Remove unnecessary recording of temp operands in the register allocator.

When processing register contraints we used to add writable input operands
also as temp operands to the same instruction.

This does not seem necessary since we create a fresh virtual register
for writable inputs and insert a definition in the gap before the instruction.

Review URL: http://codereview.chromium.org/6350002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6342 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/lithium-allocator.cc

@@ -828,6 +828,10 @@ void LAllocator::MeetConstraintsBetween(InstructionSummary* first,
         AllocateFixed(cur_input, gap_index + 1, is_tagged);
         AddConstraintsGapMove(gap_index, input_copy, cur_input);
       } else if (cur_input->policy() == LUnallocated::WRITABLE_REGISTER) {
+        // The live range of writable input registers always goes until the end
+        // of the instruction.
+        ASSERT(!cur_input->IsUsedAtStart());
+
         LUnallocated* input_copy = cur_input->CopyUnconstrained();
         cur_input->set_virtual_register(next_virtual_register_++);
 
@@ -837,7 +841,6 @@ void LAllocator::MeetConstraintsBetween(InstructionSummary* first,
               cur_input->virtual_register() - first_artificial_register_);
         }
 
-        second->AddTemp(cur_input);
         AddConstraintsGapMove(gap_index, input_copy, cur_input);
       }
     }