Remove 'unanimous use observations' rule from Phi representation inference

src/hydrogen-instructions.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3489 matching lines @@
     if (use->IsBinaryOperation()) {
       HBinaryOperation::cast(use)->set_observed_input_representation(
           it.index(), Representation::Integer32());
     }
   }
 }
 
 
 void HPhi::InferRepresentation(HInferRepresentation* h_infer) {
   ASSERT(CheckFlag(kFlexibleRepresentation));
-  // If there are non-Phi uses, and all of them have observed the same
-  // representation, than that's what this Phi is going to use.
-  Representation new_rep = RepresentationObservedByAllNonPhiUses();
-  if (!new_rep.IsNone()) {
-    UpdateRepresentation(new_rep, h_infer, "unanimous use observations");
-    return;
-  }
-  new_rep = RepresentationFromInputs();
+  Representation new_rep = RepresentationFromInputs();
   UpdateRepresentation(new_rep, h_infer, "inputs");
   new_rep = RepresentationFromUses();
   UpdateRepresentation(new_rep, h_infer, "uses");
   new_rep = RepresentationFromUseRequirements();
   UpdateRepresentation(new_rep, h_infer, "use requirements");
 }
 
 
-Representation HPhi::RepresentationObservedByAllNonPhiUses() {
-  int non_phi_use_count = 0;
-  for (int i = Representation::kInteger32;
-       i < Representation::kNumRepresentations; ++i) {
-    non_phi_use_count += non_phi_uses_[i];
-  }
-  if (non_phi_use_count <= 1) return Representation::None();
-  for (int i = 0; i < Representation::kNumRepresentations; ++i) {
-    if (non_phi_uses_[i] == non_phi_use_count) {
-      return Representation::FromKind(static_cast<Representation::Kind>(i));
-    }
-  }
-  return Representation::None();
-}
-
-
 Representation HPhi::RepresentationFromInputs() {
   bool double_occurred = false;
   bool int32_occurred = false;
   for (int i = 0; i < OperandCount(); ++i) {
     HValue* value = OperandAt(i);
     if (value->IsUnknownOSRValue()) {
       HPhi* hint_value = HUnknownOSRValue::cast(value)->incoming_value();
       if (hint_value != NULL) {
         Representation hint = hint_value->representation();
         if (hint.IsTagged()) return hint;
@@ skipping 95 matching lines @@
 
 
 void HCheckFunction::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal