diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 68a199857328643d8b836975cfa706a2d79082e6..9f0fb902f3895153bd730ed8b82a75738e5d3aa7 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -4536,7 +4536,8 @@ class ARMTargetInfo : public TargetInfo {
   }
 
   bool supportsThumb2() const {
-    return CPUAttr.equals("6T2") || ArchVersion >= 7;
+    return CPUAttr.equals("6T2") ||
+           (ArchVersion >= 7 && !CPUAttr.equals("8M_BASE"));
   }
 
   StringRef getCPUAttr() const {
@@ -4563,6 +4564,10 @@ class ARMTargetInfo : public TargetInfo {
       return "8_1A";
     case llvm::ARM::AK_ARMV8_2A:
       return "8_2A";
+    case llvm::ARM::AK_ARMV8MBaseline:
+      return "8M_BASE";
+    case llvm::ARM::AK_ARMV8MMainline:
+      return "8M_MAIN";
     }
   }
 
@@ -4852,13 +4857,14 @@ public:
 
     // __ARM_ARCH_ISA_ARM is defined to 1 if the core supports the ARM ISA.  It
     // is not defined for the M-profile.
-    // NOTE that the deffault profile is assumed to be 'A'
-    if (CPUProfile.empty() || CPUProfile != "M")
+    // NOTE that the default profile is assumed to be 'A'
+    if (CPUProfile.empty() || ArchProfile != llvm::ARM::PK_M)
       Builder.defineMacro("__ARM_ARCH_ISA_ARM", "1");
 
-    // __ARM_ARCH_ISA_THUMB is defined to 1 if the core supporst the original
-    // Thumb ISA (including v6-M).  It is set to 2 if the core supports the
-    // Thumb-2 ISA as found in the v6T2 architecture and all v7 architecture.
+    // __ARM_ARCH_ISA_THUMB is defined to 1 if the core supports the original
+    // Thumb ISA (including v6-M and v8-M Baseline).  It is set to 2 if the
+    // core supports the Thumb-2 ISA as found in the v6T2 architecture and all
+    // v7 and v8 architectures excluding v8-M Baseline.
     if (supportsThumb2())
       Builder.defineMacro("__ARM_ARCH_ISA_THUMB", "2");
     else if (supportsThumb())
@@ -4978,7 +4984,7 @@ public:
     Builder.defineMacro("__ARM_SIZEOF_MINIMAL_ENUM",
                         Opts.ShortEnums ? "1" : "4");
 
-    if (ArchVersion >= 6 && CPUAttr != "6M") {
+    if (ArchVersion >= 6 && CPUAttr != "6M" && CPUAttr != "8M_BASE") {
       Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1");
       Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2");
       Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4");
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 6e97183da1c4f64cfb9b0ffc601b1d7454aca90d..285a8221f0b5ef768cbde7961e9a4abf16927dd1 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -963,6 +963,10 @@ static void getARMTargetFeatures(const ToolChain &TC,
       // No v6M core supports unaligned memory access (v6M ARM ARM A3.2).
       if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v6m)
         D.Diag(diag::err_target_unsupported_unaligned) << "v6m";
+      // v8M Baseline follows on from v6M, so doesn't support unaligned memory
+      // access either.
+      else if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v8m_baseline)
+        D.Diag(diag::err_target_unsupported_unaligned) << "v8m.base";
     } else
       Features.push_back("+strict-align");
   } else {
diff --git a/test/Driver/arm-alignment.c b/test/Driver/arm-alignment.c
index 3e21652039563506c001b8cc0bac6dcbd7023e6a..e0b4946d0a4b165fa6f435f208caca3966c6c039 100644
--- a/test/Driver/arm-alignment.c
+++ b/test/Driver/arm-alignment.c
@@ -83,11 +83,13 @@
 // CHECK-ALIGNED-ARM: "-target-feature" "+strict-align"
 // CHECK-ALIGNED-AARCH64: "-target-feature" "+strict-align"
 
-// Make sure that v6M cores always trigger the unsupported aligned accesses error
-// for all supported architecture triples.
+// Make sure that v6M cores and v8M Baseline always trigger the unsupported
+// aligned accesses error for all supported architecture triples.
 // RUN: not %clang -c -target thumbv6m-none-gnueabi -mcpu=cortex-m0 -munaligned-access %s 2>&1 | \
 // RUN:   FileCheck --check-prefix CHECK-UNALIGN-NOT-SUPPORTED %s
 // RUN: not %clang -c -target thumb-none-gnueabi -mcpu=cortex-m0 -munaligned-access %s 2>&1 | \
 // RUN:   FileCheck --check-prefix CHECK-UNALIGN-NOT-SUPPORTED %s
+// RUN: not %clang -c -target thumbv8m.base-none-gnueabi -munaligned-access %s 2>&1 | \
+// RUN:   FileCheck --check-prefix CHECK-UNALIGN-NOT-SUPPORTED %s
 
