Revert "Change the SSA construction pass to also construct def-use chains."

runtime/vm/compiler.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/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/code_generator.h"
@@ skipping 141 matching lines @@
       FlowGraphBuilder builder(parsed_function, NULL);  // NULL = not inlining.
       flow_graph = builder.BuildGraph();
     }
 
     if (optimized) {
       TimerScope timer(FLAG_compiler_stats,
                        &CompilerStats::ssa_timer,
                        isolate);
       // Transform to SSA (virtual register 0 and no inlining arguments).
       flow_graph->ComputeSSA(0, NULL);
-      DEBUG_ASSERT(flow_graph->VerifyUseLists());
+      flow_graph->ComputeUseLists();
     }
 
     if (FLAG_print_flow_graph ||
         (optimized && FLAG_print_flow_graph_optimized)) {
       OS::Print("Before Optimizations\n");
       FlowGraphPrinter printer(*flow_graph);
       printer.PrintBlocks();
     }
 
     if (optimized) {
@@ skipping 469 matching lines @@
       Object::Handle(isolate->object_store()->sticky_error());
     isolate->object_store()->clear_sticky_error();
     isolate->set_long_jump_base(base);
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart