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
@@ -209,6 +209,22 @@
     success = getAArch64MicroArchFeaturesFromMcpu(
         D, getAArch64TargetCPU(Args, Triple, A), Args, Features);
 
+  if (!success)
+    D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
+
+  // This matches GNU AArch64 assembler's behavior, which handles -Wa,-march
+  // after -march. And while only using the the value of last -march, it
+  // includes all the options passed via -Wa,-march.
+  success = true;
+  if ((A = Args.getLastArg(options::OPT_Wa_COMMA, options::OPT_Xassembler))) {
+    for (const Arg *A :
+         Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler))
+      for (StringRef Value : A->getValues())
+        if (Value.startswith("-march="))
+          success = getAArch64ArchFeaturesFromMarch(D, Value.substr(7), Args,
+                                                    Features);
+  }
+
   if (!success)
     D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
 
diff --git a/clang/test/Driver/aarch64-target-as-march.s b/clang/test/Driver/aarch64-target-as-march.s
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/aarch64-target-as-march.s
@@ -0,0 +1,8 @@
+/// These tests make sure that options passed to the assembler
+/// via -Wa or -Xassembler are applied correctly to assembler inputs.
+
+/// The last -march wins, and is handled before -Wa,march. All the values of -Wa,march options are added.
+// RUN: %clang --target=aarch64-linux-gnueabi -### -c -Wa,-march=armv8.1-a -march=armv8.2-a -Wa,-march=armv8.3-a -Wa,-march=armv8.4-a %s 2>&1 | \
+// RUN: FileCheck --check-prefix=TRIPLE-AARCH64 %s
+
+// TRIPLE-AARCH64: "-target-feature" "+v8.2a" "-target-feature" "+v8.1a" "-target-feature" "+v8.3a" "-target-feature" "+v8.4a"