[turbofan] Single entry into deferred regions

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/bit-vector.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/register-allocator-verifier.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 264 matching lines @@
   if (moves == nullptr) return;
 
   CHECK(map_for_moves_.empty());
   for (MoveOperands* move : *moves) {
     if (move->IsEliminated() || move->IsRedundant()) continue;
     auto it = map_.find(move->source());
     // The RHS of a parallel move should have been already assessed.
     CHECK(it != map_.end());
     // The LHS of a parallel move should not have been assigned in this
     // parallel move.
-    // TODO(mtrofin): this check fails when generating code for
-    // CodeStubAssembler::ChangeUint32ToTagged.
-    // CHECK(map_for_moves_.find(move->destination()) ==  map_for_moves_.end());
+    CHECK(map_for_moves_.find(move->destination()) == map_for_moves_.end());
     // Copy the assessment to the destination.
     map_for_moves_[move->destination()] = it->second;
   }
   for (auto pair : map_for_moves_) {
     map_[pair.first] = pair.second;
   }
   map_for_moves_.clear();
 }
 
 void BlockAssessments::DropRegisters() {
@@ skipping 113 matching lines @@
 
       switch (contribution->kind()) {
         case Final:
           ValidateFinalAssessment(
               block_id, current_operand, current_assessments,
               FinalAssessment::cast(contribution), expected);
           break;
         case Pending: {
           // This happens if we have a diamond feeding into another one, and
           // the inner one never being used - other than for carrying the value.
-          PendingAssessment* next = PendingAssessment::cast(contribution);
+          const PendingAssessment* next = PendingAssessment::cast(contribution);
           if (seen.find(pred) == seen.end()) {
             worklist.push({next, expected});
             seen.insert(pred);
           }
           // Note that we do not want to finalize pending assessments at the
           // beginning of a block - which is the information we'd have
           // available here. This is because this operand may be reused to
           // define
           // duplicate phis.
           break;
@@ skipping 121 matching lines @@
               new (zone()) FinalAssessment(vreg, pending);
           break;
       }
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8