[turbofan]: delay ssa deconstruction in register allocator

src/compiler/register-allocator-verifier.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/instruction.h"
 #include "src/compiler/register-allocator-verifier.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 226 matching lines @@
                                   LocationMap::allocator_type(zone)) {}
 
   LocationMap* locations() { return &locations_; }
 
   void RunPhis(const InstructionSequence* sequence,
                const InstructionBlock* block, size_t phi_index) {
     // This operation is only valid in edge split form.
     size_t predecessor_index = block->predecessors()[phi_index].ToSize();
     CHECK(sequence->instruction_blocks()[predecessor_index]->SuccessorCount() ==
           1);
-    const auto* gap = sequence->GetBlockStart(block->rpo_number());
-    // The first moves in the BlockStartInstruction are the phi moves inserted
-    // by ResolvePhis.
-    const ParallelMove* move = gap->GetParallelMove(GapInstruction::START);
-    CHECK_NE(nullptr, move);
-    const auto* move_ops = move->move_operands();
-    CHECK(block->phis().size() <= static_cast<size_t>(move_ops->length()));
-    auto move_it = move_ops->begin();
     for (const auto* phi : block->phis()) {
-      const auto* op = move_it->source();
-      auto it = locations()->find(op);
+      auto input = phi->inputs()[phi_index];
+      CHECK(locations()->find(input) != locations()->end());
+      auto it = locations()->find(phi->output());
       CHECK(it != locations()->end());
-      CHECK_EQ(it->second, phi->operands()[phi_index]);
+      if (input->IsConstant()) {
+        CHECK_EQ(it->second, input->index());
+      } else {
+        CHECK_EQ(it->second, phi->operands()[phi_index]);
+      }
       it->second = phi->virtual_register();
-      ++move_it;
     }
   }
 
   void RunGapInstruction(Zone* zone, const GapInstruction* gap) {
     for (int i = GapInstruction::FIRST_INNER_POSITION;
          i <= GapInstruction::LAST_INNER_POSITION; i++) {
       GapInstruction::InnerPosition inner_pos =
           static_cast<GapInstruction::InnerPosition>(i);
       const ParallelMove* move = gap->GetParallelMove(inner_pos);
       if (move == nullptr) continue;
@@ skipping 185 matching lines @@
         const auto* gap = GapInstruction::cast(instr);
         current->RunGapInstruction(zone(), gap);
       }
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8