Build failure with gcc 15.2, ` error: ‘acc’ may be used uninitialized`

[krampenschiesser]

Trying to build this library sadly fails:

/home/scar/projects/ZenDNN/zendnnl/src/lowoha_operators/matmul/matmul_native/brgemm/kernel/fp32/fp32_brgemm_ukernel.cpp: In function ‘void zendnnl::lowoha::matmul::native::brgemm_tail_kernel(const float*, int, const float*, int, float*, int, int, int, int, int, float, const float*, fused_postop_t)’:
/home/scar/projects/ZenDNN/zendnnl/src/lowoha_operators/matmul/matmul_native/brgemm/kernel/fp32/fp32_brgemm_ukernel.cpp:185:50: error: ‘acc’ may be used uninitialized [-Werror=maybe-uninitialized]
  185 |                 acc[m][full_vecs] = _mm512_add_ps(acc[m][full_vecs], bv);
      |                                     ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/home/scar/projects/ZenDNN/zendnnl/src/lowoha_operators/matmul/matmul_native/brgemm/kernel/fp32/fp32_brgemm_ukernel.cpp:133:12: note: ‘acc’ declared here
  133 |     __m512 acc[MAX_MR][MAX_NV];
      |            ^~~
cc1plus: all warnings being treated as errors
gmake[6]: *** [src/CMakeFiles/zendnnl_archive.dir/build.make:1034: src/CMakeFiles/zendnnl_archive.dir/lowoha_operators/matmul/matmul_native/brgemm/kernel/fp32/fp32_brgemm_ukernel.cpp.o] Error 1
gmake[6]: *** Waiting for unfinished jobs....
/home/scar/projects/ZenDNN/zendnnl/src/lowoha_operators/matmul/matmul_native/gemm/kernel/fp32/fp32_gemm_ukernel.cpp: In function ‘void zendnnl::lowoha::matmul::native::avx512_tail_kernel(const float*, int, const float*, int, float*, int, int, int, int, float, const float*, fused_postop_t)’:
/home/scar/projects/ZenDNN/zendnnl/src/lowoha_operators/matmul/matmul_native/gemm/kernel/fp32/fp32_gemm_ukernel.cpp:387:50: error: ‘acc’ may be used uninitialized [-Werror=maybe-uninitialized]
  387 |                 acc[m][full_vecs] = _mm512_add_ps(acc[m][full_vecs], bv);
      |                                     ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/home/scar/projects/ZenDNN/zendnnl/src/lowoha_operators/matmul/matmul_native/gemm/kernel/fp32/fp32_gemm_ukernel.cpp:338:12: note: ‘acc’ declared here
  338 |     __m512 acc[12][4];
      |            ^~~
cc1plus: all warnings being treated as errors

tried both the current main branch and the release v5.2.1

build commands:

cmake -DZENDNNL_BUILD_TYPE=Release  -DZENDNNL_BUILD_EXAMPLES=OFF ..
cmake --build . --target zendnnl -j$(nproc)