Backport r6579 (code generation bug on ARM).

src/arm/virtual-frame-arm.cc

 // Copyright 2009 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 50 matching lines @@
   // Shuffle things around so the top of stack only in r0.
   MergeTOSTo(R0_TOS);
   // Pop the register off the stack so it is detached from the frame.
   LowerHeight(1);
   top_of_stack_state_ = NO_TOS_REGISTERS;
 }
 
 
 void VirtualFrame::MergeTo(const VirtualFrame* expected, Condition cond) {
   if (Equals(expected)) return;
+  ASSERT((expected->tos_known_smi_map_ & tos_known_smi_map_) ==
+         expected->tos_known_smi_map_);
   ASSERT(expected->IsCompatibleWith(this));
   MergeTOSTo(expected->top_of_stack_state_, cond);
   ASSERT(register_allocation_map_ == expected->register_allocation_map_);
 }
 
 
 void VirtualFrame::MergeTo(VirtualFrame* expected, Condition cond) {
   if (Equals(expected)) return;
-  expected->tos_known_smi_map_ &= tos_known_smi_map_;
+  tos_known_smi_map_ &= expected->tos_known_smi_map_;
   MergeTOSTo(expected->top_of_stack_state_, cond);
   ASSERT(register_allocation_map_ == expected->register_allocation_map_);
 }
 
 
 void VirtualFrame::MergeTOSTo(
     VirtualFrame::TopOfStack expected_top_of_stack_state, Condition cond) {
 #define CASE_NUMBER(a, b) ((a) * TOS_STATES + (b))
   switch (CASE_NUMBER(top_of_stack_state_, expected_top_of_stack_state)) {
     case CASE_NUMBER(NO_TOS_REGISTERS, NO_TOS_REGISTERS):
@@ skipping 733 matching lines @@
       break;
   }
   ASSERT(register_allocation_map_ == 0);  // Not yet implemented.
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM