Index: clang/lib/Driver/ToolChain.cpp
===================================================================
--- clang/lib/Driver/ToolChain.cpp
+++ clang/lib/Driver/ToolChain.cpp
@@ -1063,9 +1063,9 @@
       getTriple().isAArch64())
     Res |= SanitizerKind::CFIICall;
   if (getTriple().getArch() == llvm::Triple::x86_64 ||
-      getTriple().isAArch64() || getTriple().isRISCV())
+      getTriple().isAArch64(64) || getTriple().isRISCV())
     Res |= SanitizerKind::ShadowCallStack;
-  if (getTriple().isAArch64())
+  if (getTriple().isAArch64(64))
     Res |= SanitizerKind::MemTag;
   return Res;
 }
Index: clang/test/Driver/frame-pointer-elim.c
===================================================================
--- clang/test/Driver/frame-pointer-elim.c
+++ clang/test/Driver/frame-pointer-elim.c
@@ -97,6 +97,8 @@
 // RUN:   FileCheck --check-prefix=KEEP-NON-LEAF %s
 // RUN: %clang -### -target x86_64-scei-ps4 -S -O2 %s 2>&1 | \
 // RUN:   FileCheck --check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang -### -target aarch64-apple-darwin -arch arm64_32 -S %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=KEEP-NON-LEAF %s
 
 // RUN: %clang -### -target powerpc64 -S %s 2>&1 | \
 // RUN:   FileCheck --check-prefix=KEEP-ALL %s
Index: llvm/include/llvm/ADT/Triple.h
===================================================================
--- llvm/include/llvm/ADT/Triple.h
+++ llvm/include/llvm/ADT/Triple.h
@@ -714,7 +714,17 @@
 
   /// Tests whether the target is AArch64 (little and big endian).
   bool isAArch64() const {
-    return getArch() == Triple::aarch64 || getArch() == Triple::aarch64_be;
+    return getArch() == Triple::aarch64 || getArch() == Triple::aarch64_be ||
+           getArch() == Triple::aarch64_32;
+  }
+
+  /// Tests whether the target is AArch64 and pointers are the size specified by
+  /// \p PointerWidth.
+  bool isAArch64(int PointerWidth) const {
+    assert(PointerWidth == 64 || PointerWidth == 32);
+    if (!isAArch64())
+      return false;
+    return isArch64Bit() ? PointerWidth == 64 : PointerWidth == 32;
   }
 
   /// Tests whether the target is MIPS 32-bit (little and big endian).
Index: llvm/lib/BinaryFormat/MachO.cpp
===================================================================
--- llvm/lib/BinaryFormat/MachO.cpp
+++ llvm/lib/BinaryFormat/MachO.cpp
@@ -55,7 +55,7 @@
 }
 
 static MachO::CPUSubTypeARM64 getARM64SubType(const Triple &T) {
-  assert(T.isAArch64() || T.getArch() == Triple::aarch64_32);
+  assert(T.isAArch64());
   if (T.isArch32Bit())
     return (MachO::CPUSubTypeARM64)MachO::CPU_SUBTYPE_ARM64_32_V8;
   if (T.getArchName() == "arm64e")
@@ -84,9 +84,7 @@
   if (T.isARM() || T.isThumb())
     return MachO::CPU_TYPE_ARM;
   if (T.isAArch64())
-    return MachO::CPU_TYPE_ARM64;
-  if (T.getArch() == Triple::aarch64_32)
-    return MachO::CPU_TYPE_ARM64_32;
+    return T.isArch32Bit() ? MachO::CPU_TYPE_ARM64_32 : MachO::CPU_TYPE_ARM64;
   if (T.getArch() == Triple::ppc)
     return MachO::CPU_TYPE_POWERPC;
   if (T.getArch() == Triple::ppc64)