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

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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 3502 matching lines @@
     __ cvttsd2si(output_reg, input_reg);
     // Overflow is signalled with minint.
     __ cmpl(output_reg, Immediate(0x80000000));
     DeoptimizeIf(equal, instr->environment());
     __ jmp(&done, Label::kNear);
 
     // Non-zero negative reaches here.
     __ bind(&negative_sign);
     // Truncate, then compare and compensate.
     __ cvttsd2si(output_reg, input_reg);
-    __ cvtlsi2sd(xmm_scratch, output_reg);
+    __ Cvtlsi2sd(xmm_scratch, output_reg);
     __ ucomisd(input_reg, xmm_scratch);
     __ j(equal, &done, Label::kNear);
     __ subl(output_reg, Immediate(1));
     DeoptimizeIf(overflow, instr->environment());
 
     __ bind(&done);
   }
 }
 
 
@@ skipping 28 matching lines @@
   // CVTTSD2SI rounds towards zero, we use ceil(x - (-0.5)) and then
   // compare and compensate.
   __ movq(kScratchRegister, input_reg);  // Back up input_reg.
   __ subsd(input_reg, xmm_scratch);
   __ cvttsd2si(output_reg, input_reg);
   // Catch minint due to overflow, and to prevent overflow when compensating.
   __ cmpl(output_reg, Immediate(0x80000000));
   __ RecordComment("D2I conversion overflow");
   DeoptimizeIf(equal, instr->environment());
 
-  __ cvtlsi2sd(xmm_scratch, output_reg);
+  __ Cvtlsi2sd(xmm_scratch, output_reg);
   __ ucomisd(input_reg, xmm_scratch);
   __ j(equal, &restore, Label::kNear);
   __ subl(output_reg, Immediate(1));
   // No overflow because we already ruled out minint.
   __ bind(&restore);
   __ movq(input_reg, kScratchRegister);  // Restore input_reg.
   __ jmp(&done);
 
   __ bind(&round_to_zero);
   // We return 0 for the input range [+0, 0.5[, or [-0.5, 0.5[ if
@@ skipping 859 matching lines @@
   __ StoreToSafepointRegisterSlot(result, rax);
 }
 
 
 void LCodeGen::DoInteger32ToDouble(LInteger32ToDouble* instr) {
   LOperand* input = instr->value();
   ASSERT(input->IsRegister() || input->IsStackSlot());
   LOperand* output = instr->result();
   ASSERT(output->IsDoubleRegister());
   if (input->IsRegister()) {
-    __ cvtlsi2sd(ToDoubleRegister(output), ToRegister(input));
+    __ Cvtlsi2sd(ToDoubleRegister(output), ToRegister(input));
   } else {
-    __ cvtlsi2sd(ToDoubleRegister(output), ToOperand(input));
+    __ Cvtlsi2sd(ToDoubleRegister(output), ToOperand(input));
   }
 }
 
 
 void LCodeGen::DoInteger32ToSmi(LInteger32ToSmi* instr) {
   LOperand* input = instr->value();
   ASSERT(input->IsRegister());
   LOperand* output = instr->result();
   __ Integer32ToSmi(ToRegister(output), ToRegister(input));
   if (!instr->hydrogen()->value()->HasRange() ||
@@ skipping 196 matching lines @@
       DeoptimizeIf(not_zero, env);
     }
     __ jmp(&done, Label::kNear);
   } else {
     ASSERT(mode == NUMBER_CANDIDATE_IS_SMI);
   }
 
   // Smi to XMM conversion
   __ bind(&load_smi);
   __ SmiToInteger32(kScratchRegister, input_reg);
-  __ cvtlsi2sd(result_reg, kScratchRegister);
+  __ Cvtlsi2sd(result_reg, kScratchRegister);
   __ bind(&done);
 }
 
 
 void LCodeGen::DoDeferredTaggedToI(LTaggedToI* instr, Label* done) {
   Label heap_number;
   Register input_reg = ToRegister(instr->value());
 
 
   if (instr->truncating()) {
@@ skipping 811 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64