add 'is_all_zero(x)' for NEON
#define u16x8_sub_saturate(a,b) vsubq_u16(a,b)
#define i16x8_sub_saturate(a,b) vsubq_s16(a,b)
+always_inline int
+u8x16_is_all_zero (u8x16 x)
+{
+ return !(vaddvq_u8 (x));
+}
+
+always_inline int
+u16x8_is_all_zero (u16x8 x)
+{
+ return !(vaddvq_u16 (x));
+}
+
+always_inline int
+u32x4_is_all_zero (u32x4 x)
+{
+ return !(vaddvq_u32 (x));
+}
+
+always_inline int
+u64x2_is_all_zero (u64x2 x)
+{
+ return !(vaddvq_u64 (x));
+}
+
/* Converts all ones/zeros compare mask to bitmap. */
always_inline u32
u8x16_compare_byte_mask (u8x16 x)
