Take representation into account in ConstantPropagator::VisitInstanceOfInstr

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2013, 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_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 6306 matching lines @@
   if (IsNonConstant(value)) {
     SetValue(instr, non_constant_);
   } else if (IsConstant(value)) {
     bool val = value.raw() != Bool::True().raw();
     SetValue(instr, Bool::Get(val));
   }
 }
 
 
 void ConstantPropagator::VisitInstanceOf(InstanceOfInstr* instr) {
-  const Object& value = instr->value()->definition()->constant_value();
+  const Definition* def = instr->value()->definition();
+  const Object& value = def->constant_value();
   if (IsNonConstant(value)) {
-    SetValue(instr, non_constant_);
+    const AbstractType& checked_type = instr->type();
+    Representation rep = def->representation();
+    if ((checked_type.IsFloat32x4Type() && (rep == kUnboxedFloat32x4)) ||
+        (checked_type.IsUint32x4Type() && (rep == kUnboxedUint32x4))   ||
+        (checked_type.IsDoubleType() && (rep == kUnboxedDouble))       ||
+        (checked_type.IsIntType() && (rep == kUnboxedMint))) {
+      // The representation guarantees the type check to be true.

[Florian Schneider, 2013/10/03 09:06:55]

Maybe add an ASSERT that the compile-type of instr->value()->Type() matches with
the representation.

You could also use the type here - it should be slightly more general - i.e.
type checks on boxed values with a known type could be optimized as well: e.g.
smis

[Cutch, 2013/11/06 23:04:43]

Done.
I'll save that for a follow up CL.

+      SetValue(instr, instr->negate_result() ? Bool::False() : Bool::True());
+    } else {
+      SetValue(instr, non_constant_);
+    }
   } else if (IsConstant(value)) {
     // TODO(kmillikin): Handle instanceof on constants.
     SetValue(instr, non_constant_);
   }
 }
 
 
 void ConstantPropagator::VisitCreateArray(CreateArrayInstr* instr) {
   SetValue(instr, non_constant_);
 }
@@ skipping 1415 matching lines @@
   }
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, alloc->cls(), *fields);
   }
 }
 
 
 }  // namespace dart