[turbofan] remove one level of indirection in phi inputs

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/compiler/pipeline.h"
 #include "test/unittests/compiler/instruction-sequence-unittest.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 24 matching lines @@
   // i = K;
   // while(true) { i++ }
   StartBlock();
   auto i_reg = DefineConstant();
   EndBlock();
 
   {
     StartLoop(1);
 
     StartBlock();
-    auto phi = Phi(i_reg);
+    auto phi = Phi(i_reg, 2);
     auto ipp = EmitOI(Same(), Reg(phi), Use(DefineConstant()));
-    Extend(phi, ipp);
+    SetInput(phi, 1, ipp);
     EndBlock(Jump(0));
 
     EndLoop();
   }
 
   Allocate();
 }
 
 
 TEST_F(RegisterAllocatorTest, SimpleBranch) {
@@ skipping 141 matching lines @@
   EndBlock();
 
   PhiInstruction* phis[kParams];
   {
     StartLoop(2);
 
     // Loop header.
     StartBlock();
 
     for (size_t i = 0; i < arraysize(parameters); ++i) {
-      phis[i] = Phi(parameters[i]);
+      phis[i] = Phi(parameters[i], 2);
     }
 
     // Perform some computations.
     // something like phi[i] += const
     for (size_t i = 0; i < arraysize(parameters); ++i) {
       auto result = EmitOI(Same(), Reg(phis[i]), Use(constant));
-      Extend(phis[i], result);
+      SetInput(phis[i], 1, result);
     }
 
     EndBlock(Branch(Reg(DefineConstant()), 1, 2));
 
     // Jump back to loop header.
     StartBlock();
     EndBlock(Jump(-1));
 
     EndLoop();
   }
@@ skipping 235 matching lines @@
   EmitI(Reg(c));
   EmitI(Reg(to_spill));
   EndBlock(Last());
 
   Allocate();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8