Aligning memory on 16-byte and 32-byte boundaries

Question

I'm doing several operations using SIMD instructions (SSE and AVX). As I understand, SSE instructions work best with 16-byte aligned memory, and AVX instructions work best with 32-byte aligned memory.

Would it be safe to always allocate memory aligned to 32-byte boundaries for optimal use with both SSE and AVX?

Are there ever any cases where 32-byte aligned memory is not also 16-byte aligned?

Answer 1

Are there ever any cases where 32-byte aligned memory is not also 16-byte aligned?

Alignment just means that the address is a multiple of 32. Any multiple of 32 is also a multiple of 16.

The first google hit for "alignment" is wikipedia, and you can follow the links to https://en.wikipedia.org/wiki/Data_structure_alignment#Definitions, which explains this in lots of detail.