diff --git a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
--- a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -82,6 +82,25 @@
     else
       return false;
 
+    // +sme implies +bf16.
+    // +sme-f64f64 and +sme-i16i64 both imply +sme.
+    if (Feature == "sme") {
+      Features.push_back("+bf16");
+    } else if (Feature == "nosme") {
+      Features.push_back("-sme-f64f64");
+      Features.push_back("-sme-i16i64");
+    } else if (Feature == "sme-f64f64") {
+      Features.push_back("+sme");
+      Features.push_back("+bf16");
+    } else if (Feature == "sme-i16i64") {
+      Features.push_back("+sme");
+      Features.push_back("+bf16");
+    } else if (Feature == "nobf16") {
+      Features.push_back("-sme");
+      Features.push_back("-sme-f64f64");
+      Features.push_back("-sme-i16i64");
+    }
+
     if (Feature == "sve2")
       Features.push_back("+sve");
     else if (Feature == "sve2-bitperm" || Feature == "sve2-sha3" ||
diff --git a/clang/test/Driver/aarch64-implied-sme-features.c b/clang/test/Driver/aarch64-implied-sme-features.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/aarch64-implied-sme-features.c
@@ -0,0 +1,49 @@
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme %s -### 2>&1 | FileCheck %s --check-prefix=SME-IMPLY
+// SME-IMPLY: "-target-feature" "+sme" "-target-feature" "+bf16"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+nosme %s -### 2>&1 | FileCheck %s --check-prefix=NOSME
+// NOSME: "-target-feature" "-sme"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme+nosme %s -### 2>&1 | FileCheck %s --check-prefix=SME-REVERT
+// SME-REVERT-NOT: "-target-feature" "+sme"
+// SME-REVERT: "-target-feature" "+bf16" "-target-feature" "-sme" "-target-feature" "-sme-f64f64" "-target-feature" "-sme-i16i64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme+nobf16 %s -### 2>&1 | FileCheck %s --check-prefix=SME-CONFLICT
+// SME-CONFLICT-NOT: "-target-feature" "+sme"
+// SME-CONFLICT-NOT: "-target-feature" "+bf16"
+// SME-CONFLICT: "-target-feature" "-bf16" "-target-feature" "-sme" "-target-feature" "-sme-f64f64" "-target-feature" "-sme-i16i64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme-i16i64 %s -### 2>&1 | FileCheck %s --check-prefix=SME-I16I64
+// SME-I16I64: "-target-feature" "+sme-i16i64" "-target-feature" "+sme" "-target-feature" "+bf16"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+nosme-i16i64 %s -### 2>&1 | FileCheck %s --check-prefix=NOSME-I16I64
+// NOSME-I16I64-NOT: "-target-feature" "+sme-i16i64"
+// NOSME-I16I64-NOT: "-target-feature" "+sme"
+// NOSME-I16I64-NOT: "-target-feature" "+bf16"
+// NOSME-I16I64:     "-target-feature" "-sme-i16i64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme-i16i64+nosme-i16i64 %s -### 2>&1 | FileCheck %s --check-prefix=SME-I16I64-REVERT
+// SME-I16I64-REVERT: "-target-feature" "+sme" "-target-feature" "+bf16" "-target-feature" "-sme-i16i64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+nosme-f64f64 %s -### 2>&1 | FileCheck %s --check-prefix=NOSME-F64F64
+// NOSME-F64F64-NOT: "-target-feature" "+sme-f64f64"
+// NOSME-F64F64-NOT: "-target-feature" "+sme"
+// NOSME-F64F64-NOT: "-target-feature" "+bf16"
+// NOSME-F64F64:     "-target-feature" "-sme-f64f64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme-f64f64+nosme-f64f64 %s -### 2>&1 | FileCheck %s --check-prefix=SME-F64F64-REVERT
+// SME-F64F64-REVERT: "-target-feature" "+sme" "-target-feature" "+bf16" "-target-feature" "-sme-f64f64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme-f64f64+nosme-i16i64 %s -### 2>&1 | FileCheck %s --check-prefix=SME-SUBFEATURE-MIX
+// SME-SUBFEATURE-MIX: "-target-feature" "+sme-f64f64" "-target-feature" "+sme" "-target-feature" "+bf16" "-target-feature" "-sme-i16i64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme-i16i64+nosme %s -### 2>&1 | FileCheck %s --check-prefix=SME-SUBFEATURE-CONFLICT1
+// SME-SUBFEATURE-CONFLICT1: "-target-feature" "+bf16" "-target-feature" "-sme" "-target-feature" "-sme-f64f64" "-target-feature" "-sme-i16i64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+sme-f64f64+nobf16 %s -### 2>&1 | FileCheck %s --check-prefix=SME-SUBFEATURE-CONFLICT2
+// SME-SUBFEATURE-CONFLICT2-NOT: "-target-feature" "+bf16"
+// SME-SUBFEATURE-CONFLICT2-NOT: "-target-feature" "+sme"
+// SME-SUBFEATURE-CONFLICT2-NOT: "-target-feature" "+sme-f64f64"
+
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a+nosme+sme-i16i64 %s -### 2>&1 | FileCheck %s --check-prefix=SME-SUBFEATURE-CONFLICT-REV
+// SME-SUBFEATURE-CONFLICT-REV: "-target-feature" "-sme-f64f64" "-target-feature" "+sme-i16i64" "-target-feature" "+sme" "-target-feature" "+bf16"