Fix several register allocation issues revealed by fuzzer:

- LIsObject had incorrect contraint for value input;
- Temporaries had incorrect lifetime intervals;
- Live ranges for live_out values was not covering the whole block.

Review URL: http://codereview.chromium.org/5899002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6038 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ia32/lithium-ia32.cc

@@ -1650,7 +1650,7 @@ LInstruction* LChunkBuilder::DoIsNull(HIsNull* instr) {
 
 LInstruction* LChunkBuilder::DoIsObject(HIsObject* instr) {
   ASSERT(instr->value()->representation().IsTagged());
-  LOperand* value = UseRegisterAtStart(instr->value());
+  LOperand* value = UseRegister(instr->value());
 
   return DefineAsRegister(new LIsObject(value, TempRegister()));
 }

src/lithium-allocator.cc

@@ -585,17 +585,12 @@ void LAllocator::AddInitialIntervals(HBasicBlock* block,
   LifetimePosition start = LifetimePosition::FromInstructionIndex(
       block->first_instruction_index());
   LifetimePosition end = LifetimePosition::FromInstructionIndex(
-      block->last_instruction_index());
+      block->last_instruction_index()).NextInstruction();
   BitVector::Iterator iterator(live_out);
   while (!iterator.Done()) {
     int operand_index = iterator.Current();
     LiveRange* range = LiveRangeFor(operand_index);
-    if (!range->IsEmpty() &&
-        range->Start().Value() == end.NextInstruction().Value()) {
-      range->AddUseInterval(start, end.NextInstruction());
-    } else {
-      range->AddUseInterval(start, end);
-    }
+    range->AddUseInterval(start, end);
     iterator.Advance();
   }
 }
@@ -978,8 +973,8 @@ void LAllocator::ProcessInstructions(HBasicBlock* block, BitVector* live) {
               }
             }
           }
-          Use(block_start_position, curr_position, temp, NULL);
-          Define(curr_position.PrevInstruction(), temp, NULL);
+          Use(block_start_position, curr_position.InstructionEnd(), temp, NULL);
+          Define(curr_position, temp, NULL);
         }
       }
     }
@@ -1832,7 +1827,7 @@ bool LAllocator::TryAllocateFreeReg(LiveRange* current) {
   // Register reg is available at the range start and is free until
   // the range end.
   ASSERT(pos.Value() >= current->End().Value());
-  TraceAlloc("Assigning reg %s to live range %d\n",
+  TraceAlloc("Assigning free reg %s to live range %d\n",
              RegisterName(reg),
              current->id());
   current->set_assigned_register(reg, mode_);
@@ -1922,7 +1917,7 @@ void LAllocator::AllocateBlockedReg(LiveRange* current) {
 
   // Register reg is not blocked for the whole range.
   ASSERT(block_pos[reg].Value() >= current->End().Value());
-  TraceAlloc("Assigning reg %s to live range %d\n",
+  TraceAlloc("Assigning blocked reg %s to live range %d\n",
              RegisterName(reg),
              current->id());
   current->set_assigned_register(reg, mode_);

test/mjsunit/fuzz-natives.js

@@ -25,7 +25,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --allow-natives-syntax --noalways-opt
+// Flags: --allow-natives-syntax
 
 var RUN_WITH_ALL_ARGUMENT_ENTRIES = false;
 var kOnManyArgumentsRemove = 5;