Fix control flow resolution bug in lithium register allocator.

src/lithium-allocator.cc

Index: src/lithium-allocator.cc
diff --git a/src/lithium-allocator.cc b/src/lithium-allocator.cc
index cac7d65e98f0dc4c91fd387236a647e954e95f40..81877f37685a01fad0cfd4e6a2c399121a41e1eb 100644
--- a/src/lithium-allocator.cc
+++ b/src/lithium-allocator.cc
@@ -1068,9 +1068,7 @@ void LAllocator::ResolveControlFlow(LiveRange* range,
                                     HBasicBlock* block,
                                     HBasicBlock* pred) {
   LifetimePosition pred_end =
-      LifetimePosition::FromInstructionIndex(pred->last_instruction_index()).
-      PrevInstruction();
-
+      LifetimePosition::FromInstructionIndex(pred->last_instruction_index());
   LifetimePosition cur_start =
       LifetimePosition::FromInstructionIndex(block->first_instruction_index());
   LiveRange* pred_cover = NULL;
@@ -1245,7 +1243,7 @@ void LAllocator::BuildLiveRanges() {
       LifetimePosition start = LifetimePosition::FromInstructionIndex(
           block->first_instruction_index());
       LifetimePosition end = LifetimePosition::FromInstructionIndex(
-          back_edge->last_instruction_index());
+          back_edge->last_instruction_index()).NextInstruction();
       while (!iterator.Done()) {
         int operand_index = iterator.Current();
         LiveRange* range = LiveRangeFor(operand_index);
@@ -2019,6 +2017,11 @@ LiveRange* LAllocator::SplitAt(LiveRange* range, LifetimePosition pos) {
 
   if (pos.Value() <= range->Start().Value()) return range;
 
+  // We can't properly connect liveranges if split occured at the end
+  // of control instruction.
+  ASSERT(pos.IsInstructionStart() ||
+         !chunk_->instructions()->at(pos.InstructionIndex())->IsControl());
+
   LiveRange* result = LiveRangeFor(next_virtual_register_++);
   range->SplitAt(pos, result);
   return result;