Generalize if-conversion to arbitrary smi comparisons.

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/block_scheduler.h"
@@ skipping 352 matching lines @@
 
         // Propagate types and eliminate more type tests.
         FlowGraphTypePropagator::Propagate(flow_graph);
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         // Use propagated class-ids to optimize further.
         optimizer.ApplyClassIds();
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         // Do optimizations that depend on the propagated type information.
-        optimizer.Canonicalize();
+        if (optimizer.Canonicalize()) {
+          // Invoke Canonicalize twice in order to fully canonicalize certains

[Kevin Millikin (Google), 2013/11/22 14:09:34]

certains ==> certain, or just get rid of it because it's a noise word.

+          // patterns like "if (a & const == 0) { }".
+          optimizer.Canonicalize();
+        }
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         BranchSimplifier::Simplify(flow_graph);
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         IfConverter::Simplify(flow_graph);
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         if (FLAG_constant_propagation) {
           ConstantPropagator::Optimize(flow_graph);
@@ skipping 544 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