Merge pull request #2928 from Sonicadvance1/remove_x18_saving

Arm64Emitter: Stop saving and restoring platform register

FEXCore/Source/Interface/Core/ArchHelpers/Arm64Emitter.cpp

@@ -22,7 +22,7 @@
 namespace FEXCore::CPU {
 // Register x18 is unused in the current configuration.
 // This is due to it being a platform register on wine platforms.
-// TODO: Allow x18 register allocation in the future to gain one more register.
+// TODO: Allow x18 register allocation on Linux in the future to gain one more register.
 
 namespace x64 {
   // All but x19 and x29 are caller saved
@@ -310,10 +310,6 @@ void Arm64Emitter::PushCalleeSavedRegisters() {
   // We need to save pairs of registers
   // We save r19-r30
   const fextl::vector<std::pair<ARMEmitter::XRegister, ARMEmitter::XRegister>> CalleeSaved = {{
-#ifdef _WIN32
-    // Platform register, Just save it twice to make logic easy.
-    {ARMEmitter::XReg::x18, ARMEmitter::XReg::x18},
-#endif
     {ARMEmitter::XReg::x19, ARMEmitter::XReg::x20},
     {ARMEmitter::XReg::x21, ARMEmitter::XReg::x22},
     {ARMEmitter::XReg::x23, ARMEmitter::XReg::x24},
@@ -384,10 +380,6 @@ void Arm64Emitter::PopCalleeSavedRegisters() {
     {ARMEmitter::XReg::x23, ARMEmitter::XReg::x24},
     {ARMEmitter::XReg::x21, ARMEmitter::XReg::x22},
     {ARMEmitter::XReg::x19, ARMEmitter::XReg::x20},
-#ifdef _WIN32
-    // Platform register.
-    {ARMEmitter::XReg::x18, ARMEmitter::XReg::zr},
-#endif
   }};
 
   for (auto &RegPair : CalleeSaved) {