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diff --git a/deps/v8/src/compiler/backend/gap-resolver.cc b/deps/v8/src/compiler/backend/gap-resolver.cc
new file mode 100644
index 0000000000..6cb7d7fbaf
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+++ b/deps/v8/src/compiler/backend/gap-resolver.cc
@@ -0,0 +1,270 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/compiler/backend/gap-resolver.h"
+
+#include <algorithm>
+#include <set>
+
+#include "src/base/enum-set.h"
+#include "src/register-configuration.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+namespace {
+
+// Splits a FP move between two location operands into the equivalent series of
+// moves between smaller sub-operands, e.g. a double move to two single moves.
+// This helps reduce the number of cycles that would normally occur under FP
+// aliasing, and makes swaps much easier to implement.
+MoveOperands* Split(MoveOperands* move, MachineRepresentation smaller_rep,
+                    ParallelMove* moves) {
+  DCHECK(!kSimpleFPAliasing);
+  // Splitting is only possible when the slot size is the same as float size.
+  DCHECK_EQ(kSystemPointerSize, kFloatSize);
+  const LocationOperand& src_loc = LocationOperand::cast(move->source());
+  const LocationOperand& dst_loc = LocationOperand::cast(move->destination());
+  MachineRepresentation dst_rep = dst_loc.representation();
+  DCHECK_NE(smaller_rep, dst_rep);
+  auto src_kind = src_loc.location_kind();
+  auto dst_kind = dst_loc.location_kind();
+
+  int aliases =
+      1 << (ElementSizeLog2Of(dst_rep) - ElementSizeLog2Of(smaller_rep));
+  int base = -1;
+  USE(base);
+  DCHECK_EQ(aliases, RegisterConfiguration::Default()->GetAliases(
+                         dst_rep, 0, smaller_rep, &base));
+
+  int src_index = -1;
+  int slot_size = (1 << ElementSizeLog2Of(smaller_rep)) / kSystemPointerSize;
+  int src_step = 1;
+  if (src_kind == LocationOperand::REGISTER) {
+    src_index = src_loc.register_code() * aliases;
+  } else {
+    src_index = src_loc.index();
+    // For operands that occupy multiple slots, the index refers to the last
+    // slot. On little-endian architectures, we start at the high slot and use a
+    // negative step so that register-to-slot moves are in the correct order.
+    src_step = -slot_size;
+  }
+  int dst_index = -1;
+  int dst_step = 1;
+  if (dst_kind == LocationOperand::REGISTER) {
+    dst_index = dst_loc.register_code() * aliases;
+  } else {
+    dst_index = dst_loc.index();
+    dst_step = -slot_size;
+  }
+
+  // Reuse 'move' for the first fragment. It is not pending.
+  move->set_source(AllocatedOperand(src_kind, smaller_rep, src_index));
+  move->set_destination(AllocatedOperand(dst_kind, smaller_rep, dst_index));
+  // Add the remaining fragment moves.
+  for (int i = 1; i < aliases; ++i) {
+    src_index += src_step;
+    dst_index += dst_step;
+    moves->AddMove(AllocatedOperand(src_kind, smaller_rep, src_index),
+                   AllocatedOperand(dst_kind, smaller_rep, dst_index));
+  }
+  // Return the first fragment.
+  return move;
+}
+
+enum MoveOperandKind : uint8_t { kConstant, kGpReg, kFpReg, kStack };
+
+MoveOperandKind GetKind(const InstructionOperand& move) {
+  if (move.IsConstant()) return kConstant;
+  LocationOperand loc_op = LocationOperand::cast(move);
+  if (loc_op.location_kind() != LocationOperand::REGISTER) return kStack;
+  return IsFloatingPoint(loc_op.representation()) ? kFpReg : kGpReg;
+}
+
+}  // namespace
+
+void GapResolver::Resolve(ParallelMove* moves) {
+  base::EnumSet<MoveOperandKind, uint8_t> source_kinds;
+  base::EnumSet<MoveOperandKind, uint8_t> destination_kinds;
+
+  // Remove redundant moves, collect source kinds and destination kinds to
+  // detect simple non-overlapping moves, and collect FP move representations if
+  // aliasing is non-simple.
+  int fp_reps = 0;
+  for (auto it = moves->begin(); it != moves->end();) {
+    MoveOperands* move = *it;
+    if (move->IsRedundant()) {
+      *it = moves->back();
+      moves->pop_back();
+      continue;
+    }
+    source_kinds.Add(GetKind(move->source()));
+    destination_kinds.Add(GetKind(move->destination()));
+    if (!kSimpleFPAliasing && move->destination().IsFPRegister()) {
+      fp_reps |= RepresentationBit(
+          LocationOperand::cast(move->destination()).representation());
+    }
+    ++it;
+  }
+
+  if ((source_kinds & destination_kinds).empty() || moves->size() < 2) {
+    // Fast path for non-conflicting parallel moves.
+    for (MoveOperands* move : *moves) {
+      assembler_->AssembleMove(&move->source(), &move->destination());
+    }
+    return;
+  }
+
+  if (!kSimpleFPAliasing) {
+    if (fp_reps && !base::bits::IsPowerOfTwo(fp_reps)) {
+      // Start with the smallest FP moves, so we never encounter smaller moves
+      // in the middle of a cycle of larger moves.
