Slightly improved register assignment for %_IsObject on IA32 and 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 1778 matching lines @@
     __ ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset));
     __ ldrb(scratch, FieldMemOperand(scratch, Map::kBitFieldOffset));
     __ tst(scratch, Operand(1 << Map::kIsUndetectable));
     EmitBranch(true_block, false_block, ne);
   }
 }
 
 
 Condition LCodeGen::EmitIsObject(Register input,
                                  Register temp1,
-                                 Register temp2,
                                  Label* is_not_object,
                                  Label* is_object) {
+  Register temp2 = scratch0();
   __ JumpIfSmi(input, is_not_object);
 
-  __ LoadRoot(temp1, Heap::kNullValueRootIndex);
-  __ cmp(input, temp1);
+  __ LoadRoot(temp2, Heap::kNullValueRootIndex);
+  __ cmp(input, temp2);
   __ b(eq, is_object);
 
   // Load map.
   __ ldr(temp1, FieldMemOperand(input, HeapObject::kMapOffset));
   // Undetectable objects behave like undefined.
   __ ldrb(temp2, FieldMemOperand(temp1, Map::kBitFieldOffset));
   __ tst(temp2, Operand(1 << Map::kIsUndetectable));
   __ b(ne, is_not_object);
 
   // Load instance type and check that it is in object type range.
   __ ldrb(temp2, FieldMemOperand(temp1, Map::kInstanceTypeOffset));
   __ cmp(temp2, Operand(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
   __ b(lt, is_not_object);
   __ cmp(temp2, Operand(LAST_NONCALLABLE_SPEC_OBJECT_TYPE));
   return le;
 }
 
 
 void LCodeGen::DoIsObject(LIsObject* instr) {
   Register reg = ToRegister(instr->InputAt(0));
   Register result = ToRegister(instr->result());
-  Register temp = scratch0();
   Label is_false, is_true, done;
 
-  Condition true_cond = EmitIsObject(reg, result, temp, &is_false, &is_true);
+  Condition true_cond = EmitIsObject(reg, result, &is_false, &is_true);
   __ b(true_cond, &is_true);
 
   __ bind(&is_false);
   __ LoadRoot(result, Heap::kFalseValueRootIndex);
   __ b(&done);
 
   __ bind(&is_true);
   __ LoadRoot(result, Heap::kTrueValueRootIndex);
 
   __ bind(&done);
 }
 
 
 void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
   Register reg = ToRegister(instr->InputAt(0));
   Register temp1 = ToRegister(instr->TempAt(0));
   Register temp2 = scratch0();
 
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
   Label* true_label = chunk_->GetAssemblyLabel(true_block);
   Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
   Condition true_cond =
-      EmitIsObject(reg, temp1, temp2, false_label, true_label);
+      EmitIsObject(reg, temp1, false_label, true_label);
 
   EmitBranch(true_block, false_block, true_cond);
 }
 
 
 void LCodeGen::DoIsSmi(LIsSmi* instr) {
   ASSERT(instr->hydrogen()->value()->representation().IsTagged());
   Register result = ToRegister(instr->result());
   Register input_reg = EmitLoadRegister(instr->InputAt(0), ip);
   Label done;
@@ skipping 2735 matching lines @@
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 
 
 
 #undef __
 
 } }  // namespace v8::internal