Index: llvm/trunk/lib/Target/AArch64/AArch64SystemOperands.td
===================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64SystemOperands.td
+++ llvm/trunk/lib/Target/AArch64/AArch64SystemOperands.td
@@ -322,6 +322,9 @@
 def : ROSysReg<"PMCEID1_EL0",        0b11, 0b011, 0b1001, 0b1100, 0b111>;
 def : ROSysReg<"MIDR_EL1",           0b11, 0b000, 0b0000, 0b0000, 0b000>;
 def : ROSysReg<"CCSIDR_EL1",         0b11, 0b001, 0b0000, 0b0000, 0b000>;
+def : ROSysReg<"CCSIDR2_EL1",        0b11, 0b001, 0b0000, 0b0000, 0b010> {
+  let Requires = [{ {AArch64::HasV8_3aOps} }];
+}
 def : ROSysReg<"CLIDR_EL1",          0b11, 0b001, 0b0000, 0b0000, 0b001>;
 def : ROSysReg<"CTR_EL0",            0b11, 0b011, 0b0000, 0b0000, 0b001>;
 def : ROSysReg<"MPIDR_EL1",          0b11, 0b000, 0b0000, 0b0000, 0b101>;
Index: llvm/trunk/test/MC/AArch64/arm64-system-encoding.s
===================================================================
--- llvm/trunk/test/MC/AArch64/arm64-system-encoding.s
+++ llvm/trunk/test/MC/AArch64/arm64-system-encoding.s
@@ -1,4 +1,5 @@
 ; RUN: not llvm-mc -triple arm64-apple-darwin -show-encoding < %s 2> %t | FileCheck %s
+; RUN: not llvm-mc -triple arm64-apple-darwin -mattr=+v8.3a -show-encoding < %s 2> %t | FileCheck %s --check-prefix=CHECK-V83
 ; RUN: FileCheck --check-prefix=CHECK-ERRORS < %t %s
 
 foo:
@@ -233,6 +234,7 @@
   mrs x3, AMAIR_EL3
   mrs x3, CCSIDR_EL1
   mrs x3, CLIDR_EL1
+  mrs x3, CCSIDR2_EL1
   mrs x3, CNTFRQ_EL0
   mrs x3, CNTHCTL_EL2
   mrs x3, CNTHP_CTL_EL2
@@ -418,6 +420,7 @@
 ; CHECK: mrs x3, AMAIR_EL3              ; encoding: [0x03,0xa3,0x3e,0xd5]
 ; CHECK: mrs x3, CCSIDR_EL1             ; encoding: [0x03,0x00,0x39,0xd5]
 ; CHECK: mrs x3, CLIDR_EL1              ; encoding: [0x23,0x00,0x39,0xd5]
+; CHECK-V83: mrs x3, CCSIDR2_EL1        ; encoding: [0x43,0x00,0x39,0xd5]
 ; CHECK: mrs x3, CNTFRQ_EL0             ; encoding: [0x03,0xe0,0x3b,0xd5]
 ; CHECK: mrs x3, CNTHCTL_EL2            ; encoding: [0x03,0xe1,0x3c,0xd5]
 ; CHECK: mrs x3, CNTHP_CTL_EL2          ; encoding: [0x23,0xe2,0x3c,0xd5]
Index: llvm/trunk/test/MC/AArch64/basic-a64-diagnostics.s
===================================================================
--- llvm/trunk/test/MC/AArch64/basic-a64-diagnostics.s
+++ llvm/trunk/test/MC/AArch64/basic-a64-diagnostics.s
@@ -3504,6 +3504,7 @@
         msr MIDR_EL1, x12
         msr CCSIDR_EL1, x12
         msr CLIDR_EL1, x12
+        msr CCSIDR2_EL1, x12
         msr CTR_EL0, x12
         msr MPIDR_EL1, x12
         msr REVIDR_EL1, x12
@@ -3572,6 +3573,9 @@
 // CHECK-ERROR-NEXT:         msr CLIDR_EL1, x12
 // CHECK-ERROR-NEXT:             ^
 // CHECK-ERROR-NEXT: error: expected writable system register or pstate
+// CHECK-ERROR-NEXT:         msr CCSIDR2_EL1, x12
+// CHECK-ERROR-NEXT:             ^
+// CHECK-ERROR-NEXT: error: expected writable system register or pstate
 // CHECK-ERROR-NEXT:         msr CTR_EL0, x12
 // CHECK-ERROR-NEXT:             ^
 // CHECK-ERROR-NEXT: error: expected writable system register or pstate
Index: llvm/trunk/test/MC/Disassembler/AArch64/basic-a64-instructions.txt
===================================================================
--- llvm/trunk/test/MC/Disassembler/AArch64/basic-a64-instructions.txt
+++ llvm/trunk/test/MC/Disassembler/AArch64/basic-a64-instructions.txt
@@ -1,6 +1,7 @@
 # RUN: llvm-mc -triple=aarch64 -mattr=+fp-armv8 -disassemble < %s | FileCheck %s
 # RUN: llvm-mc -triple=arm64 -mattr=+fp-armv8 -disassemble < %s | FileCheck %s
 # RUN: llvm-mc -triple=arm64 -mattr=+fp-armv8,+fullfp16 -disassemble < %s | FileCheck %s --check-prefix=CHECK --check-prefix=FP16
+# RUN: llvm-mc -triple=arm64 -mattr=+v8.3a -disassemble < %s | FileCheck %s --check-prefix=CHECK-V83
 
 #------------------------------------------------------------------------------
 # Add/sub (immediate)
@@ -3493,6 +3494,7 @@
 # CHECK: mrs      x9, {{midr_el1|MIDR_EL1}}
 # CHECK: mrs      x9, {{ccsidr_el1|CCSIDR_EL1}}
 # CHECK: mrs      x9, {{csselr_el1|CSSELR_EL1}}
+# CHECK-V83: mrs  x9, {{ccsidr2_el1|CCSIDR2_EL1}}
 # CHECK: mrs      x9, {{vpidr_el2|VPIDR_EL2}}
 # CHECK: mrs      x9, {{clidr_el1|CLIDR_EL1}}
 # CHECK: mrs      x9, {{ctr_el0|CTR_EL0}}
@@ -4048,6 +4050,7 @@
 0x9 0x0 0x38 0xd5
 0x9 0x0 0x39 0xd5
 0x9 0x0 0x3a 0xd5
+0x49 0x0 0x39 0xd5
 0x9 0x0 0x3c 0xd5
 0x29 0x0 0x39 0xd5
 0x29 0x0 0x3b 0xd5