Index: clang/include/clang/Basic/DiagnosticDriverKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -368,6 +368,9 @@
 def err_drv_ropi_incompatible_with_cxx : Error<
   "ROPI is not compatible with c++">;
 
+def err_stack_tagging_requires_hardware_feature : Error<
+  "'-fsanitize=memtag' requires the v8.5A Memory Tagging Extension (+memtag)">;
+
 def warn_target_unsupported_nan2008 : Warning<
   "ignoring '-mnan=2008' option because the '%0' architecture does not support it">,
   InGroup<UnsupportedNan>;
Index: clang/include/clang/Driver/SanitizerArgs.h
===================================================================
--- clang/include/clang/Driver/SanitizerArgs.h
+++ clang/include/clang/Driver/SanitizerArgs.h
@@ -63,6 +63,7 @@
   bool needsHwasanRt() const {
     return Sanitizers.has(SanitizerKind::HWAddress);
   }
+  bool needsMemtag() const { return Sanitizers.has(SanitizerKind::MemTag); }
   bool needsTsanRt() const { return Sanitizers.has(SanitizerKind::Thread); }
   bool needsMsanRt() const { return Sanitizers.has(SanitizerKind::Memory); }
   bool needsFuzzer() const { return Sanitizers.has(SanitizerKind::Fuzzer); }
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -1564,7 +1564,8 @@
 
 void Clang::AddAArch64TargetArgs(const ArgList &Args,
                                  ArgStringList &CmdArgs) const {
-  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
+  const ToolChain &TC = getToolChain();
+  const llvm::Triple &Triple = TC.getEffectiveTriple();
 
   if (!Args.hasFlag(options::OPT_mred_zone, options::OPT_mno_red_zone, true) ||
       Args.hasArg(options::OPT_mkernel) ||
@@ -1601,11 +1602,9 @@
   }
 
   // Enable/disable return address signing and indirect branch targets.
+  const Driver &D = TC.getDriver();
   if (Arg *A = Args.getLastArg(options::OPT_msign_return_address_EQ,
                                options::OPT_mbranch_protection_EQ)) {
-
-    const Driver &D = getToolChain().getDriver();
-
     StringRef Scope, Key;
     bool IndirectBranches;
 
@@ -1628,6 +1627,12 @@
     if (IndirectBranches)
       CmdArgs.push_back("-mbranch-target-enforce");
   }
+
+  if (TC.getSanitizerArgs().needsMemtag()) {
+    if (std::find(CmdArgs.begin(), CmdArgs.end(), StringRef("+mte")) == CmdArgs.end()) {
+      D.Diag(diag::err_stack_tagging_requires_hardware_feature);
+    }
+  }
 }
 
 void Clang::AddMIPSTargetArgs(const ArgList &Args,
Index: clang/test/Driver/fsanitize.c
===================================================================
--- clang/test/Driver/fsanitize.c
+++ clang/test/Driver/fsanitize.c
@@ -191,6 +191,13 @@
 // RUN: %clang -target x86_64-linux-android -fsanitize=memtag -fno-rtti %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANMT-BAD-ARCH
 // CHECK-SANMT-BAD-ARCH: unsupported option '-fsanitize=memtag' for target
 
+// RUN: %clang -target aarch64-linux -fsanitize=memtag -march=armv8-a+memtag %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANMT-MT
+// CHECK-SANMT-MT: "-target-feature" "+mte"
+// CHECK-SANMT-MT-SAME: "-fsanitize=memtag"
+
+// RUN: %clang -target aarch64-linux -fsanitize=memtag %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANMT-NOMT
+// CHECK-SANMT-NOMT: '-fsanitize=memtag' requires the v8.5A Memory Tagging Extension (+memtag)
+
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-use-after-scope %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-USE-AFTER-SCOPE
 // RUN: %clang_cl --target=x86_64-windows -fsanitize=address -fsanitize-address-use-after-scope -### -- %s 2>&1 | FileCheck %s --check-prefix=CHECK-USE-AFTER-SCOPE
 // CHECK-USE-AFTER-SCOPE: -cc1{{.*}}-fsanitize-address-use-after-scope