gcc/clang usage of restrict keyword for local variables and struct fields

Can't figure out how to convince gcc/clang that my pointers don't intersect; for what I see, it looks like restrict is only honored if specified in function arguments and ignored otherwise. Here is my code:

#if defined(_MSC_VER) || defined(__cplusplus)
#define restrict __restrict
#endif

struct s {
    int sz;
    int *a;
    int *b;
};

struct s_r {
    int sz;
    int *restrict a;
    int *restrict b;
};

void foo_dumb_struct(struct s *s, int c) {
    int sz = s->sz;
    for(int i = 0; i != sz; ++i) {
        s->a[i] = s->b[0] + c;
    }
}

void foo_restricted_arrays(int sz,
        int *restrict a, int *restrict b,
        int c) {
    for(int i = 0; i != sz; ++i) {
        a[i] = b[0] + c;
    }
}

void foo_restricted_struct(struct s_r *s, int c) {
    int sz = s->sz;
    for(int i = 0; i != sz; ++i) {
        s->a[i] = s->b[0] + c;
    }
}

void foo_restricted_subcall(struct s *s, int c) {
    foo_restricted_arrays(s->sz, s->a, s->b, c);
}

void foo_restricted_cast(struct s *s, int c) {
    int sz = s->sz;
    int *restrict a = s->a;
    int *restrict b = s->b;
    for(int i = 0; i != sz; ++i) {
        a[i] = b[0] + c;
    }
}

Icc is fine with this code, but gcc/clang generates re-read of b[0] on each iteration for foo_restricted_struct and foo_restricted_cast, for all architectures I could test with godbolt. Any time it is used in function arguments (including nested functions or C++ lambdas) it is fine and extra load is removed. https://cellperformance.beyond3d.com/articles/2006/05/demystifying-the-restrict-keyword.html suggests that it actually worked as I want it to, but I'm not sure their gcc wasn't customized for cell specifically.

Is my usage of restrict wrong, or gcc/clang only implements restrict for function arguments and nothing else?