Seq))
+      Seqs.erase(I);
+  }
+
+  /// layout - Computes the final table layout.
+  void layout() {
+    assert(Entries == 0 && "Can only call layout() once");
+    // Lay out the table in Seqs iteration order.
+    for (typename SeqMap::iterator I = Seqs.begin(), E = Seqs.end(); I != E;
+         ++I) {
+      I->second = Entries;
+      // Include space for a terminator.
+      Entries += I->first.size() + 1;
+    }
+  }
+
+  /// get - Returns the offset of Seq in the final table.
+  unsigned get(const SeqT &Seq) const {
+    assert(Entries && "Call layout() before get()");
+    typename SeqMap::const_iterator I = Seqs.lower_bound(Seq);
+    assert(I != Seqs.end() && isSuffix(Seq, I->first) &&
+           "get() called with sequence that wasn't added first");
+    return I->second + (I->first.size() - Seq.size());
+  }
+
+  /// emit - Print out the table as the body of an array initializer.
+  /// Use the Print function to print elements.
+  void emit(raw_ostream &OS, void (*Print)(raw_ostream&, ElemT)) const {
+    assert(Entries && "Call layout() before emit()");
+    for (typename SeqMap::const_iterator I = Seqs.begin(), E = Seqs.end();
+         I != E; ++I) {
+      OS << "  /* " << I->second << " */ ";
+      for (typename SeqT::const_iterator SI = I->first.begin(),
+             SE = I->first.end(); SI != SE; ++SI) {
+        Print(OS, *SI);
+        OS << ", ";
+      }
+      OS << "0,\n";
+    }
+  }
+};
+
+} // end namespace llvm
+
+#endif