feat:using neon to merge registers

Author: Max-Cheng

be/src/olap/hll.h

@@ -25,6 +25,8 @@
 
 #ifdef __x86_64__
 #include <immintrin.h>
+#elif __aarch64__
+#include <arm_neon.h>
 #endif
 
 #include "vec/common/hash_table/phmap_fwd_decl.h"
@@ -287,6 +289,17 @@ class HyperLogLog {
             src += 32;
             dst += 32;
         }
+#elif __aarch64__
+        int loop = HLL_REGISTERS_COUNT / 16;
+        uint8_t* dst = _registers;
+        const uint8_t* src = other_registers;
+        for (int i = 0; i < loop; i++) {
+            uint8x16_t va = vld1q_u8(dst);
+            uint8x16_t vb = vld1q_u8(src);
+            vst1q_u8(dst, vmaxq_u8(va, vb));
+            src += 16;
+            dst += 16;
+        }
 #else
         for (int i = 0; i < HLL_REGISTERS_COUNT; ++i) {
             _registers[i] =