Add Two Arrays

Given two arrays of 32-bit signed integers a and b, compute their element-wise sum into output array c such that c[i] = a[i] + b[i] for all i.

Function Signature

#include <immintrin.h>
#include <cstdint>

void add_arrays(const int32_t* a, const int32_t* b, int32_t* c, int n);

Parameters:

• a — pointer to the first input array of n signed 32-bit integers, guaranteed 32-byte aligned
• b — pointer to the second input array of n signed 32-bit integers, guaranteed 32-byte aligned
• c — pointer to the output array of n signed 32-bit integers, guaranteed 32-byte aligned
• n — number of elements, guaranteed to be a multiple of 8 and at least 8

Returns: nothing — results are written to c

Example

a = [1, 2, 3, 4, 5, 6, 7, 8]
b = [10, 20, 30, 40, 50, 60, 70, 80]
c = [11, 22, 33, 44, 55, 66, 77, 88]

Constraints

• 8 ≤ n ≤ 1,000,000
• n is always a multiple of 8
• All elements are in range [-10000, 10000]
• Results fit in int32_t
• a, b, and c are all 32-byte aligned

Notes

This is the "Hello, World!" of SIMD. Your solution should use AVX2 intrinsics to process 8 integers at a time — load a chunk from each input, add them together, and store the result.

Useful Intrinsics