-// CHECK-UNALIGN-NOT-SUPPORTED: error: the v6m sub-architecture does not support unaligned accesses
+// CHECK-UNALIGN-NOT-SUPPORTED: error: the {{.*}} sub-architecture does not support unaligned accesses
diff --git a/test/Driver/arm-cortex-cpus.c b/test/Driver/arm-cortex-cpus.c
index fdacfb8fbe7ae9d34ecc4446436c5998ab3ffc8e..a882c8acadcd9f4948103c1b7f915b25b4e1e84e 100644
--- a/test/Driver/arm-cortex-cpus.c
+++ b/test/Driver/arm-cortex-cpus.c
@@ -273,6 +273,24 @@
 // CHECK-CORTEX-A53-FP16: "-cc1" {{.*}}"-target-cpu" "cortex-a53" {{.*}}"-target-feature" "+fullfp16"
 // CHECK-CORTEX-A53-NOFP16: "-cc1" {{.*}}"-target-cpu" "cortex-a53" {{.*}}"-target-feature" "-fullfp16"
 
+// RUN: %clang -target armv8m.base %s -### -c 2>&1 | FileCheck %s --check-prefix=V8M_BASELINE
+// RUN: %clang -target arm -march=armv8-m.base %s -### -c 2>&1 | FileCheck %s --check-prefix=V8M_BASELINE
+// RUN: %clang -target arm -march=armv8m.base %s -### -c 2>&1 | FileCheck %s --check-prefix=V8M_BASELINE
+// RUN: %clang -target armv8m.base -mbig-endian %s -### -c 2>&1 | FileCheck %s --check-prefix=EBV8M_BASELINE
+// RUN: %clang -target arm -march=armv8-m.base -mbig-endian %s -### -c 2>&1 | FileCheck %s --check-prefix=EBV8M_BASELINE
+// RUN: %clang -target arm -march=armv8m.base -mbig-endian %s -### -c 2>&1 | FileCheck %s --check-prefix=EBV8M_BASELINE
+// V8M_BASELINE: "-cc1"{{.*}} "-triple" "thumbv8m.base-{{.*}} "-target-cpu" "generic"
+// EBV8M_BASELINE: "-cc1"{{.*}} "-triple" "thumbebv8m.base-{{.*}} "-target-cpu" "generic"
+
+// RUN: %clang -target armv8m.main %s -### -c 2>&1 | FileCheck %s --check-prefix=V8M_MAINLINE
+// RUN: %clang -target arm -march=armv8-m.main %s -### -c 2>&1 | FileCheck %s --check-prefix=V8M_MAINLINE
+// RUN: %clang -target arm -march=armv8m.main %s -### -c 2>&1 | FileCheck %s --check-prefix=V8M_MAINLINE
+// RUN: %clang -target armv8m.main -mbig-endian %s -### -c 2>&1 | FileCheck %s --check-prefix=EBV8M_MAINLINE
+// RUN: %clang -target arm -march=armv8-m.main -mbig-endian %s -### -c 2>&1 | FileCheck %s --check-prefix=EBV8M_MAINLINE
+// RUN: %clang -target arm -march=armv8m.main -mbig-endian %s -### -c 2>&1 | FileCheck %s --check-prefix=EBV8M_MAINLINE
+// V8M_MAINLINE: "-cc1"{{.*}} "-triple" "thumbv8m.main-{{.*}} "-target-cpu" "generic"
+// EBV8M_MAINLINE: "-cc1"{{.*}} "-triple" "thumbebv8m.main-{{.*}} "-target-cpu" "generic"
+
 // ================== Check that a bogus architecture gives an error
 // RUN: %clang -target arm -march=armbogusv6 -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-BOGUS %s
 // CHECK-BOGUS: error: {{.*}} does not support '-march=armbogusv6' 
diff --git a/test/Driver/arm-features.c b/test/Driver/arm-features.c
index eb197da935a03147d26d641f55828b7f11d9686b..74cedf3bd83b760aff69aa2fb5b87e69136c3e37 100644
--- a/test/Driver/arm-features.c
+++ b/test/Driver/arm-features.c
@@ -4,6 +4,9 @@
 // RUN: %clang -target arm-none-none-eabi -mcpu=generic+crypto -march=armv8a -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-CRYPTO %s
 // RUN: %clang -target arm-none-none-eabi -mcpu=generic -march=armv8a+crypto -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-CRYPTO %s
 // CHECK-CRYPTO: "-cc1"{{.*}} "-triple" "armv8-{{.*}} "-target-cpu" "generic"{{.*}} "-target-feature" "+crypto"
+// RUN: %clang -target arm-none-none-eabi -mcpu=generic+dsp -march=armv8m.main -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-DSP %s
+// RUN: %clang -target arm-none-none-eabi -mcpu=generic -march=armv8m.main+dsp -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-DSP %s
+// CHECK-DSP: "-cc1"{{.*}} "-triple" "thumbv8m.main-{{.*}} "-target-cpu" "generic"{{.*}} "-target-feature" "+dsp"
 
