[x64] Make xmm0 allocatable and use xmm15 as scratch register instead.

src/x64/codegen-x64.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 "src/x64/codegen-x64.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/codegen.h"
 #include "src/macro-assembler.h"
@@ skipping 225 matching lines @@
   __ jmp(&done);
 
   // Conversion loop.
   __ bind(&loop);
   __ movp(rbx,
           FieldOperand(r8, r9, times_pointer_size, FixedArray::kHeaderSize));
   // r9 : current element's index
   // rbx: current element (smi-tagged)
   __ JumpIfNotSmi(rbx, &convert_hole);
   __ SmiToInteger32(rbx, rbx);
-  __ Cvtlsi2sd(xmm0, rbx);
-  __ Movsd(FieldOperand(r14, r9, times_8, FixedDoubleArray::kHeaderSize), xmm0);
+  __ Cvtlsi2sd(kScratchDoubleReg, rbx);
+  __ Movsd(FieldOperand(r14, r9, times_8, FixedDoubleArray::kHeaderSize),
+           kScratchDoubleReg);
   __ jmp(&entry);
   __ bind(&convert_hole);
 
   if (FLAG_debug_code) {
     __ CompareRoot(rbx, Heap::kTheHoleValueRootIndex);
     __ Assert(equal, kObjectFoundInSmiOnlyArray);
   }
 
   __ movq(FieldOperand(r14, r9, times_8, FixedDoubleArray::kHeaderSize), r15);
   __ bind(&entry);
@@ skipping 376 matching lines @@
     return Operand(base_reg_, argument_count_reg_, times_pointer_size,
         displacement_to_last_argument + (receiver - 1 - index) * kPointerSize);
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64