Infer range for BIT_XOR.

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/cpu.h"
 #include "vm/dart_entry.h"
@@ skipping 732 matching lines @@
         unboxed = kUnboxedInt32x4;
       }
       break;
     case kFloat64x2Cid:
       if (ShouldInlineSimd()) {
         unboxed = kUnboxedFloat64x2;
       }
       break;
   }
 
+  if ((unboxed == kTagged) &&
+      phi->Type()->IsInt() &&
+      RangeUtils::Fits(phi->range(), RangeBoundary::kRangeBoundaryInt32)) {
+    bool should_unbox = false;
+    for (intptr_t i = 0; i < phi->InputCount(); i++) {
+      Definition* input = phi->InputAt(i)->definition();
+      if (input->IsBox() &&
+          RangeUtils::Fits(input->range(),
+                           RangeBoundary::kRangeBoundaryInt32)) {
+        should_unbox = true;
+      } else if (!input->IsConstant()) {
+        should_unbox = false;
+        break;
+      }
+    }
+
+    if (should_unbox) {
+      unboxed = kUnboxedInt32;
+    }
+  }
+
   phi->set_representation(unboxed);
 }
 
 
 void FlowGraphOptimizer::SelectRepresentations() {
   // Conservatively unbox all phis that were proven to be of Double,
   // Float32x4, or Int32x4 type.
   for (intptr_t i = 0; i < block_order_.length(); ++i) {
     JoinEntryInstr* join_entry = block_order_[i]->AsJoinEntry();
     if (join_entry != NULL) {
@@ skipping 9165 matching lines @@
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits_collector_.exits().length(); i++) {
     CreateMaterializationAt(
         exits_collector_.exits()[i], alloc, alloc->cls(), *slots);
   }
 }
 
 
 }  // namespace dart