Very small optimization of ARM compare stub.

src/arm/fast-codegen-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 1574 matching lines @@
           cc = eq;
           __ pop(r0);
           __ pop(r1);
           break;
         case Token::LT:
           cc = lt;
           __ pop(r0);
           __ pop(r1);
           break;
         case Token::GT:
-          // Reverse left and right sizes to obtain ECMA-262 conversion order.
+          // Reverse left and right sides to obtain ECMA-262 conversion order.
           cc = lt;
           __ pop(r1);
           __ pop(r0);
          break;
         case Token::LTE:
-          // Reverse left and right sizes to obtain ECMA-262 conversion order.
+          // Reverse left and right sides to obtain ECMA-262 conversion order.
           cc = ge;
           __ pop(r1);
           __ pop(r0);
           break;
         case Token::GTE:
           cc = ge;
           __ pop(r0);
           __ pop(r1);
           break;
         case Token::IN:
         case Token::INSTANCEOF:
         default:
           UNREACHABLE();
       }
 
       // The comparison stub expects the smi vs. smi case to be handled
       // before it is called.
       Label slow_case;
       __ orr(r2, r0, Operand(r1));
       __ tst(r2, Operand(kSmiTagMask));
       __ b(ne, &slow_case);
       __ cmp(r1, r0);
       __ b(cc, if_true);
       __ jmp(if_false);
 
       __ bind(&slow_case);
       CompareStub stub(cc, strict);
       __ CallStub(&stub);
-      __ tst(r0, r0);
+      __ cmp(r0, Operand(0));
       __ b(cc, if_true);
       __ jmp(if_false);
     }
   }
 
   // Convert the result of the comparison into one expected for this
   // expression's context.
   switch (expr->context()) {
     case Expression::kUninitialized:
       UNREACHABLE();
@@ skipping 81 matching lines @@
   __ pop(result_register());
   ASSERT_EQ(1, kSmiTagSize + kSmiShiftSize);
   __ mov(r1, Operand(r1, ASR, 1));  // Un-smi-tag value.
   __ add(pc, r1, Operand(masm_->CodeObject()));
 }
 
 
 #undef __
 
 } }  // namespace v8::internal