[turbofan] Regalloc validator: support same block pending assessment

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 452 matching lines @@
   if (assessment->virtual_register() == virtual_register) return;
   // If we have 2 phis with the exact same operand list, and the first phi is
   // used before the second one, via the operand incoming to the block,
   // and the second one's operand is defined (via a parallel move) after the
   // use, then the original operand will be assigned to the first phi. We
   // then look at the original pending assessment to ascertain if op
   // is virtual_register.
   const PendingAssessment* old = assessment->original_pending_assessment();
   CHECK_NOT_NULL(old);
   RpoNumber old_block = old->origin()->rpo_number();
-  BlockAssessments* old_block_assessments = assessments_[old_block];
+  DCHECK_LE(old_block, block_id);
+  BlockAssessments* old_block_assessments =
+      old_block == block_id ? current_assessments : assessments_[old_block];
   ValidatePendingAssessment(old_block, op, old_block_assessments, old,
                             virtual_register);
 }
 
 void RegisterAllocatorVerifier::ValidateUse(
     RpoNumber block_id, BlockAssessments* current_assessments,
     InstructionOperand op, int virtual_register) {
   auto iterator = current_assessments->map().find(op);
   // We should have seen this operand before.
   CHECK(iterator != current_assessments->map().end());
@@ skipping 89 matching lines @@
               new (zone()) FinalAssessment(vreg, pending);
           break;
       }
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8