Make TestJSArrayForAllocationMemento less awkward.

src/x64/macro-assembler-x64.h

 // 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 1394 matching lines @@
   // Expects object in rax and returns map with validated enum cache
   // in rax.  Assumes that any other register can be used as a scratch.
   void CheckEnumCache(Register null_value,
                       Label* call_runtime);
 
   // AllocationMemento support. Arrays may have an associated
   // AllocationMemento object that can be checked for in order to pretransition
   // to another type.
   // On entry, receiver_reg should point to the array object.
   // scratch_reg gets clobbered.
-  // If allocation info is present, condition flags are set to equal
+  // If allocation info is present, condition flags are set to equal.
   void TestJSArrayForAllocationMemento(Register receiver_reg,
-                                       Register scratch_reg);
+                                       Register scratch_reg,
+                                       Label* no_memento_found);
+
+  void JumpIfJSArrayHasAllocationMemento(Register receiver_reg,
+                                         Register scratch_reg,
+                                         Label* memento_found) {
+    Label no_memento_found;
+    TestJSArrayForAllocationMemento(receiver_reg, scratch_reg,
+                                    &no_memento_found);
+    j(equal, memento_found);
+    bind(&no_memento_found);
+  }
 
  private:
   // Order general registers are pushed by Pushad.
   // rax, rcx, rdx, rbx, rsi, rdi, r8, r9, r11, r14, r15.
   static const int kSafepointPushRegisterIndices[Register::kNumRegisters];
   static const int kNumSafepointSavedRegisters = 11;
   static const int kSmiShift = kSmiTagSize + kSmiShiftSize;
 
   bool generating_stub_;
   bool allow_stub_calls_;
@@ skipping 164 matching lines @@
     masm->popfq();                                                           \
   }                                                                          \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_