S390: Use TM instead of TMLL in case of memory operand.

src/s390/macro-assembler-s390.h

 // Copyright 2014 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.
 
 #ifndef V8_S390_MACRO_ASSEMBLER_S390_H_
 #define V8_S390_MACRO_ASSEMBLER_S390_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/frames.h"
@@ skipping 1534 matching lines @@
             true);
     }
   }
 
   // Untag the source value into destination and jump if source is a smi.
   // Souce and destination can be the same register.
   void UntagAndJumpIfSmi(Register dst, Register src, Label* smi_case);
 
   inline void TestIfSmi(Register value) { tmll(value, Operand(1)); }
 
+  inline void TestIfSmi(MemOperand value) {
+    if (is_uint12(value.offset())) {
+      tm(value, Operand(1));
+    } else if (is_int20(value.offset())) {
+      tmy(value, Operand(1));
+    } else {
+      UNIMPLEMENTED();

[JoranSiu, 2016/12/19 16:25:33]

A bit concerned about this unimplemented path... as it'll likely be a matter of
time before we hit this. :|  

+    }
+  }
+
   inline void TestIfPositiveSmi(Register value, Register scratch) {
     STATIC_ASSERT((kSmiTagMask | kSmiSignMask) ==
                   (intptr_t)(1UL << (kBitsPerPointer - 1) | 1));
     mov(scratch, Operand(kIntptrSignBit | kSmiTagMask));
     AndP(scratch, value);
   }
 
   // Jump the register contains a smi.
   inline void JumpIfSmi(Register value, Label* smi_label) {
     TestIfSmi(value);
@@ skipping 258 matching lines @@
 inline MemOperand NativeContextMemOperand() {
   return ContextMemOperand(cp, Context::NATIVE_CONTEXT_INDEX);
 }
 
 #define ACCESS_MASM(masm) masm->
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_S390_MACRO_ASSEMBLER_S390_H_