diff --git a/llvm/lib/Target/AArch64/AArch64InstrFormats.td b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
--- a/llvm/lib/Target/AArch64/AArch64InstrFormats.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
@@ -1937,6 +1937,15 @@
   let Inst{4-0}   = Rd;
 }
 
+class ClearAuth<bits<1> data, string asm>
+  : I<(outs GPR64:$Rd), (ins GPR64:$Rn), asm, "\t$Rd", "$Rd = $Rn", []>, Sched<[]> {
+  bits<5> Rd;
+  let Inst{31-11} = 0b110110101100000101000;
+  let Inst{10} = data;
+  let Inst{9-5} = 0b11111;
+  let Inst{4-0} = Rd;
+}
+
 // Base class for the Armv8.4-A 8 and 16-bit flag manipulation instructions
 class BaseFlagManipulation<bit sf, bit sz, dag iops, string asm, string ops>
     : I<(outs), iops, asm, ops, "", []>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -994,8 +994,8 @@
   defm PAC : SignAuth<0b000, 0b010, "pac">;
   defm AUT : SignAuth<0b001, 0b011, "aut">;
 
-  def XPACI : SignAuthZero<0b100, 0b00, "xpaci">;
-  def XPACD : SignAuthZero<0b100, 0b01, "xpacd">;
+  def XPACI : ClearAuth<0, "xpaci">;
+  def XPACD : ClearAuth<1, "xpacd">;
   def PACGA : SignAuthTwoOperand<0b1100, "pacga", null_frag>;
 
   // Combined Instructions