avf: 512-bit SIMD version of avf_tx_prepare

Exploiting AVX-512 operations on avf_tx_prepare().

Type: improvement

Signed-off-by: Leyi Rong <leyi.rong@intel.com>
Change-Id: I01e0b4a2e2d440659b4298668a868d983f5091c3
diff --git a/src/vppinfra/vector_avx512.h b/src/vppinfra/vector_avx512.h
index 96c78e4..eda65ca 100644
--- a/src/vppinfra/vector_avx512.h
+++ b/src/vppinfra/vector_avx512.h
@@ -99,6 +99,9 @@
   return (u32) _mm512_movepi16_mask ((__m512i) v);
 }
 
+#define u64x8_i64gather(index, base, scale)                                   \
+  (u64x8) _mm512_i64gather_epi64 ((__m512i) index, base, scale)
+
 /* 512-bit packs */
 #define _(f, t, fn)                                                           \
   always_inline t t##_pack (f lo, f hi)                                       \