Missed pointer return value optimization

[ZERICO2005]

https://godbolt.org/z/bxT3aPjbd

The gmtime function always returns _gmtime.tm2 in HL. However, it seems that when localetime and gmtime are in the same translation unit, it decides to reload the value of _gmtime.tm2 into HL, even though HL will already always be set to that value.

struct tm *gmtime(const time_t *tp);
struct tm *localtime(const time_t *timer) {
    time_t timer2 = *timer;
    // subtracts zero since LOCALTIME_GMT_OFFSET is zero
    timer2 -= LOCALTIME_GMT_OFFSET * SECS_PER_MIN;
    return gmtime(&timer2);
}

Same translation unit as gmtime:

BB0_27:
        ld      (_gmtime.tm2), bc
        ld      hl, _gmtime.tm2
        ld      sp, ix
        pop     ix
        ret

        public  _localtime
_localtime:
        ld      hl, -4
        call    __frameset
        ld      iy, (ix + 6)
        ld      hl, (iy)
        ld      a, (iy + 3)
        ld      (ix - 4), hl
        ld      (ix - 1), a
        pea     ix - 4
        call    _gmtime
        pop     hl
        ld      hl, _gmtime.tm2
        ld      sp, ix
        pop     ix
        ret

Different translation units:

_localtime:
        ld      hl, -4
        call    __frameset
        ld      iy, (ix + 6)
        ld      hl, (iy)
        ld      a, (iy + 3)
        ld      (ix - 4), hl
        ld      (ix - 1), a
        pea     ix - 4
        call    _gmtime
        ld      sp, ix
        pop     ix
        ret
``