diff --git a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
--- a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -3676,6 +3676,9 @@
     {"the", {AArch64::FeatureTHE}},
     {"d128", {AArch64::FeatureD128}},
     {"lse128", {AArch64::FeatureLSE128}},
+    {"ite", {AArch64::FeatureITE}},
+    {"cssc", {AArch64::FeatureCSSC}},
+    {"rcpc3", {AArch64::FeatureRCPC3}},
     // FIXME: Unsupported extensions
     {"lor", {}},
     {"rdma", {}},
diff --git a/llvm/test/MC/AArch64/directive-arch_extension-negative.s b/llvm/test/MC/AArch64/directive-arch_extension-negative.s
--- a/llvm/test/MC/AArch64/directive-arch_extension-negative.s
+++ b/llvm/test/MC/AArch64/directive-arch_extension-negative.s
@@ -1,6 +1,6 @@
 // RUN: not llvm-mc -triple aarch64 \
 // RUN: -mattr=+crc,+sm4,+sha3,+sha2,+aes,+fp,+neon,+ras,+lse,+predres,+ccdp,+mte,+tlb-rmi,+pan-rwv,+ccpp,+rcpc,+ls64,+flagm,+hbc,+mops \
-// RUN: -mattr=+rcpc3,+lse128,+d128,+the,+rasv2 \
+// RUN: -mattr=+rcpc3,+lse128,+d128,+the,+rasv2,+ite,+cssc,+specres2 \
 // RUN: -filetype asm -o - %s 2>&1 | FileCheck %s
 
 .arch_extension axp64
@@ -70,6 +70,13 @@
 // CHECK: [[@LINE-1]]:1: error: instruction requires: lse
 // CHECK-NEXT: casa w5, w7, [x20]
 
+swpp x0, x2, [x3]
+// CHECK-NOT: [[@LINE-1]]:1: error: instruction requires: lse128
+.arch_extension nolse128
+swpp x0, x2, [x3]
+// CHECK: [[@LINE-1]]:1: error: instruction requires: lse128
+// CHECK-NEXT: swpp x0, x2, [x3]
+
 cfp rctx, x0
 // CHECK-NOT: [[@LINE-1]]:5: error: CFPRCTX requires: predres
 .arch_extension nopredres
@@ -77,6 +84,13 @@
 // CHECK: [[@LINE-1]]:5: error: CFPRCTX requires: predres
 // CHECK-NEXT: cfp rctx, x0
 
+cosp rctx, x0
+// CHECK-NOT: [[@LINE-1]]:6: error: COSP requires: predres2
+.arch_extension nopredres2
+cosp rctx, x0
+// CHECK: [[@LINE-1]]:6: error: COSP requires: predres2
+// CHECK-NEXT: cosp rctx, x0
+
 dc cvadp, x7
 // CHECK-NOT: [[@LINE-1]]:4: error: DC CVADP requires: ccdp
 .arch_extension noccdp
@@ -119,6 +133,13 @@
 // CHECK: [[@LINE-1]]:1: error: instruction requires: rcpc
 // CHECK-NEXT: ldapr x0, [x1]
 
+stilp w24, w0, [x16, #-8]!
+// CHECK-NOT: [[@LINE-1]]:1: error: instruction requires: rcpc3
+.arch_extension norcpc3
+stilp w24, w0, [x16, #-8]!
+// CHECK: [[@LINE-1]]:1: error: instruction requires: rcpc3
+// CHECK-NEXT: stilp w24, w0, [x16, #-8]!
+
 ld64b x0, [x13]
 // CHECK-NOT: [[@LINE-1]]:1: error: instruction requires: ls64
 .arch_extension nols64
@@ -169,6 +190,20 @@
 // CHECK: [[@LINE-1]]:1: error: instruction requires: the
 // CHECK-NEXT: rcwswp x0, x1, [x2]
 
+trcit x0
+// CHECK-NOT: [[@LINE-1]]:1: error: instruction requires: ite
+.arch_extension noite
+trcit x0
+// CHECK: [[@LINE-1]]:1: error: instruction requires: ite
+// CHECK-NEXT: trcit x0
+
+umax x0, x1, x2
+// CHECK-NOT: [[@LINE-1]]:1: error: instruction requires: cssc
+.arch_extension nocssc
+umax x0, x1, x2
+// CHECK: [[@LINE-1]]:1: error: instruction requires: cssc
+// CHECK-NEXT: umax x0, x1, x2
+
 mrs x0, ERXGSR_EL1
 // CHECK-NOT: [[@LINE-1]]:9: error: expected readable system register
 .arch_extension norasv2
diff --git a/llvm/test/MC/AArch64/directive-arch_extension.s b/llvm/test/MC/AArch64/directive-arch_extension.s
--- a/llvm/test/MC/AArch64/directive-arch_extension.s
+++ b/llvm/test/MC/AArch64/directive-arch_extension.s
@@ -36,10 +36,18 @@
 casa w5, w7, [x20]
 // CHECK: casa w5, w7, [x20]
 
+.arch_extension lse128
+swpp x0, x2, [x3]
+// CHECK: swpp x0, x2, [x3]
+
 .arch_extension predres
 cfp rctx, x0
 // CHECK: cfp rctx, x0
 
+.arch_extension predres2
+cosp rctx, x0
+// CHECK: cosp rctx, x0
+
 .arch_extension ccdp
 dc cvadp, x7
 // CHECK: dc cvadp, x7
@@ -72,6 +80,10 @@
 ldapr x0, [x1]
 // CHECK: ldapr x0, [x1]
 
+.arch_extension rcpc3
+stilp   w24, w0, [x16, #-8]!
+// CHECK: stilp   w24, w0, [x16, #-8]!
+
 .arch_extension ls64
 ld64b x0, [x13]
 // CHECK: ld64b x0, [x13]
@@ -108,3 +120,11 @@
 .arch_extension rasv2
 mrs x0, ERXGSR_EL1
 // CHECK: mrs x0, ERXGSR_EL1
+
+.arch_extension ite
+trcit x0
+// CHECK: trcit x0
+
+.arch_extension cssc
+umax x0, x1, x2
+// CHECK: umax x0, x1, x2