Index: lib/Basic/Targets.cpp
===================================================================
--- lib/Basic/Targets.cpp
+++ lib/Basic/Targets.cpp
@@ -3399,6 +3399,7 @@
   };
 
   unsigned FPU;
+  unsigned CRC;
   unsigned Crypto;
   static const Builtin::Info BuiltinInfo[];
 
@@ -3475,6 +3476,9 @@
       Builder.defineMacro("__ARM_NEON_FP", "7");
     }
 
+    if (CRC)
+      Builder.defineMacro("__ARM_FEATURE_CRC32");
+
     if (Crypto) {
       Builder.defineMacro("__ARM_FEATURE_CRYPTO");
     }
@@ -3498,10 +3502,13 @@
   bool handleTargetFeatures(std::vector<std::string> &Features,
                             DiagnosticsEngine &Diags) override {
     FPU = FPUMode;
+    CRC = 0;
     Crypto = 0;
     for (unsigned i = 0, e = Features.size(); i != e; ++i) {
       if (Features[i] == "+neon")
         FPU = NeonMode;
+      if (Features[i] == "+crc")
+        CRC = 1;
       if (Features[i] == "+crypto")
         Crypto = 1;
     }
@@ -4492,6 +4499,7 @@
   };
 
   unsigned FPU;
+  unsigned CRC;
   unsigned Crypto;
 
   static const Builtin::Info BuiltinInfo[];
@@ -4589,6 +4597,9 @@
       Builder.defineMacro("__ARM_NEON_FP", "7");
     }
 
+    if (CRC)
+      Builder.defineMacro("__ARM_FEATURE_CRC32");
+
     if (Crypto)
       Builder.defineMacro("__ARM_FEATURE_CRYPTO");
   }
@@ -4608,10 +4619,13 @@
   bool handleTargetFeatures(std::vector<std::string> &Features,
                             DiagnosticsEngine &Diags) override {
     FPU = FPUMode;
+    CRC = 0;
     Crypto = 0;
     for (unsigned i = 0, e = Features.size(); i != e; ++i) {
       if (Features[i] == "+neon")
         FPU = NeonMode;
+      if (Features[i] == "+crc")
+        CRC = 1;
       if (Features[i] == "+crypto")
         Crypto = 1;
     }
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -1540,6 +1540,15 @@
     Features.push_back("-crypto");
     Features.push_back("-neon");
   }
+
+  // En/disable crc
+  if (Arg *A = Args.getLastArg(options::OPT_mcrc,
+                               options::OPT_mnocrc)) {
+    if (A->getOption().matches(options::OPT_mcrc))
+      Features.push_back("+crc");
+    else
+      Features.push_back("-crc");
+  }
 }
 
 static void getTargetFeatures(const Driver &D, const llvm::Triple &Triple,
Index: test/Preprocessor/aarch64-target-features.c
===================================================================
--- test/Preprocessor/aarch64-target-features.c
+++ test/Preprocessor/aarch64-target-features.c
@@ -10,6 +10,7 @@
 // CHECK: __ARM_ARCH_PROFILE 'A'
 // CHECK-NOT: __ARM_FEATURE_BIG_ENDIAN
 // CHECK: __ARM_FEATURE_CLZ 1
+// CHECK-NOT: __ARM_FEATURE_CRC32 1
 // CHECK-NOT: __ARM_FEATURE_CRYPTO 1
 // CHECK: __ARM_FEATURE_DIV 1
 // CHECK: __ARM_FEATURE_FMA 1
@@ -27,6 +28,10 @@
 // RUN: %clang -target aarch64-none-linux-gnu -mfpu=crypto-neon-fp-armv8 -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-CRYPTO %s
 // CHECK-CRYPTO: __ARM_FEATURE_CRYPTO 1
 
+// RUN: %clang -target aarch64-none-linux-gnu -mcrc -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-CRC32 %s
+// RUN: %clang -target arm64-none-linux-gnu -mcrc -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-CRC32 %s
+// CHECK-CRC32: __ARM_FEATURE_CRC32 1
+
 // RUN: %clang -target aarch64-none-linux-gnu -ffast-math -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-FASTMATH %s
 // CHECK-FASTMATH: __ARM_FP_FAST 1