Fix DoHasInstanceType on ARM

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index d244dc7c31ed1b583148ad90b9805d4d826e4e98..e89413a305190b9e2ef6ee62e8bc97a6d82971d6 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -1955,8 +1955,11 @@ void LCodeGen::DoHasInstanceType(LHasInstanceType* instr) {
 
   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);