Use xorps to break the cvtsi2sd unnecessary dependence due to its partially written

src/ia32/macro-assembler-ia32.cc

 // Copyright 2012 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 265 matching lines @@
 
 
 void MacroAssembler::DoubleToI(Register result_reg,
                                XMMRegister input_reg,
                                XMMRegister scratch,
                                MinusZeroMode minus_zero_mode,
                                Label* conversion_failed,
                                Label::Distance dst) {
   ASSERT(!input_reg.is(scratch));
   cvttsd2si(result_reg, Operand(input_reg));
-  cvtsi2sd(scratch, Operand(result_reg));
+  Cvtsi2sd(scratch, Operand(result_reg));
   ucomisd(scratch, input_reg);
   j(not_equal, conversion_failed, dst);
   j(parity_even, conversion_failed, dst);  // NaN.
   if (minus_zero_mode == FAIL_ON_MINUS_ZERO) {
     Label done;
     // The integer converted back is equal to the original. We
     // only have to test if we got -0 as an input.
     test(result_reg, Operand(result_reg));
     j(not_zero, &done, Label::kNear);
     movmskpd(result_reg, input_reg);
@@ skipping 88 matching lines @@
   cmp(FieldOperand(input_reg, HeapObject::kMapOffset),
       isolate()->factory()->heap_number_map());
   j(not_equal, lost_precision, Label::kNear);
 
   if (CpuFeatures::IsSafeForSnapshot(SSE2)) {
     ASSERT(!temp.is(no_xmm_reg));
     CpuFeatureScope scope(this, SSE2);
 
     movdbl(xmm0, FieldOperand(input_reg, HeapNumber::kValueOffset));
     cvttsd2si(result_reg, Operand(xmm0));
-    cvtsi2sd(temp, Operand(result_reg));
+    Cvtsi2sd(temp, Operand(result_reg));
     ucomisd(xmm0, temp);
     RecordComment("Deferred TaggedToI: lost precision");
     j(not_equal, lost_precision, Label::kNear);
     RecordComment("Deferred TaggedToI: NaN");
     j(parity_even, lost_precision, Label::kNear);
     if (minus_zero_mode == FAIL_ON_MINUS_ZERO) {
       test(result_reg, Operand(result_reg));
       j(not_zero, &done, Label::kNear);
       movmskpd(result_reg, xmm0);
       and_(result_reg, 1);
@@ skipping 44 matching lines @@
     static_cast<double>(static_cast<uint32_t>(0xFFFFFFFF)) + 1;
 
 
 void MacroAssembler::LoadUint32(XMMRegister dst,
                                 Register src,
                                 XMMRegister scratch) {
   Label done;
   cmp(src, Immediate(0));
   movdbl(scratch,
          Operand(reinterpret_cast<int32_t>(&kUint32Bias), RelocInfo::NONE32));
-  cvtsi2sd(dst, src);
+  Cvtsi2sd(dst, src);
   j(not_sign, &done, Label::kNear);
   addsd(dst, scratch);
   bind(&done);
 }
 
 
 void MacroAssembler::RecordWriteArray(Register object,
                                       Register value,
                                       Register index,
                                       SaveFPRegsMode save_fp,
@@ skipping 198 matching lines @@
 #ifdef ENABLE_DEBUGGER_SUPPORT
 void MacroAssembler::DebugBreak() {
   Set(eax, Immediate(0));
   mov(ebx, Immediate(ExternalReference(Runtime::kDebugBreak, isolate())));
   CEntryStub ces(1);
   call(ces.GetCode(isolate()), RelocInfo::DEBUG_BREAK);
 }
 #endif
 
 
+void MacroAssembler::Cvtsi2sd(XMMRegister dst, const Operand& src) {
+  xorps(dst, dst);
+  cvtsi2sd(dst, src);
+}
+
+
 void MacroAssembler::Set(Register dst, const Immediate& x) {
   if (x.is_zero()) {
     xor_(dst, dst);  // Shorter than mov.
   } else {
     mov(dst, x);
   }
 }
 
 
 void MacroAssembler::Set(const Operand& dst, const Immediate& x) {
@@ skipping 138 matching lines @@
   }
   jmp(&have_double_value, Label::kNear);
 
   bind(&smi_value);
   // Value is a smi. Convert to a double and store.
   // Preserve original value.
   mov(scratch1, maybe_number);
   SmiUntag(scratch1);
   if (CpuFeatures::IsSupported(SSE2) && specialize_for_processor) {
     CpuFeatureScope fscope(this, SSE2);
-    cvtsi2sd(scratch2, scratch1);
+    Cvtsi2sd(scratch2, scratch1);
     movdbl(FieldOperand(elements, key, times_4,
                         FixedDoubleArray::kHeaderSize - elements_offset),
            scratch2);
   } else {
     push(scratch1);
     fild_s(Operand(esp, 0));
     pop(scratch1);
     fstp_d(FieldOperand(elements, key, times_4,
                         FixedDoubleArray::kHeaderSize - elements_offset));
   }
@@ skipping 2576 matching lines @@
   j(greater, &no_memento_available);
   cmp(MemOperand(scratch_reg, -AllocationMemento::kSize),
       Immediate(Handle<Map>(isolate()->heap()->allocation_memento_map())));
   bind(&no_memento_available);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32