diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index 3be71ce9b61ecf7a36015e467cb50f8ceb3e7973..e806cb9f1c94de9e6fb1541cce6551135843da0e 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -15,6 +15,7 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCELF.h"
@@ -96,6 +97,9 @@ void MCELFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
 }
 
 void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
+  // Let the target do whatever target specific stuff it needs to do.
+  getAssembler().getBackend().handleAssemblerFlag(Flag);
+  // Do any generic stuff we need to do.
   switch (Flag) {
   case MCAF_SyntaxUnified: return; // no-op here.
   case MCAF_Code16: return; // Change parsing mode; no-op here.
diff --git a/llvm/test/MC/ARM/align_arm_2_thumb.s b/llvm/test/MC/ARM/align_arm_2_thumb.s
new file mode 100644
index 0000000000000000000000000000000000000000..120e96480b5cb8956f64691753f29012224bb641
--- /dev/null
+++ b/llvm/test/MC/ARM/align_arm_2_thumb.s
@@ -0,0 +1,15 @@
+@ RUN: llvm-mc -triple armv7-none-linux -filetype=obj -o %t.o %s
+@ RUN: llvm-objdump -triple thumbv7-none-linux -d %t.o | FileCheck --check-prefix=ARM_2_THUMB %s
+
+@ RUN: llvm-mc -triple armv7-apple-darwin -filetype=obj -o %t_darwin.o %s
+@ RUN: llvm-objdump -triple thumbv7-apple-darwin -d %t_darwin.o | FileCheck --check-prefix=ARM_2_THUMB %s
+
+.syntax unified
+.code 16
+@ ARM_2_THUMB-LABEL: foo
+foo:
+  add r0, r0
+.align 3
+@ ARM_2_THUMB: 2: 00 bf     nop
+  add r0, r0
+
diff --git a/llvm/test/MC/ARM/align_thumb_2_arm.s b/llvm/test/MC/ARM/align_thumb_2_arm.s
new file mode 100644
index 0000000000000000000000000000000000000000..328bfabce65c35392dd3f8fd44b2f1a5288ef6a5
--- /dev/null
+++ b/llvm/test/MC/ARM/align_thumb_2_arm.s
@@ -0,0 +1,15 @@
+@ RUN: llvm-mc -triple thumbv7-none-linux -filetype=obj -o %t.o %s
+@ RUN: llvm-objdump -triple armv7-none-linux -d %t.o | FileCheck --check-prefix=THUMB_2_ARM %s
+
+@ RUN: llvm-mc -triple thumbv7-apple-darwin -filetype=obj -o %t_darwin.o %s
+@ RUN: llvm-objdump -triple armv7-apple-darwin -d %t_darwin.o | FileCheck --check-prefix=THUMB_2_ARM %s
+
+.syntax unified
+.code 32
+@ THUMB_2_ARM-LABEL: foo
+foo:
+  add r0, r0
+.align 3
+@ THUMB_2_ARM: 4: 00 f0 20 e3    nop
+  add r0, r0
+