[turbofan]: delay ssa deconstruction in register allocator

test/unittests/compiler/register-allocator-unittest.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/base/utils/random-number-generator.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/pipeline.h"
 #include "test/unittests/test-utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
@@ skipping 225 matching lines @@
 
   int Return(TestOperand input_op_0) {
     block_returns_ = true;
     InstructionOperand* inputs[1]{ConvertInputOp(input_op_0)};
     return Emit(NewIndex(), kArchRet, 0, nullptr, 1, inputs);
   }
 
   int Return(VReg vreg) { return Return(Reg(vreg, 0)); }
 
   PhiInstruction* Phi(VReg incoming_vreg) {
-    PhiInstruction* phi = new (zone()) PhiInstruction(zone(), NewReg().value_);
-    phi->operands().push_back(incoming_vreg.value_);
+    PhiInstruction* phi =
+        new (zone()) PhiInstruction(zone(), NewReg().value_, 10);
+    phi->Extend(zone(), incoming_vreg.value_);
     current_block_->AddPhi(phi);
     return phi;
   }
 
   PhiInstruction* Phi(VReg incoming_vreg_0, VReg incoming_vreg_1) {
     auto phi = Phi(incoming_vreg_0);
     Extend(phi, incoming_vreg_1);
     return phi;
   }
 
-  static void Extend(PhiInstruction* phi, VReg vreg) {
-    phi->operands().push_back(vreg.value_);
+  void Extend(PhiInstruction* phi, VReg vreg) {
+    phi->Extend(zone(), vreg.value_);
   }
 
   VReg DefineConstant(int32_t imm = 0) {
     VReg vreg = NewReg();
     sequence()->AddConstant(vreg.value_, Constant(imm));
     InstructionOperand* outputs[1]{
         ConstantOperand::Create(vreg.value_, zone())};
     Emit(vreg.value_, kArchNop, 1, outputs);
     return vreg;
   }
@@ skipping 454 matching lines @@
   StartBlock();
   Return(DefineConstant());
   EndBlock();
 
   Allocate();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8