Enzyme mutates enzyme_const array when optimization flag -O1 or further used

[akdemironur]

[LLVM 16, Enzyme v0.0.98]
Here is the sample code:

void __enzyme_autodiff(void *, ...);
int enzyme_const, enzyme_dup, enzyme_out, enzyme_dupnoneed;

#include <stdio.h>

void foo(const double *p, double *r, int *type, double *val)
{
    for (size_t i = 0; i < 5; ++i)
    {
        double O, N;
        O = p[i];
        if (type[i] == 0)
        {
            N = val[i];
        }
        else
        {
            N = p[(i + 1) % 5];
        }
        r[i] = O + N;
    }
}

int main()
{
    int type[5] = {0};
    double val[5] = {0}, r[5] = {0}, grad_p[5] = {0}, grad_r[5] = {0, 0, 1, 0, 0};
    const double p[5] = {1};

    printf("val[init]:\t%6.3f %6.3f %6.3f %6.3f %6.3f\n", val[0], val[1], val[2], val[3], val[4]);

    foo(p, r, type, val);

    printf("val[foo]:\t%6.3f %6.3f %6.3f %6.3f %6.3f\n", val[0], val[1], val[2], val[3], val[4]);

    __enzyme_autodiff(foo, enzyme_dup, p, grad_p, enzyme_dupnoneed, r, grad_r, enzyme_const, type, enzyme_const, val);

    printf("val[enzyme]:\t%6.3f %6.3f %6.3f %6.3f %6.3f\n", val[0], val[1], val[2], val[3], val[4]);
}

When I compile this code with -O0 opt I get this output as expected:

val[init]:	 0.000  0.000  0.000  0.000  0.000
val[foo]:	 0.000  0.000  0.000  0.000  0.000
val[enzyme]:	 0.000  0.000  0.000  0.000  0.000

When I compile it with -O1/2/3

val[init]:	 0.000  0.000  0.000  0.000  0.000
val[foo]:	 0.000  0.000  0.000  0.000  0.000
val[enzyme]:	 0.000  0.000  1.000  0.000  0.000

The workaround I am using for this issue is, changing N = p[(i + 1) % 5]; to N = p[(i + 1) % 5] + 0; With this change compilation with optimization flags are working as well.