Fix a bug in the liveness analysis.

A range after a loop might also be after a lifetime hole.
In this situation we must preserve the hole, and not merge
it with the loop start.

Change-Id: I82eddef059592102a25362cdaa4273200574c2ae

1 files changed, 51 insertions, 0 deletions

diff --git a/compiler/optimizing/live_interval_test.cc b/compiler/optimizing/live_interval_test.cc
index 3e4b83b0b1..ac8759c805 100644
--- a/compiler/optimizing/live_interval_test.cc
+++ b/compiler/optimizing/live_interval_test.cc
@@ -278,4 +278,55 @@ TEST(LiveInterval, SplitAt) {
   }
 }
 
+TEST(LiveInterval, AddLoopRange) {
+  ArenaPool pool;
+  ArenaAllocator allocator(&pool);
+
+  {
+    // Test when only used in a loop.
+    static constexpr size_t ranges[][2] = {{0, 4}};
+    LiveInterval* interval = BuildInterval(ranges, arraysize(ranges), &allocator);
+    interval->AddLoopRange(0, 8);
+    LiveRange* range = interval->GetFirstRange();
+    ASSERT_TRUE(range->GetNext() == nullptr);
+    ASSERT_EQ(range->GetStart(), 0u);
+    ASSERT_EQ(range->GetEnd(), 8u);
+  }
+
+  {
+    // Test when only used in a loop.
+    static constexpr size_t ranges[][2] = {{2, 4}};
+    LiveInterval* interval = BuildInterval(ranges, arraysize(ranges), &allocator);
+    interval->AddLoopRange(0, 8);
+    LiveRange* range = interval->GetFirstRange();
+    ASSERT_TRUE(range->GetNext() == nullptr);
+    ASSERT_EQ(range->GetStart(), 0u);
+    ASSERT_EQ(range->GetEnd(), 8u);
+  }
+
+  {
+    // Test when used just after the loop.
+    static constexpr size_t ranges[][2] = {{2, 4}, {8, 10}};
+    LiveInterval* interval = BuildInterval(ranges, arraysize(ranges), &allocator);
+    interval->AddLoopRange(0, 8);
+    LiveRange* range = interval->GetFirstRange();
+    ASSERT_TRUE(range->GetNext() == nullptr);
+    ASSERT_EQ(range->GetStart(), 0u);
+    ASSERT_EQ(range->GetEnd(), 10u);
+  }
+
+  {
+    // Test when use after the loop is after a lifetime hole.
+    static constexpr size_t ranges[][2] = {{2, 4}, {10, 12}};
+    LiveInterval* interval = BuildInterval(ranges, arraysize(ranges), &allocator);
+    interval->AddLoopRange(0, 8);
+    LiveRange* range = interval->GetFirstRange();
+    ASSERT_EQ(range->GetStart(), 0u);
+    ASSERT_EQ(range->GetEnd(), 8u);
+    range = range->GetNext();
+    ASSERT_EQ(range->GetStart(), 10u);
+    ASSERT_EQ(range->GetEnd(), 12u);
+  }
+}
+
 }  // namespace art