[turbofan] Get rid of SourcePositionInstruction.

src/compiler/move-optimizer.cc

 // 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/move-optimizer.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 namespace {
 
 typedef std::pair<InstructionOperand, InstructionOperand> MoveKey;
 typedef ZoneMap<MoveKey, unsigned> MoveMap;
 typedef ZoneSet<InstructionOperand> OperandSet;
 
 
-bool GapsCanMoveOver(Instruction* instr) {
-  return instr->IsSourcePosition() || instr->IsNop();
-}
+bool GapsCanMoveOver(Instruction* instr) { return instr->IsNop(); }
 
 
 int FindFirstNonEmptySlot(Instruction* instr) {
   int i = Instruction::FIRST_GAP_POSITION;
   for (; i <= Instruction::LAST_GAP_POSITION; i++) {
     auto move = instr->parallel_moves()[i];
     if (move == nullptr) continue;
     auto move_ops = move->move_operands();
     auto op = move_ops->begin();
     for (; op != move_ops->end(); ++op) {
@@ skipping 107 matching lines @@
 }
 
 
 void MoveOptimizer::OptimizeMerge(InstructionBlock* block) {
   DCHECK(block->PredecessorCount() > 1);
   // Ensure that the last instruction in all incoming blocks don't contain
   // things that would prevent moving gap moves across them.
   for (auto pred_index : block->predecessors()) {
     auto pred = code()->InstructionBlockAt(pred_index);
     auto last_instr = code()->instructions()[pred->last_instruction_index()];
-    if (last_instr->IsSourcePosition()) continue;
     if (last_instr->IsCall()) return;
     if (last_instr->TempCount() != 0) return;
     if (last_instr->OutputCount() != 0) return;
     for (size_t i = 0; i < last_instr->InputCount(); ++i) {
       auto op = last_instr->InputAt(i);
       if (!op->IsConstant() && !op->IsImmediate()) return;
     }
   }
   // TODO(dcarney): pass a ZonePool down for this?
   MoveMap move_map(local_zone());
@@ skipping 130 matching lines @@
     std::swap(*new_move, *it);
     ++it;
   }
   DCHECK_EQ(it, slot_1->move_operands()->end());
   new_moves.clear();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8