[interpreter] Teach register optimizer about SuspendGenerator.

src/interpreter/bytecode-register-optimizer.cc

 // Copyright 2016 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.
 
 #include "src/interpreter/bytecode-register-optimizer.h"
 
 namespace v8 {
 namespace internal {
 namespace interpreter {
 
@@ skipping 228 matching lines @@
     }
     case Bytecode::kMov: {
       DoMov(node);
       return;
     }
     default:
       break;
   }
 
   if (Bytecodes::IsJump(node->bytecode()) ||
-      node->bytecode() == Bytecode::kDebugger) {
-    // The debugger can manipulate locals and parameters, flush
-    // everything before handing over to it. Similarly, all state must
-    // be flushed before emitting a jump due to how bytecode offsets
-    // for jumps are evaluated.
+      node->bytecode() == Bytecode::kDebugger ||
+      node->bytecode() == Bytecode::kSuspendGenerator) {
+    // All state must be flushed before emitting
+    // - a jump (due to how bytecode offsets for jumps are evaluated),
+    // - a call to the debugger (as it can manipulate locals and parameters),
+    // - a generator suspend (as this involves saving all registers).
     FlushState();
   }
 
   PrepareOperands(node);
   WriteToNextStage(node);
 }
 
 // override
 void BytecodeRegisterOptimizer::WriteJump(BytecodeNode* node,
                                           BytecodeLabel* label) {
@@ skipping 353 matching lines @@
     if (info->materialized()) {
       CreateMaterializedEquivalent(info);
     }
     info->MoveToNewEquivalenceSet(kInvalidEquivalenceId, false);
   }
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8