[llvm] [AArch64] Separate PNR into its own Register Class (PR #65306)

[Matthew Devereau via llvm-commits]

================
@@ -4156,6 +4170,10 @@ void AArch64InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
     } else if (AArch64::PNRRegClass.hasSubClassEq(RC)) {
       assert((Subtarget.hasSVE2p1() || Subtarget.hasSME2()) &&
              "Unexpected register load without SVE2p1 or SME2");
+      if (DestReg != AArch64::SP) {
----------------
MDevereau wrote:

I saw it done elsewhere in this function and wanted to be conservative, but yes, it is pointless. Removed.

https://github.com/llvm/llvm-project/pull/65306