crash.c

// Build x64 version with "cl -O2 /fp:fast crash.c"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

struct TonalityAnalysis {
    int count[2]; //< Remove this or change it to multiples of 4 and it works
    float std[4];
};

int main() {
    int i;
    struct TonalityAnalysis *tonal = (struct TonalityAnalysis*)calloc(1, sizeof(struct TonalityAnalysis));
    float features[4];

    for (i = 0; i<4; i++)
        features[i] = (float) sqrt(tonal->std[i]); //< Crash here

    for (i = 0; i<4; i++)
        printf("%.2f\n", features[i]);

    return 0;
}