potential unitialized variable in nnp_sgemm_upto_4x8__psimd

[yonghong-song]

In src/psimd/blas/sgemm.c, we have

void nnp_sgemm_upto_4x8__psimd(uint32_t mr, uint32_t nr, size_t k, size_t update, const float* a, const float* b, float* c, size_t row_stride_c) {
    psimd_f32 vc00, vc01, vc10, vc11, vc20, vc21, vc30, vc31;
    vc00 = vc01 = vc10 = vc11 = vc20 = vc21 = vc30 = vc31 = psimd_zero_f32();
    do {
        psimd_f32 vb0, vb1;

        vb0 = psimd_load_f32(b);
        b += 4;
        if (nr > 4) {
            vb1 = psimd_load_f32(b);
            b += 4;
        }
...

Here, vb1 could be potentially uninitialized if nr <= 4. Is this something we should worry about? In one of our compilations, compiler complains

variable 'vb1' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
                if (nr > 4) {
                    ^~~~~~

[Maratyszcza]

The variable is indeed uninitialized when nr <= 4, but it doesn't affect the correctness because its final value is discarded in this case.