 // RUN: %clang -target arm-none-none-eabi -mcpu=generic+nocrc -march=armv8a -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-NOCRC %s
 // RUN: %clang -target arm-none-none-eabi -mcpu=generic -march=armv8a+nocrc -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-NOCRC %s
@@ -11,3 +14,6 @@
 // RUN: %clang -target arm-none-none-eabi -mcpu=generic+nocrypto -march=armv8a -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-NOCRYPTO %s
 // RUN: %clang -target arm-none-none-eabi -mcpu=generic -march=armv8a+nocrypto -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-NOCRYPTO %s
 // CHECK-NOCRYPTO: "-cc1"{{.*}} "-triple" "armv8-{{.*}} "-target-cpu" "generic"{{.*}} "-target-feature" "-crypto"
+// RUN: %clang -target arm-none-none-eabi -mcpu=generic+nodsp -march=armv8m.main -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-NODSP %s
+// RUN: %clang -target arm-none-none-eabi -mcpu=generic -march=armv8m.main+nodsp -### -c %s 2>&1 | FileCheck -check-prefix=CHECK-NODSP %s
+// CHECK-NODSP: "-cc1"{{.*}} "-triple" "thumbv8m.main-{{.*}} "-target-cpu" "generic"{{.*}} "-target-feature" "-dsp"
diff --git a/test/Preprocessor/arm-target-features.c b/test/Preprocessor/arm-target-features.c
index 21fedff9bf2b02424fcdd76ad99c213c335a7ef6..54eb96f06a756e4c994b28b4f41101d727c06da6 100644
--- a/test/Preprocessor/arm-target-features.c
+++ b/test/Preprocessor/arm-target-features.c
@@ -95,6 +95,42 @@
 // THUMBV8A-EABI:#define __ARM_ARCH_EXT_IDIV__ 1
 // THUMBV8A-EABI: #define __ARM_FP 0xE
 
+// RUN: %clang -target armv8m.base-none-linux-gnu -x c -E -dM %s -o - | FileCheck --check-prefix=V8M_BASELINE %s
+// V8M_BASELINE: __ARM_ARCH 8
+// V8M_BASELINE: __ARM_ARCH_8M_BASE__ 1
+// V8M_BASELINE: __ARM_ARCH_EXT_IDIV__ 1
+// V8M_BASELINE-NOT: __ARM_ARCH_ISA_ARM
+// V8M_BASELINE: __ARM_ARCH_ISA_THUMB 1
+// V8M_BASELINE: __ARM_ARCH_PROFILE 'M'
+// V8M_BASELINE-NOT: __ARM_FEATURE_CRC32
+// V8M_BASELINE-NOT: __ARM_FEATURE_DSP
+// V8M_BASELINE-NOT: __ARM_FP 0x{{.*}}
+// V8M_BASELINE-NOT: __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1
+
+// RUN: %clang -target armv8m.main-none-linux-gnu -x c -E -dM %s -o - | FileCheck --check-prefix=V8M_MAINLINE %s
+// V8M_MAINLINE: __ARM_ARCH 8
+// V8M_MAINLINE: __ARM_ARCH_8M_MAIN__ 1
+// V8M_MAINLINE: __ARM_ARCH_EXT_IDIV__ 1
+// V8M_MAINLINE-NOT: __ARM_ARCH_ISA_ARM
+// V8M_MAINLINE: __ARM_ARCH_ISA_THUMB 2
+// V8M_MAINLINE: __ARM_ARCH_PROFILE 'M'
+// V8M_MAINLINE-NOT: __ARM_FEATURE_CRC32
+// V8M_MAINLINE-NOT: __ARM_FEATURE_DSP
+// V8M_MAINLINE: __ARM_FP 0xE
+// V8M_MAINLINE: __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+
+// RUN: %clang -target arm-none-linux-gnu -march=armv8-m.main+dsp -x c -E -dM %s -o - | FileCheck --check-prefix=V8M_MAINLINE_DSP %s
+// V8M_MAINLINE_DSP: __ARM_ARCH 8
+// V8M_MAINLINE_DSP: __ARM_ARCH_8M_MAIN__ 1
+// V8M_MAINLINE_DSP: __ARM_ARCH_EXT_IDIV__ 1
+// V8M_MAINLINE_DSP-NOT: __ARM_ARCH_ISA_ARM
+// V8M_MAINLINE_DSP: __ARM_ARCH_ISA_THUMB 2
+// V8M_MAINLINE_DSP: __ARM_ARCH_PROFILE 'M'
+// V8M_MAINLINE_DSP-NOT: __ARM_FEATURE_CRC32
+// V8M_MAINLINE_DSP: __ARM_FEATURE_DSP 1
+// V8M_MAINLINE_DSP: __ARM_FP 0xE
+// V8M_MAINLINE_DSP: __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+
 // RUN: %clang -target arm-none-linux-gnu -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-DEFS %s
 // CHECK-DEFS:#define __ARM_PCS 1
 // CHECK-DEFS:#define __ARM_SIZEOF_MINIMAL_ENUM 4