[turbofan] Support virtual register redirection in instruction selector.

test/unittests/compiler/instruction-selector-unittest.cc

Index: test/unittests/compiler/instruction-selector-unittest.cc
diff --git a/test/unittests/compiler/instruction-selector-unittest.cc b/test/unittests/compiler/instruction-selector-unittest.cc
index d0e3bd08e1e3bef3094a05c1800238ad0e4a1514..18ccaaaea5acc70f6c4acac88f4647e4f75bbfef 100644
--- a/test/unittests/compiler/instruction-selector-unittest.cc
+++ b/test/unittests/compiler/instruction-selector-unittest.cc
@@ -245,19 +245,13 @@ TARGET_TEST_F(InstructionSelectorTest, FinishRegion) {
       m.AddNode(m.common()->FinishRegion(), param, m.graph()->start());
   m.Return(finish);
   Stream s = m.Build(kAllInstructions);
-  ASSERT_EQ(4U, s.size());
+  ASSERT_EQ(3U, s.size());
   EXPECT_EQ(kArchNop, s[0]->arch_opcode());
   ASSERT_EQ(1U, s[0]->OutputCount());
   ASSERT_TRUE(s[0]->Output()->IsUnallocated());
+  EXPECT_EQ(kArchRet, s[1]->arch_opcode());
   EXPECT_EQ(s.ToVreg(param), s.ToVreg(s[0]->Output()));
-  EXPECT_EQ(kArchNop, s[1]->arch_opcode());
-  ASSERT_EQ(1U, s[1]->InputCount());
-  ASSERT_TRUE(s[1]->InputAt(0)->IsUnallocated());
   EXPECT_EQ(s.ToVreg(param), s.ToVreg(s[1]->InputAt(0)));
-  ASSERT_EQ(1U, s[1]->OutputCount());
-  ASSERT_TRUE(s[1]->Output()->IsUnallocated());
-  EXPECT_TRUE(UnallocatedOperand::cast(s[1]->Output())->HasSameAsInputPolicy());
-  EXPECT_EQ(s.ToVreg(finish), s.ToVreg(s[1]->Output()));
   EXPECT_TRUE(s.IsReference(finish));
 }