GCC 13+ build failure: blake2.h alignment error

[melvincarvalho]

Problem

Building with GCC 13+ fails with alignment errors in blake2.h:

blake2.h:101:5: error: size of array element is not a multiple of its alignment
  101 |     blake2s_state S[8][1];
      |     ^~~~~~~~~~~~~
blake2.h:102:5: error: size of array element is not a multiple of its alignment
  102 |     blake2s_state R[1];

Cause

GCC 13 is stricter about alignment constraints. The blake2s_state and blake2b_state structs are declared with ALIGN(64) but their sizes are not multiples of 64 bytes. When these aligned structs are used in arrays inside #pragma pack(push, 1), GCC 13 rejects this as invalid.

Solution

Two changes needed:

1. Remove ALIGN(64) from blake2s_state and blake2b_state struct definitions (not needed for reference implementation)
2. Move #pragma pack(pop) before the parallel state structures (blake2sp_state, blake2bp_state) which contain arrays of the aligned types

Environment

• GCC 13.3.0 (Ubuntu 24.04)
• Affects clean builds from source

Related

• Issue GCC 13 optimization bug causes LYRA2REv2 hash failures - fix identified #141 - GCC 13 BMW256 optimization bug (separate issue, same compiler)