[Bug target/60039] sh3 optimisation bug with -O2

["skrll at netbsd dot org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60039

--- Comment #3 from Nick Hudson <skrll at netbsd dot org> ---
 1b6:   93 60           mov     r9,r0
 1b8:   76 02           mov.l   r7,@(r0,r2)
        while (--nblks > 0) {
 1ba:   10 41           dt      r1
 1bc:   03 8f           bf.s    1c6 <imalloc+0xd6>
 1be:   73 62           mov     r7,r2
         * If nothing in hash bucket right now,
         * request more memory from the system.
         */
        if ((op = nextf[bucket]) == NULL) {
                morecore(bucket);
                if ((op = nextf[bucket]) == NULL)
 1c0:   08 a0           bra     1d4 <imalloc+0xe4>
 1c2:   28 22           tst     r2,r2
         * free list for this hash bucket.
         */
        nextf[bucket] = op;
        while (--nblks > 0) {
                op->ov_next = (union overhead *)((caddr_t)op + sz);
                op = (union overhead *)((caddr_t)op + sz);
 1c4:   33 62           mov     r3,r2
         * Add new memory allocated to that on
         * free list for this hash bucket.
         */
        nextf[bucket] = op;
        while (--nblks > 0) {
                op->ov_next = (union overhead *)((caddr_t)op + sz);
 1c6:   23 63           mov     r2,r3
 1c8:   dc 33           add     r13,r3
        /*
         * Add new memory allocated to that on
         * free list for this hash bucket.
         */
        nextf[bucket] = op;
        while (--nblks > 0) {
 1ca:   10 41           dt      r1
 1cc:   fa 8f           bf.s    1c4 <imalloc+0xd4>
 1ce:   32 22           mov.l   r3,@r2
 1d0:   73 62           mov     r7,r2

r2 at 0x1ce is somehow wrong