vppinfra: add 128-bit and 512-bit a ^ b ^ c shortcut

This allows us to combine 2 XOR operations into signle instruction
which makes difference in crypto op:

- in x86, by using ternary logic instruction
- on ARM, by using EOR3 instruction (available with sha3 feature)

Type: refactor
Change-Id: Ibdf9001840399d2f838d491ca81b57cbd8430433
Signed-off-by: Damjan Marion <damjan.marion@gmail.com>
diff --git a/src/vppinfra/vector_sse42.h b/src/vppinfra/vector_sse42.h
index c22e86e..e75580e 100644
--- a/src/vppinfra/vector_sse42.h
+++ b/src/vppinfra/vector_sse42.h
@@ -746,6 +746,15 @@
   return (u8x16) _mm_blendv_epi8 ((__m128i) v1, (__m128i) v2, (__m128i) mask);
 }
 
+static_always_inline u8x16
+u8x16_xor3 (u8x16 a, u8x16 b, u8x16 c)
+{
+#if __AVX512F__
+  return (u8x16) _mm_ternarylogic_epi32 ((__m128i) a, (__m128i) b,
+					 (__m128i) c, 0x96);
+#endif
+  return a ^ b ^ c;
+}
 
 #endif /* included_vector_sse2_h */