Add dynamic stack frame alignment to optimized functions with untagged doubles on the stack.

src/ia32/lithium-ia32.cc

 // Copyright 2011 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 334 matching lines @@
   stream->Add(" length ");
   length()->PrintTo(stream);
 
   stream->Add(" index ");
   index()->PrintTo(stream);
 }
 
 
 int LChunk::GetNextSpillIndex(bool is_double) {
   // Skip a slot if for a double-width slot.
-  if (is_double) spill_slot_count_++;
+  if (is_double) {
+    spill_slot_count_ |= 1;  // Make it odd, so incrementing makes it even.
+    spill_slot_count_++;
+    num_double_slots_++;
+  }
   return spill_slot_count_++;
 }
 
 
 LOperand* LChunk::GetNextSpillSlot(bool is_double) {
   int index = GetNextSpillIndex(is_double);
   if (is_double) {
     return LDoubleStackSlot::Create(index);
   } else {
     return LStackSlot::Create(index);
@@ skipping 1902 matching lines @@
   LOperand* key = UseOrConstantAtStart(instr->key());
   LOperand* object = UseOrConstantAtStart(instr->object());
   LIn* result = new LIn(context, key, object);
   return MarkAsCall(DefineFixed(result, eax), instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32