Disregard constants with no SSA temp index in register allocator.

runtime/vm/flow_graph_allocator.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_allocator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/intermediate_language.h"
 #include "vm/il_printer.h"
 #include "vm/flow_graph.h"
@@ skipping 769 matching lines @@
 
 // Create and update live ranges corresponding to instruction's inputs,
 // temporaries and output.
 void FlowGraphAllocator::ProcessOneInstruction(BlockEntryInstr* block,
                                                Instruction* current) {
   LocationSummary* locs = current->locs();
 
   Definition* def = current->AsDefinition();
   if ((def != NULL) &&
       (def->AsConstant() != NULL) &&
-      (GetLiveRange(def->ssa_temp_index())->first_use() == NULL)) {
+      ((def->ssa_temp_index() == -1) ||
+       (GetLiveRange(def->ssa_temp_index())->first_use() == NULL))) {
     // Drop definitions of constants that have no uses.
     locs->set_out(Location::NoLocation());
     return;
   }
 
   const intptr_t pos = current->lifetime_position();
   ASSERT(IsInstructionStartPosition(pos));
 
   // Number of input locations and number of input operands have to agree.
   ASSERT(locs->input_count() == current->InputCount());
@@ skipping 1403 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart