diff --git a/llvm/lib/Target/AArch64/AArch64CallingConvention.td b/llvm/lib/Target/AArch64/AArch64CallingConvention.td
index 948b9ddb5df6..66d92100e637 100644
--- a/llvm/lib/Target/AArch64/AArch64CallingConvention.td
+++ b/llvm/lib/Target/AArch64/AArch64CallingConvention.td
@@ -279,6 +279,15 @@ def CSR_AArch64_TLS_Darwin
                            FP,
                            (sequence "Q%u", 0, 31))>;
 
+// We can only handle a register pair with adjacent registers, the register pair
+// should belong to the same class as well. Since the access function on the
+// fast path calls a function that follows CSR_AArch64_TLS_Darwin,
+// CSR_AArch64_CXX_TLS_Darwin should be a subset of CSR_AArch64_TLS_Darwin.
+def CSR_AArch64_CXX_TLS_Darwin
+    : CalleeSavedRegs<(add CSR_AArch64_AAPCS,
+                           (sub (sequence "X%u", 1, 28), X15, X16, X17, X18),
+                           (sequence "D%u", 0, 31))>;
+
 // The ELF stub used for TLS-descriptor access saves every feasible
 // register. Only X0 and LR are clobbered.
 def CSR_AArch64_TLS_ELF
diff --git a/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp b/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
index 1aef31baad20..763b2337de12 100644
--- a/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
@@ -46,6 +46,8 @@ AArch64RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
     return CSR_AArch64_NoRegs_SaveList;
   if (MF->getFunction()->getCallingConv() == CallingConv::AnyReg)
     return CSR_AArch64_AllRegs_SaveList;
+  if (MF->getFunction()->getCallingConv() == CallingConv::CXX_FAST_TLS)
+    return CSR_AArch64_CXX_TLS_Darwin_SaveList;
   else
     return CSR_AArch64_AAPCS_SaveList;
 }
@@ -58,6 +60,8 @@ AArch64RegisterInfo::getCallPreservedMask(const MachineFunction &MF,
     return CSR_AArch64_NoRegs_RegMask;
   if (CC == CallingConv::AnyReg)
     return CSR_AArch64_AllRegs_RegMask;
+  if (CC == CallingConv::CXX_FAST_TLS)
+    return CSR_AArch64_CXX_TLS_Darwin_RegMask;
   else
     return CSR_AArch64_AAPCS_RegMask;
 }
diff --git a/llvm/test/CodeGen/AArch64/cxx-tlscc.ll b/llvm/test/CodeGen/AArch64/cxx-tlscc.ll
new file mode 100644
index 000000000000..39f6c0fbec94
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/cxx-tlscc.ll
@@ -0,0 +1,77 @@
+; RUN: llc < %s -mtriple=aarch64-apple-ios | FileCheck %s
+; RUN: llc < %s -mtriple=aarch64-apple-ios -enable-shrink-wrap=true | FileCheck --check-prefix=CHECK %s
+; Shrink wrapping currently does not kick in because we have a TLS CALL
+; in the entry block and it will clobber the link register.
+
+%struct.S = type { i8 }
+
+@sg = internal thread_local global %struct.S zeroinitializer, align 1
+@__dso_handle = external global i8
+@__tls_guard = internal thread_local unnamed_addr global i1 false
+
+declare %struct.S* @_ZN1SC1Ev(%struct.S* returned)
+declare %struct.S* @_ZN1SD1Ev(%struct.S* returned)
+declare i32 @_tlv_atexit(void (i8*)*, i8*, i8*)
+
+define cxx_fast_tlscc nonnull %struct.S* @_ZTW2sg() {
+  %.b.i = load i1, i1* @__tls_guard, align 1
+  br i1 %.b.i, label %__tls_init.exit, label %init.i
+
+init.i:
+  store i1 true, i1* @__tls_guard, align 1
+  %call.i.i = tail call %struct.S* @_ZN1SC1Ev(%struct.S* nonnull @sg)
+  %1 = tail call i32 @_tlv_atexit(void (i8*)* nonnull bitcast (%struct.S* (%struct.S*)* @_ZN1SD1Ev to void (i8*)*), i8* nonnull getelementptr inbounds (%struct.S, %struct.S* @sg, i64 0, i32 0), i8* nonnull @__dso_handle)
+  br label %__tls_init.exit
+
+__tls_init.exit:
+  ret %struct.S* @sg
+}
+
+; CHECK-LABEL: _ZTW2sg
+; CHECK-DAG: stp d31, d30
+; CHECK-DAG: stp d29, d28
+; CHECK-DAG: stp d27, d26
+; CHECK-DAG: stp d25, d24
+; CHECK-DAG: stp d23, d22
+; CHECK-DAG: stp d21, d20
+; CHECK-DAG: stp d19, d18
+; CHECK-DAG: stp d17, d16
+; CHECK-DAG: stp d7, d6
+; CHECK-DAG: stp d5, d4
+; CHECK-DAG: stp d3, d2
+; CHECK-DAG: stp d1, d0
+; CHECK-DAG: stp x20, x19
+; CHECK-DAG: stp x14, x13
+; CHECK-DAG: stp x12, x11
+; CHECK-DAG: stp x10, x9
+; CHECK-DAG: stp x8, x7
+; CHECK-DAG: stp x6, x5
+; CHECK-DAG: stp x4, x3
+; CHECK-DAG: stp x2, x1
+; CHECK-DAG: stp x29, x30
+; CHECK: blr
+; CHECK: tbnz w{{.*}}, #0, [[BB_end:.?LBB0_[0-9]+]]
+; CHECK: blr
+; CHECK: tlv_atexit
+; CHECK: [[BB_end]]:
+; CHECK: blr
+; CHECK-DAG: ldp x2, x1
+; CHECK-DAG: ldp x4, x3
+; CHECK-DAG: ldp x6, x5
+; CHECK-DAG: ldp x8, x7
+; CHECK-DAG: ldp x10, x9
+; CHECK-DAG: ldp x12, x11
+; CHECK-DAG: ldp x14, x13
+; CHECK-DAG: ldp x20, x19
+; CHECK-DAG: ldp d1, d0
+; CHECK-DAG: ldp d3, d2
+; CHECK-DAG: ldp d5, d4
+; CHECK-DAG: ldp d7, d6
+; CHECK-DAG: ldp d17, d16
+; CHECK-DAG: ldp d19, d18
+; CHECK-DAG: ldp d21, d20
+; CHECK-DAG: ldp d23, d22
+; CHECK-DAG: ldp d25, d24
+; CHECK-DAG: ldp d27, d26
+; CHECK-DAG: ldp d29, d28
+; CHECK-DAG: ldp d31, d30