Fix control flow resolution bug in lithium register allocator.

src/lithium-allocator.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1050 matching lines @@
     HBasicBlock* block = blocks->at(block_id);
     ResolvePhis(block);
   }
 }
 
 
 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;
   LiveRange* cur_cover = NULL;
   LiveRange* cur_range = range;
   while (cur_range != NULL && (cur_cover == NULL || pred_cover == NULL)) {
     if (cur_range->CanCover(cur_start)) {
       ASSERT(cur_cover == NULL);
       cur_cover = cur_range;
     }
@@ skipping 154 matching lines @@
     if (block->IsLoopHeader()) {
       // TODO(kmillikin): Need to be able to get the last block of the loop
       // in the loop information. Add a live range stretching from the first
       // loop instruction to the last for each value live on entry to the
       // header.
       HBasicBlock* back_edge = block->loop_information()->GetLastBackEdge();
       BitVector::Iterator iterator(live);
       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);
         range->EnsureInterval(start, end);
         iterator.Advance();
       }
 
       for (int i = block->block_id() + 1; i <= back_edge->block_id(); ++i) {
         live_in_sets_[i]->Union(*live);
       }
@@ skipping 753 matching lines @@
       chunk_->instructions()->at(pos.InstructionIndex())->IsLabel();
 }
 
 
 LiveRange* LAllocator::SplitAt(LiveRange* range, LifetimePosition pos) {
   ASSERT(!range->IsFixed());
   TraceAlloc("Splitting live range %d at %d\n", range->id(), pos.Value());
 
   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;
 }
 
 
 LiveRange* LAllocator::SplitBetween(LiveRange* range,
                                     LifetimePosition start,
                                     LifetimePosition end) {
   ASSERT(!range->IsFixed());
@@ skipping 100 matching lines @@
     LiveRange* current = live_ranges()->at(i);
     if (current != NULL) current->Verify();
   }
 }
 
 
 #endif
 
 
 } }  // namespace v8::internal