ARM: check ARMv6 support at the same time as NEON

Our NEON optimizations don't compile on ARMv5 and lower. It is
dubious that there would be any use for NEON on such processor anyway.

diff --git a/configure.ac b/configure.ac
index b6b7f910577da21bbfebb6542cd5bbd741a54bb9..1585ade39dd6e94023cb6d031113df0e0089ee9b 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -1351,7 +1351,10 @@ AS_IF([test "${enable_neon}" != "no"], [
   AC_CACHE_CHECK([if $CC groks NEON inline assembly], [ac_cv_neon_inline], [
     CFLAGS="${CFLAGS_save} -mfpu=neon"
     AC_COMPILE_IFELSE([
-      AC_LANG_PROGRAM(,[[asm volatile("vqmovun.s64 d0, q1":::"d0");]])
+      AC_LANG_PROGRAM(,[[
+asm volatile("vqmovun.s64 d0, q1":::"d0");
+asm volatile("qadd r0, r0, r0":::"r0"); /* assume ARMv6 */
+]])
     ], [
       ac_cv_neon_inline="-mfpu=neon"
     ], [