Config double register number as 1 for X87 Turbofan.

src/x87/assembler-x87.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 133 matching lines @@
 }
 
 
 struct X87Register {
   static const int kMaxNumAllocatableRegisters = 6;
   static const int kMaxNumRegisters = 8;
   static int NumAllocatableRegisters() {
     return kMaxNumAllocatableRegisters;
   }
 
-
   // TODO(turbofan): Proper support for float32.
   static int NumAllocatableAliasedRegisters() {
     return NumAllocatableRegisters();
   }
 
+  static int NumAllocatableRegistersForTurbo() {
+    return 1;
+  }
+
+  static int NumAllocatableAliasedRegistersForTurbo() {
+    return NumAllocatableRegistersForTurbo();
+  }
 
   static int ToAllocationIndex(X87Register reg) {
     return reg.code_;
   }
 
   static const char* AllocationIndexToString(int index) {
     DCHECK(index >= 0 && index < kMaxNumAllocatableRegisters);
     const char* const names[] = {
       "stX_0", "stX_1", "stX_2", "stX_3", "stX_4",
       "stX_5", "stX_6", "stX_7"
@@ skipping 913 matching lines @@
  private:
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X87_ASSEMBLER_X87_H_