[Bug target/43676] New: [m68k] Wrong code due to missing sign extension

[nizze86 at hotmail dot com]

When compiling the following function for a coldfire target, such as mcf5249:
(using the following command line: m68k-elf-gcc saturate.c -mcpu=5249 -O1 -S)

int saturate(int x)
{
    return (x == (short)x ? x : (x >> 31) ^ 0x7FFF);
}

gcc produces:
saturate:
        link.w %fp,#0
        move.l 8(%fp),%d0
        move.w %d0,%a0
        cmp.l %a0,%d0
        jeq .L2
        add.l %d0,%d0
        subx.l %d0,%d0
        eor.l #32767,%d0
.L2:
        unlk %fp
        rts

Where a0 is compared to d0 without a sign extension so the upper half of a0
remtains whatever was already there.

This is with gcc:
4.5.0 20100401 (experimental) (GCC) 

configured with:
--target=m68k-elf --prefix=/usr/local --enable-languages=c --disable-libssp
--with-arch=cf --with-cpu=5249

Also observed with gcc 3.4.6 so likely not a regression.


-- 
           Summary: [m68k] Wrong code due to missing sign extension
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: nizze86 at hotmail dot com
GCC target triplet: m68k-elf-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43676