[turbofan] relative_id of splinters and their children.

test/unittests/compiler/live-range-unittest.cc

 // Copyright 2015 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 "test/unittests/compiler/live-range-builder.h"
 #include "test/unittests/test-utils.h"
 
 
 // TODO(mtrofin): would we want to centralize this definition?
@@ skipping 389 matching lines @@
   TopLevelLiveRange* result = TestRangeBuilder(zone()).Build(0, 8);
   LiveRange* child_1 = Split(result, 2);
   LiveRange* child_2 = Split(child_1, 4);
   LiveRange* child_3 = Split(child_2, 6);
   Split(child_3, 7);
 
   EXPECT_TRUE(RangesMatch(result, original));
 }
 
 
+TEST_F(LiveRangeUnitTest, IDGeneration) {
+  TopLevelLiveRange* vreg = TestRangeBuilder(zone()).Id(2).Build(0, 100);
+  EXPECT_EQ(2, vreg->vreg());
+  EXPECT_EQ(0, vreg->relative_id());
+
+  TopLevelLiveRange* splinter =
+      new (zone()) TopLevelLiveRange(101, MachineType::kRepTagged);
+  vreg->Splinter(LifetimePosition::FromInt(4), LifetimePosition::FromInt(12),
+                 splinter, zone());
+
+  EXPECT_EQ(101, splinter->vreg());
+  EXPECT_EQ(1, splinter->relative_id());
+
+  LiveRange* child = vreg->SplitAt(LifetimePosition::FromInt(50), zone());
+
+  EXPECT_EQ(2, child->relative_id());
+
+  LiveRange* splinter_child =
+      splinter->SplitAt(LifetimePosition::FromInt(8), zone());
+
+  EXPECT_EQ(1, splinter->relative_id());
+  EXPECT_EQ(3, splinter_child->relative_id());
+
+  vreg->Merge(splinter, zone());
+  EXPECT_EQ(1, splinter->relative_id());
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8