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/* { dg-do run } */

/* { dg-options "-std=gnu99 -Wall -Wextra -O1" } */

extern void *memset (void*, int, __SIZE_TYPE__);

extern void abort (void);

struct radix_tree_root {

        unsigned int height;

        struct radix_tree_node *rnode;

};

struct radix_tree_node {

        unsigned int count;

        void *slots[64];

        unsigned long tags[2][2];

};

struct radix_tree_path {

        struct radix_tree_node *node, **slot;

        int offset;

};

static unsigned long height_to_maxindex[7] =

{0, 63, 4095, 262143, 16777215, 1073741823, 4294967295};

static inline void tag_clear(struct radix_tree_node *node, int tag, int offset)

{

        int nr;

        volatile unsigned long *addr;

        int mask;

        nr = offset;

        addr = &node->tags[tag][0];

        addr += nr >> 5;

        mask = 1 << (nr & 0x1f);

        *addr &= ~mask;

}

void *radix_tree_tag_clear(struct radix_tree_root *root, unsigned long index, int tag)

{

        struct radix_tree_path path[7], *pathp = path;

        unsigned int height, shift;

        void *ret = 0;

        height = root->height;

        if (index > height_to_maxindex[height])

                goto out;

        shift = (height - 1) * 6;

        pathp->node = 0;

        pathp->slot = &root->rnode;

        while (height > 0) {

                int offset;

                if (*pathp->slot == 0)

                        goto out;

                offset = (index >> shift) & (64-1);

                pathp[1].offset = offset;

                pathp[1].node = *pathp[0].slot;

                pathp[1].slot = (struct radix_tree_node **)

                        (pathp[1].node->slots + offset);

                pathp++;

                shift -= 6;

                height--;

        }

        ret = *pathp[0].slot;

        if (ret == 0)

                goto out;

        do {

                int idx;

                tag_clear(pathp[0].node, tag, pathp[0].offset);

                for (idx = 0; idx < 2; idx++) {

                        if (pathp[0].node->tags[tag][idx])

                                goto out;

                }

                pathp--;

        } while (pathp[0].node);

out:

        return ret;

}

int main ()

{

        struct radix_tree_root r;

        struct radix_tree_node node;

        void *p = (void *) 0xdeadbeef;

        r.height = 1;

        r.rnode = &node;

        memset (&node, 0, sizeof (node));

        node.count = 1;

        node.slots [13] = p;

        radix_tree_tag_clear (&r, 13, 1);

        if (r.rnode->slots[13] != p)

                abort ();

        return 0;

}