Simplify some code related to x64 calling convention.

src/x64/lithium-x64.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 1538 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoPower(HPower* instr) {
   ASSERT(instr->representation().IsDouble());
   // We call a C function for double power. It can't trigger a GC.
   // We need to use fixed result register for the call.
   Representation exponent_type = instr->right()->representation();
   ASSERT(instr->left()->representation().IsDouble());
   LOperand* left = UseFixedDouble(instr->left(), xmm2);
   LOperand* right = exponent_type.IsDouble() ?
-      UseFixedDouble(instr->right(), xmm1) :
-#ifdef _WIN64
-      UseFixed(instr->right(), rdx);
-#else
-      UseFixed(instr->right(), rdi);
-#endif
+      UseFixedDouble(instr->right(), xmm1) : UseFixed(instr->right(), rdx);
   LPower* result = new(zone()) LPower(left, right);
   return MarkAsCall(DefineFixedDouble(result, xmm3), instr,
                     CAN_DEOPTIMIZE_EAGERLY);
 }
 
 
 LInstruction* LChunkBuilder::DoRandom(HRandom* instr) {
   ASSERT(instr->representation().IsDouble());
   ASSERT(instr->global_object()->representation().IsTagged());
-#ifdef _WIN64
-  LOperand* global_object = UseFixed(instr->global_object(), rcx);
-#else
-  LOperand* global_object = UseFixed(instr->global_object(), rdi);
-#endif
+  LOperand* global_object = UseFixed(instr->global_object(), arg_reg_1);
   LRandom* result = new(zone()) LRandom(global_object);
   return MarkAsCall(DefineFixedDouble(result, xmm1), instr);
 }
 
 
 LInstruction* LChunkBuilder::DoCompareGeneric(HCompareGeneric* instr) {
   ASSERT(instr->left()->representation().IsTagged());
   ASSERT(instr->right()->representation().IsTagged());
   LOperand* left = UseFixed(instr->left(), rdx);
   LOperand* right = UseFixed(instr->right(), rax);
@@ skipping 981 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   return DefineSameAsFirst(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64