[llvm] [Mips] Introduce ABI-specific register names and accessors (PR #224284)

[Jiaxun Yang via llvm-commits]

================
@@ -4102,7 +4101,7 @@ MipsTargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
       llvm_unreachable("sret virtual register not created in the entry block");
     SDValue Val =
         DAG.getCopyFromReg(Chain, DL, Reg, getPointerTy(DAG.getDataLayout()));
-    unsigned V0 = ABI.IsN64() ? Mips::V0_64 : Mips::V0;
+    unsigned V0 = ABI.getReturnReg(0, ABI.ArePtrs64bit());
----------------
FlyGoat wrote:

Ditto

https://github.com/llvm/llvm-project/pull/224284