diff --git a/gcc/config/i386/gnu-user64.h b/gcc/config/i386/gnu-user64.h
index 911fbd4651c..c7f65148ec7 100644
--- a/gcc/config/i386/gnu-user64.h
+++ b/gcc/config/i386/gnu-user64.h
@@ -50,7 +50,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define ASM_SPEC "%{" SPEC_32 ":--32} \
  %{" SPEC_64 ":--64} \
  %{" SPEC_X32 ":--x32} \
- %{msse2avx:%{!mavx:-msse2avx}}"
+ %{msse2avx:%{!mavx:-msse2avx}} \
+ %{mmpx:-march=+mpx}"
 
 #define GNU_USER_TARGET_LINK_SPEC				   \
                   "%{" SPEC_64 ":-m " GNU_USER_LINK_EMULATION64 "} \
diff --git a/libmpx/configure b/libmpx/configure
index 2fd71ca89f6..90ed6ec2149 100644
--- a/libmpx/configure
+++ b/libmpx/configure
@@ -5135,7 +5135,7 @@ fi
 
 # Check we may build wrappers library
 echo "test:  bndmov %bnd0, %bnd1" > conftest.s
-if { ac_try='$AS -o conftest.o conftest.s 1>&5'
+if { ac_try='$AS -march=+mpx -o conftest.o conftest.s 1>&5'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
diff --git a/libmpx/configure.ac b/libmpx/configure.ac
index baa882b16b0..32c5c8f4aa0 100644
--- a/libmpx/configure.ac
+++ b/libmpx/configure.ac
@@ -100,7 +100,7 @@ AC_CHECK_TOOL(RANLIB, ranlib, :)
 
 # Check we may build wrappers library
 echo "test:  bndmov %bnd0, %bnd1" > conftest.s
-if AC_TRY_COMMAND([$AS -o conftest.o conftest.s 1>&AS_MESSAGE_LOG_FD])
+if AC_TRY_COMMAND([$AS -march=+mpx -o conftest.o conftest.s 1>&AS_MESSAGE_LOG_FD])
 then
     mpx_as=yes
 else