diff --git a/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
index 1f0f9eb4687..8baa3a6ce6a 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
@@ -680,8 +680,11 @@ MCAsmBackend *llvm::createARMAsmBackend(const Target &T, StringRef TT, StringRef
     return new DarwinARMAsmBackend(T, TT, CS);
   }
 
+#if 0
+  // FIXME: Introduce yet another checker but assert(0).
   if (TheTriple.isOSBinFormatCOFF())
-    llvm_unreachable("Windows not supported on ARM");
+    assert(0 && "Windows not supported on ARM");
+#endif
 
   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS());
   return new ELFARMAsmBackend(T, TT, OSABI);
diff --git a/test/MC/ARM/arm-thumb-cpus-default.s b/test/MC/ARM/arm-thumb-cpus-default.s
index 040039f2154..636ee3c5057 100644
--- a/test/MC/ARM/arm-thumb-cpus-default.s
+++ b/test/MC/ARM/arm-thumb-cpus-default.s
@@ -5,9 +5,6 @@
 @ RUN: llvm-mc -show-encoding -triple=armv7m < %s | FileCheck %s --check-prefix=CHECK-THUMB-ONLY
 @ RUN: llvm-mc -show-encoding -triple=armv6m < %s | FileCheck %s --check-prefix=CHECK-THUMB-ONLY
 
-@ FIXME: Could we avoid XFAIL to specify triple above?
-@ XFAIL: cygwin,mingw32,win32
-
         @ Make sure the architecture chosen by LLVM defaults to a compatible
         @ ARM/Thumb mode.
         movs r0, r0
diff --git a/test/MC/ARM/arm-thumb-cpus.s b/test/MC/ARM/arm-thumb-cpus.s
index ea4e71a6aca..c15e8078186 100644
--- a/test/MC/ARM/arm-thumb-cpus.s
+++ b/test/MC/ARM/arm-thumb-cpus.s
@@ -5,9 +5,6 @@
 @ RUN: llvm-mc -show-encoding -triple=armv7m < %s 2>&1 | FileCheck %s --check-prefix=CHECK-THUMB-ONLY
 @ RUN: llvm-mc -show-encoding -triple=armv6m < %s 2>&1 | FileCheck %s --check-prefix=CHECK-THUMB-ONLY
 
-@ FIXME: Could we avoid XFAIL to specify triple above?
-@ XFAIL: cygwin,mingw32,win32
-
         @ Make sure correct diagnostics are given for CPUs without support for
         @ one or other of the execution states.
         .thumb