Min of Array

Given an array of 32-bit signed integers, find and return the minimum value using AVX2 intrinsics.

Function Signature

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

int32_t array_min(const int32_t* arr, int n);

Parameters:

arr — pointer to an 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: the minimum element in the array

Example

Input:  [3, 1, 4, 1, 5, 9, 2, 6]
Output: 1

Constraints

8 ≤ n ≤ 1,000,000
n is always a multiple of 8
All elements are in range [-1,000,000, 1,000,000]
arr is 32-byte aligned

Notes

Your solution should use AVX2 intrinsics to compare 8 integers at a time. Unlike a sum reduction, you cannot use _mm_hadd for the final horizontal step — you need a shuffle-and-min pattern instead.

Useful Intrinsics

Intrinsic	Description
`_mm256_load_si256(ptr)`	Load 256 bits from aligned memory
`_mm256_min_epi32(a, b)`	Packed 32-bit integer minimum
`_mm256_extracti128_si256(v, 1)`	Extract high 128-bit lane
`_mm256_castsi256_si128(v)`	Cast to low 128-bit lane (free)
`_mm_min_epi32(a, b)`	Packed 32-bit integer minimum (128-bit)
`_mm_shuffle_epi32(v, imm)`	Shuffle 32-bit elements within 128-bit register
`_mm_extract_epi32(v, idx)`	Extract a 32-bit integer