Fix DoHasInstanceType on ARM

src/arm/lithium-codegen-arm.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 1937 matching lines @@
   return eq;
 }
 
 
 void LCodeGen::DoHasInstanceType(LHasInstanceType* instr) {
   Register input = ToRegister(instr->InputAt(0));
   Register result = ToRegister(instr->result());
 
   ASSERT(instr->hydrogen()->value()->representation().IsTagged());
   Label done;
+  // TODO(jkummerow): Would like to replace this by JumpIfSmi(), but it's
+  // non-trivial.
+  __ tst(input, Operand(kSmiTagMask));

[Do not use this email for V8, 2011/06/20 12:41:46]

The comment isn't necessary, or it could just say "We can't use JumpIfSmi() here
because of the dependent load."

[Søren Thygesen Gjesse, 2011/06/21 10:03:02]

Can't we just have a macro assembler instruction TestIfSmi for use in places
where the  condition code is used several times?

   __ LoadRoot(result, Heap::kFalseValueRootIndex, eq);
-  __ JumpIfSmi(input, &done);
+  __ b(eq, &done);
   __ CompareObjectType(input, result, result, TestType(instr->hydrogen()));
   Condition cond = BranchCondition(instr->hydrogen());
   __ LoadRoot(result, Heap::kTrueValueRootIndex, cond);
   __ LoadRoot(result, Heap::kFalseValueRootIndex, NegateCondition(cond));
   __ bind(&done);
 }
 
 
 void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
   Register scratch = scratch0();
@@ skipping 2611 matching lines @@
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 
 
 
 #undef __
 
 } }  // namespace v8::internal