[interpreter] Make sure allocated registers are always materialized in the register optimizer.

BUG=chromium:729369

Review-Url: https://codereview.chromium.org/2926063002
Cr-Commit-Position: refs/heads/master@{#45770}

src/interpreter/bytecode-register-optimizer.cc

@@ -416,8 +416,15 @@ void BytecodeRegisterOptimizer::GrowRegisterMap(Register reg) {
   }
 }
 
+void BytecodeRegisterOptimizer::AllocateRegister(RegisterInfo* info) {
+  info->set_allocated(true);
+  if (!info->materialized()) {
+    info->MoveToNewEquivalenceSet(NextEquivalenceId(), true);
+  }
+}
+
 void BytecodeRegisterOptimizer::RegisterAllocateEvent(Register reg) {
-  GetOrCreateRegisterInfo(reg)->set_allocated(true);
+  AllocateRegister(GetOrCreateRegisterInfo(reg));
 }
 
 void BytecodeRegisterOptimizer::RegisterListAllocateEvent(
@@ -426,7 +433,7 @@ void BytecodeRegisterOptimizer::RegisterListAllocateEvent(
     int first_index = reg_list.first_register().index();
     GrowRegisterMap(Register(first_index + reg_list.register_count() - 1));
     for (int i = 0; i < reg_list.register_count(); i++) {
-      GetRegisterInfo(Register(first_index + i))->set_allocated(true);
+      AllocateRegister(GetRegisterInfo(Register(first_index + i)));
     }
   }
 }

src/interpreter/bytecode-register-optimizer.h

@@ -178,6 +178,8 @@ class V8_EXPORT_PRIVATE BytecodeRegisterOptimizer final
     return equivalence_id_;
   }
 
+  void AllocateRegister(RegisterInfo* info);
+
   Zone* zone() { return zone_; }
 
   const Register accumulator_;

test/cctest/interpreter/bytecode_expectations/ObjectLiterals.golden

@@ -335,7 +335,7 @@ snippet: "
 "
 frame size: 5
 parameter count: 1
-bytecode array length: 40
+bytecode array length: 38
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaConstant), U8(0),
@@ -345,7 +345,6 @@ bytecodes: [
                 B(LdaSmi), I8(1),
                 B(StaDataPropertyInLiteral), R(1), R(2), U8(0), U8(5),
                 B(CreateObjectLiteral), U8(1), U8(3), U8(19), R(4),
-                B(Star), R(3),
                 B(Mov), R(1), R(2),
                 B(Mov), R(4), R(3),
                 B(CallRuntime), U16(Runtime::kInternalSetPrototype), R(2), U8(2),
@@ -365,7 +364,7 @@ snippet: "
 "
 frame size: 6
 parameter count: 1
-bytecode array length: 63
+bytecode array length: 61
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaConstant), U8(0),
@@ -374,7 +373,6 @@ bytecodes: [
   /*   60 E> */ B(ToName), R(2),
                 B(LdaConstant), U8(2),
                 B(StaDataPropertyInLiteral), R(1), R(2), U8(0), U8(6),
-                B(Star), R(3),
                 B(LdaConstant), U8(3),
                 B(Star), R(3),
                 B(CreateClosure), U8(4), U8(3), U8(2),

test/mjsunit/compiler/regress-729369.js

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax
+
+function* f() {
+  x.__defineGetter__();
+  var x = 0;
+  for (let y of iterable) {
+    yield y;
+  }
+}
+
+f();