[llvm] [TRI][RISCV] Add methods to get common register class of two registers (PR #118435)

[Pengcheng Wang via llvm-commits]

================
@@ -222,6 +222,25 @@ TargetRegisterInfo::getMinimalPhysRegClass(MCRegister reg, MVT VT) const {
   return BestRC;
 }
 
+const TargetRegisterClass *TargetRegisterInfo::getCommonMinimalPhysRegClass(
----------------
wangpc-pp wrote:

Is it possible to represent default argument value in a template function?

https://github.com/llvm/llvm-project/pull/118435