Slightly improved register assignment for %_IsObject on IA32 and ARM.

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
===================================================================
--- src/ia32/lithium-ia32.cc	(revision 8444)
+++ src/ia32/lithium-ia32.cc	(working copy)
@@ -1096,11 +1096,8 @@
   } else if (v->IsIsObject()) {
     HIsObject* compare = HIsObject::cast(v);
     ASSERT(compare->value()->representation().IsTagged());
-    LOperand* temp1 = TempRegister();
-    LOperand* temp2 = TempRegister();
-    return new LIsObjectAndBranch(UseRegister(compare->value()),
-                                  temp1,
-                                  temp2);
+    LOperand* temp = TempRegister();
+    return new LIsObjectAndBranch(UseRegister(compare->value()), temp);
   } else if (v->IsCompareObjectEq()) {
     HCompareObjectEq* compare = HCompareObjectEq::cast(v);
     return new LCmpObjectEqAndBranch(UseRegisterAtStart(compare->left()),
@@ -1546,7 +1543,7 @@
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* value = UseRegister(instr->value());
 
-  return DefineAsRegister(new LIsObject(value, TempRegister()));
+  return DefineAsRegister(new LIsObject(value));
 }