[Bug c/42522] New: [m68k] Wrong code generated with -O2/-O3

["ami_stuff at o2 dot pl" <gcc-bugzilla@gcc.gnu.org>]

Hi,

This is a code from "libavformat/flvdec.c":

static int flv_probe(AVProbeData *p)
{
    const uint8_t *d;

    d = p->buf;
    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0 &&
AV_RB32(d+5)>8) {
        return AVPROBE_SCORE_MAX;
    }
    return 0;
}

When I compile FFmpeg with -O2/-O3 options, FFmpeg doesn't recognize FLV files
("Unknown format"), but when I use -O1 everything works correctly.

Here is asm output when I compile flvdec.c file with -O2:

_flv_probe:
        clr.l d0
        rts
        .even

and here when I use -O1:

_flv_probe:
        move.l 4(sp),a0
        move.l 4(a0),a0
        cmp.b #70,(a0)
        jne L3
        cmp.b #76,1(a0)
        jne L4
        cmp.b #86,2(a0)
        jne L5
        cmp.b #4,3(a0)
        jhi L6
        tst.b 5(a0)
        jne L7
        move.l 5(a0),d0
        moveq #8,d1
        cmp.l d0,d1
        jcs L8
        clr.l d0
        rts
L3:
        clr.l d0
        rts
L4:
        clr.l d0
        rts
L5:
        clr.l d0
        rts
L6:
        clr.l d0
        rts
L7:
        clr.l d0
        rts
L8:
        moveq #100,d0
        rts
        .even


I attache proprocessed files + asm output in the archive.


-- 
           Summary: [m68k] Wrong code generated with -O2/-O3
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ami_stuff at o2 dot pl
  GCC host triplet: i686-cygwin
GCC target triplet: m68k-amigaos


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42522