Address xen0n's comments

Author: heiher

llvm/lib/Target/LoongArch/AsmParser/LoongArchAsmParser.cpp

@@ -1633,6 +1633,9 @@ LoongArchAsmParser::validateTargetOperandClass(MCParsedAsmOperand &AsmOp,
     return Match_Success;
   }
 
+  if (Kind == MCK_GPRNoR0R1 && (Reg == LoongArch::R0 || Reg == LoongArch::R1))
+    return Match_RequiresOpnd2NotR0R1;
+
   return Match_InvalidOperand;
 }
 

llvm/test/MC/LoongArch/Basic/Privilege/invalid.s

@@ -3,9 +3,9 @@
 
 ## csrxchg: rj != 0,1
 csrxchg $a0, $zero, 0
-# ERR: :[[#@LINE-1]]:15: error: invalid operand for instruction
+# ERR: :[[#@LINE-1]]:15: error: must not be $r0 or $r1
 csrxchg $a0, $ra, 0
-# ERR: :[[#@LINE-1]]:15: error: invalid operand for instruction
+# ERR: :[[#@LINE-1]]:15: error: must not be $r0 or $r1
 
 ## LoongArch64 mnemonics
 iocsrrd.d $a0, $a1

llvm/test/MC/LoongArch/lvz/lvz-err.s

@@ -19,10 +19,10 @@ gcsrxchg $a0, $a1, -1
 # CHECK: :[[#@LINE-1]]:20: error: immediate must be an integer in the range [0, 16383]
 
 gcsrxchg $a0, $ra, 1
-# CHECK: :[[#@LINE-1]]:16: error: invalid operand for instruction
+# CHECK: :[[#@LINE-1]]:16: error: must not be $r0 or $r1
 
 gcsrxchg $a0, $zero, 1
-# CHECK: :[[#@LINE-1]]:16: error: invalid operand for instruction
+# CHECK: :[[#@LINE-1]]:16: error: must not be $r0 or $r1
 
 hvcl 32768
 # CHECK: :[[#@LINE-1]]:6: error: immediate must be an integer in the range [0, 32767]