LoadUint32() doesn't need a scratch register.

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #if V8_TARGET_ARCH_IA32
 
 #include "ia32/lithium-codegen-ia32.h"
 #include "ic.h"
@@ skipping 4429 matching lines @@
   LOperand* output = instr->result();
   ASSERT(input->IsRegister() || input->IsStackSlot());
   ASSERT(output->IsDoubleRegister());
   __ Cvtsi2sd(ToDoubleRegister(output), ToOperand(input));
 }
 
 
 void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
   LOperand* input = instr->value();
   LOperand* output = instr->result();
-  LOperand* temp = instr->temp();
-  __ LoadUint32(ToDoubleRegister(output),
-                ToRegister(input),
-                ToDoubleRegister(temp));
+  __ LoadUint32(ToDoubleRegister(output), ToRegister(input));
 }
 
 
 void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
   class DeferredNumberTagI V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagI(LCodeGen* codegen,
                        LNumberTagI* instr)
         : LDeferredCode(codegen), instr_(instr) { }
     virtual void Generate() V8_OVERRIDE {
-      codegen()->DoDeferredNumberTagIU(instr_, instr_->value(), instr_->temp(),
-                                       NULL, SIGNED_INT32);
+      codegen()->DoDeferredNumberTagIU(
+          instr_, instr_->value(), instr_->temp(), SIGNED_INT32);
     }
     virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagI* instr_;
   };
 
   LOperand* input = instr->value();
   ASSERT(input->IsRegister() && input->Equals(instr->result()));
   Register reg = ToRegister(input);
 
   DeferredNumberTagI* deferred =
       new(zone()) DeferredNumberTagI(this, instr);
   __ SmiTag(reg);
   __ j(overflow, deferred->entry());
   __ bind(deferred->exit());
 }
 
 
 void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
   class DeferredNumberTagU V8_FINAL : public LDeferredCode {
    public:
     DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
         : LDeferredCode(codegen), instr_(instr) { }
     virtual void Generate() V8_OVERRIDE {
-      codegen()->DoDeferredNumberTagIU(instr_, instr_->value(), instr_->temp1(),
-                                       instr_->temp2(), UNSIGNED_INT32);
+      codegen()->DoDeferredNumberTagIU(
+          instr_, instr_->value(), instr_->temp(), UNSIGNED_INT32);
     }
     virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LNumberTagU* instr_;
   };
 
   LOperand* input = instr->value();
   ASSERT(input->IsRegister() && input->Equals(instr->result()));
   Register reg = ToRegister(input);
 
   DeferredNumberTagU* deferred =
       new(zone()) DeferredNumberTagU(this, instr);
   __ cmp(reg, Immediate(Smi::kMaxValue));
   __ j(above, deferred->entry());
   __ SmiTag(reg);
   __ bind(deferred->exit());
 }
 
 
 void LCodeGen::DoDeferredNumberTagIU(LInstruction* instr,
                                      LOperand* value,
-                                     LOperand* temp1,
-                                     LOperand* temp2,
+                                     LOperand* temp,
                                      IntegerSignedness signedness) {
   Label done, slow;
   Register reg = ToRegister(value);
-  Register tmp = ToRegister(temp1);
+  Register tmp = ToRegister(temp);
   XMMRegister xmm_scratch = double_scratch0();
 
   if (signedness == SIGNED_INT32) {
     // There was overflow, so bits 30 and 31 of the original integer
     // disagree. Try to allocate a heap number in new space and store
     // the value in there. If that fails, call the runtime system.
     __ SmiUntag(reg);
     __ xor_(reg, 0x80000000);
     __ Cvtsi2sd(xmm_scratch, Operand(reg));
   } else {
-    __ LoadUint32(xmm_scratch, reg, ToDoubleRegister(temp2));
+    __ LoadUint32(xmm_scratch, reg);
   }
 
   if (FLAG_inline_new) {
     __ AllocateHeapNumber(reg, tmp, no_reg, &slow);
     __ jmp(&done, Label::kNear);
   }
 
   // Slow case: Call the runtime system to do the number allocation.
   __ bind(&slow);
   {
@@ skipping 1130 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32