Allow smi comparisons to have constant operands.

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 637 matching lines @@
 
   // Record the corresponding phi input use for each phi.
   ZoneGrowableArray<PhiInstr*>* phis = join->phis();
   intptr_t move_idx = 0;
   for (intptr_t phi_idx = 0; phi_idx < phis->length(); phi_idx++) {
     PhiInstr* phi = (*phis)[phi_idx];
     if (phi == NULL) continue;
 
     Value* val = phi->InputAt(pred_idx);
     MoveOperands* move = parallel_move->MoveOperandsAt(move_idx);
+
+    ConstantInstr* constant = val->definition()->AsConstant();
+    if (constant != NULL) {
+      move->set_src(Location::Constant(constant->value()));
+      move_idx++;
+      continue;
+    }
+
     // Expected shape of live ranges:
     //
     //                 g  g'
     //      value    --*
     //
 
     LiveRange* range = GetLiveRange(val->definition()->ssa_temp_index());
 
     range->AddUseInterval(block->start_pos(), pos);
     range->AddHintedUse(pos, move->src_slot(), move->dest_slot());
@@ skipping 1507 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart