arm: reinstate HAVE_GAS_ARM_EXTENDED_ARCH

The check was removed by accident.

gcc/ChangeLog:

	* config.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Reinstate HAVE_GAS_ARM_EXTENDED_ARCH test.

diff --git a/gcc/config.in b/gcc/config.in
index 6a4f8856c4f..16bb963b45b 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -1331,6 +1331,13 @@
 #endif
 
 
+/* Define if your Arm assembler permits context-specific feature extensions.
+   */
+#ifndef USED_FOR_TARGET
+#undef HAVE_GAS_ARM_EXTENDED_ARCH
+#endif
+
+
 /* Define if your assembler supports .balign and .p2align. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_GAS_BALIGN_AND_P2ALIGN
diff --git a/gcc/configure b/gcc/configure
index 095065ed01a..a52574d02b5 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -731,10 +731,10 @@ gcc_cv_dsymutil
 gcc_cv_otool
 gcc_cv_readelf
 gcc_cv_objdump
-ORIGINAL_NM_FOR_TARGET
-gcc_cv_nm
 ORIGINAL_OBJCOPY_FOR_TARGET
 gcc_cv_objcopy
+ORIGINAL_NM_FOR_TARGET
+gcc_cv_nm
 ORIGINAL_LD_GOLD_FOR_TARGET
 ORIGINAL_LD_BFD_FOR_TARGET
 ORIGINAL_LD_FOR_TARGET
@@ -19676,7 +19676,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19676 "configure"
+#line 19679 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -19782,7 +19782,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19782 "configure"
+#line 19785 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -29118,6 +29118,44 @@ $as_echo "$gcc_cv_as_version, ok" >&6; }
     ;;
 esac
 
+case "$target" in
+  arm*)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for assembler for arm accepts context-specific architecture extensions" >&5
+$as_echo_n "checking assembler for assembler for arm accepts context-specific architecture extensions... " >&6; }
+if ${gcc_cv_as_arm_option_extensions+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  gcc_cv_as_arm_option_extensions=no
+  if test x$gcc_cv_as != x; then
+    $as_echo '.text
+	.thumb
+	.syntax unified
+	vmov.f32 s0, s1' > conftest.s
+    if { ac_try='$gcc_cv_as $gcc_cv_as_flags -march=armv8.1-m.main+mve -o conftest.o conftest.s >&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+    then
+	gcc_cv_as_arm_option_extensions=yes
+    else
+      echo "configure: failed program was" >&5
+      cat conftest.s >&5
+    fi
+    rm -f conftest.o conftest.s
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_arm_option_extensions" >&5
+$as_echo "$gcc_cv_as_arm_option_extensions" >&6; }
+if test $gcc_cv_as_arm_option_extensions = yes; then
+
+$as_echo "#define HAVE_GAS_ARM_EXTENDED_ARCH 1" >>confdefs.h
+
+fi
+
+esac
+
 # ??? Not all targets support dwarf2 debug_line, even within a version
 # of gas.  Moreover, we need to emit a valid instruction to trigger any
 # info to the output file.  So, as supported targets are added to gas 2.11,
diff --git a/gcc/configure.ac b/gcc/configure.ac
index e098b905622..5fe826aa4eb 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5427,6 +5427,19 @@ case "$target" in
     ;;
 esac
 
+case "$target" in
+  arm*)
+    gcc_GAS_CHECK_FEATURE([assembler for arm accepts context-specific architecture extensions],
+      gcc_cv_as_arm_option_extensions,
+      [-march=armv8.1-m.main+mve],
+      [.text
+	.thumb
+	.syntax unified
+	vmov.f32 s0, s1],,
+      [AC_DEFINE(HAVE_GAS_ARM_EXTENDED_ARCH, 1,
+       [Define if your Arm assembler permits context-specific feature extensions.])])
+esac
+
 # ??? Not all targets support dwarf2 debug_line, even within a version
 # of gas.  Moreover, we need to emit a valid instruction to trigger any
 # info to the output file.  So, as supported targets are added to gas 2.11,