[turbofan] Live Range unit tests.

Unit tests for split/splinter/merge.

BUG=

Review URL: https://codereview.chromium.org/1315113003

Cr-Commit-Position: refs/heads/master@{#30475}

src/compiler/register-allocator.cc

@@ -437,6 +437,7 @@ LiveRange* LiveRange::SplitAt(LifetimePosition position, Zone* zone) {
 void LiveRange::DetachAt(LifetimePosition position, LiveRange* result,
                          Zone* zone) {
   DCHECK(Start() < position);
+  DCHECK(End() > position);
   DCHECK(result->IsEmpty());
   // Find the last interval that ends before the position. If the
   // position is contained in one of the intervals in the chain, we
@@ -878,7 +879,7 @@ void TopLevelLiveRange::SetSplinteredFrom(TopLevelLiveRange* splinter_parent) {
   DCHECK(splinter_parent->Start() < Start());
 
   splintered_from_ = splinter_parent;
-  if (!HasSpillOperand()) {
+  if (!HasSpillOperand() && splinter_parent->spill_range_ != nullptr) {
     SetSpillRange(splinter_parent->spill_range_);
   }
 }

test/unittests/compiler/live-range-builder.h

@@ -17,7 +17,8 @@ namespace compiler {
 // support for C++ features such as instantiation lists, on OS X and Android.
 class TestRangeBuilder {
  public:
-  explicit TestRangeBuilder(Zone* zone) : id_(-1), pairs_(), zone_(zone) {}
+  explicit TestRangeBuilder(Zone* zone)
+      : id_(-1), pairs_(), uses_(), zone_(zone) {}
 
   TestRangeBuilder& Id(int id) {
     id_ = id;
@@ -28,9 +29,16 @@ class TestRangeBuilder {
     return *this;
   }
 
-  LiveRange* Build(int start, int end) { return Add(start, end).Build(); }
+  TestRangeBuilder& AddUse(int pos) {
+    uses_.insert(pos);
+    return *this;
+  }
 
-  LiveRange* Build() {
+  TopLevelLiveRange* Build(int start, int end) {
+    return Add(start, end).Build();
+  }
+
+  TopLevelLiveRange* Build() {
     TopLevelLiveRange* range =
         new (zone_) TopLevelLiveRange(id_, MachineType::kRepTagged);
     // Traverse the provided interval specifications backwards, because that is
@@ -42,6 +50,12 @@ class TestRangeBuilder {
       CHECK(start < end);
       range->AddUseInterval(start, end, zone_);
     }
+    for (int pos : uses_) {
+      UsePosition* use_position =
+          new (zone_) UsePosition(LifetimePosition::FromInt(pos), nullptr,
+                                  nullptr, UsePositionHintType::kNone);
+      range->AddUsePosition(use_position);
+    }
 
     pairs_.clear();
     return range;
@@ -52,6 +66,7 @@ class TestRangeBuilder {
   typedef std::vector<Interval> IntervalList;
   int id_;
   IntervalList pairs_;
+  std::set<int> uses_;
   Zone* zone_;
 };
 

test/unittests/unittests.gyp

@@ -70,6 +70,7 @@
         'compiler/js-type-feedback-unittest.cc',
         'compiler/linkage-tail-call-unittest.cc',
         'compiler/liveness-analyzer-unittest.cc',
+        'compiler/live-range-unittest.cc',
         'compiler/load-elimination-unittest.cc',
         'compiler/loop-peeling-unittest.cc',
         'compiler/machine-operator-reducer-unittest.cc',