+      if ((fp_reps & RepresentationBit(MachineRepresentation::kFloat32)) != 0) {
+        split_rep_ = MachineRepresentation::kFloat32;
+        for (size_t i = 0; i < moves->size(); ++i) {
+          auto move = (*moves)[i];
+          if (!move->IsEliminated() && move->destination().IsFloatRegister())
+            PerformMove(moves, move);
+        }
+      }
+      if ((fp_reps & RepresentationBit(MachineRepresentation::kFloat64)) != 0) {
+        split_rep_ = MachineRepresentation::kFloat64;
+        for (size_t i = 0; i < moves->size(); ++i) {
+          auto move = (*moves)[i];
+          if (!move->IsEliminated() && move->destination().IsDoubleRegister())
+            PerformMove(moves, move);
+        }
+      }
+    }
+    split_rep_ = MachineRepresentation::kSimd128;
+  }
+
+  for (size_t i = 0; i < moves->size(); ++i) {
+    auto move = (*moves)[i];
+    if (!move->IsEliminated()) PerformMove(moves, move);
+  }
+}
+
+void GapResolver::PerformMove(ParallelMove* moves, MoveOperands* move) {
+  // Each call to this function performs a move and deletes it from the move
+  // graph.  We first recursively perform any move blocking this one.  We mark a
+  // move as "pending" on entry to PerformMove in order to detect cycles in the
+  // move graph.  We use operand swaps to resolve cycles, which means that a
+  // call to PerformMove could change any source operand in the move graph.
+  DCHECK(!move->IsPending());
+  DCHECK(!move->IsRedundant());
+
+  // Clear this move's destination to indicate a pending move.  The actual
+  // destination is saved on the side.
+  InstructionOperand source = move->source();
+  DCHECK(!source.IsInvalid());  // Or else it will look eliminated.
+  InstructionOperand destination = move->destination();
+  move->SetPending();
+
+  // We may need to split moves between FP locations differently.
+  const bool is_fp_loc_move =
+      !kSimpleFPAliasing && destination.IsFPLocationOperand();
+
+  // Perform a depth-first traversal of the move graph to resolve dependencies.
+  // Any unperformed, unpending move with a source the same as this one's
+  // destination blocks this one so recursively perform all such moves.
+  for (size_t i = 0; i < moves->size(); ++i) {
+    auto other = (*moves)[i];
+    if (other->IsEliminated()) continue;
+    if (other->IsPending()) continue;
+    if (other->source().InterferesWith(destination)) {
+      if (is_fp_loc_move &&
+          LocationOperand::cast(other->source()).representation() >
+              split_rep_) {
+        // 'other' must also be an FP location move. Break it into fragments
+        // of the same size as 'move'. 'other' is set to one of the fragments,
+        // and the rest are appended to 'moves'.
+        other = Split(other, split_rep_, moves);
+        // 'other' may not block destination now.
+        if (!other->source().InterferesWith(destination)) continue;
+      }
+      // Though PerformMove can change any source operand in the move graph,
+      // this call cannot create a blocking move via a swap (this loop does not
+      // miss any).  Assume there is a non-blocking move with source A and this
+      // move is blocked on source B and there is a swap of A and B.  Then A and
+      // B must be involved in the same cycle (or they would not be swapped).
+      // Since this move's destination is B and there is only a single incoming
+      // edge to an operand, this move must also be involved in the same cycle.
+      // In that case, the blocking move will be created but will be "pending"
+      // when we return from PerformMove.
+      PerformMove(moves, other);
+    }
+  }
+
+  // This move's source may have changed due to swaps to resolve cycles and so
+  // it may now be the last move in the cycle.  If so remove it.
+  source = move->source();
+  if (source.EqualsCanonicalized(destination)) {
+    move->Eliminate();
+    return;
+  }
+
+  // We are about to resolve this move and don't need it marked as pending, so
+  // restore its destination.
+  move->set_destination(destination);
+
+  // The move may be blocked on a (at most one) pending move, in which case we
+  // have a cycle.  Search for such a blocking move and perform a swap to
+  // resolve it.
+  auto blocker =
+      std::find_if(moves->begin(), moves->end(), [&](MoveOperands* move) {
+        return !move->IsEliminated() &&
+               move->source().InterferesWith(destination);
+      });
+  if (blocker == moves->end()) {
+    // The easy case: This move is not blocked.
+    assembler_->AssembleMove(&source, &destination);
+    move->Eliminate();
+    return;
+  }
+
+  // Ensure source is a register or both are stack slots, to limit swap cases.
+  if (source.IsStackSlot() || source.IsFPStackSlot()) {
+    std::swap(source, destination);
+  }
+  assembler_->AssembleSwap(&source, &destination);
+  move->Eliminate();
+
+  // Update outstanding moves whose source may now have been moved.
+  if (is_fp_loc_move) {
+    // We may have to split larger moves.
+    for (size_t i = 0; i < moves->size(); ++i) {
+      auto other = (*moves)[i];
+      if (other->IsEliminated()) continue;
+      if (source.InterferesWith(other->source())) {
+        if (LocationOperand::cast(other->source()).representation() >
+            split_rep_) {
+          other = Split(other, split_rep_, moves);
+          if (!source.InterferesWith(other->source())) continue;
+        }
+        other->set_source(destination);
+      } else if (destination.InterferesWith(other->source())) {
+        if (LocationOperand::cast(other->source()).representation() >
+            split_rep_) {
+          other = Split(other, split_rep_, moves);
+          if (!destination.InterferesWith(other->source())) continue;
+        }
+        other->set_source(source);
+      }
+    }
+  } else {
+    for (auto other : *moves) {
+      if (other->IsEliminated()) continue;
+      if (source.EqualsCanonicalized(other->source())) {
+        other->set_source(destination);
+      } else if (destination.EqualsCanonicalized(other->source())) {
+        other->set_source(source);
+      }
+    }
+  }
+}
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8