Hello,
On Mon, 26 Aug 2024, Paul Koning wrote:
> >>> 550: [--sp] = 0 sp_off = 0 {pushexthisi_const}
> >>> 551: [--sp] = 37 sp_off = -4 {pushexthisi_const}
> >>> 552: [--sp] = r37 sp_off = -8 {movsi_m68k2}
> >>> 554: [--sp] = r116 - r37 sp_off = -12 {subsi3}
> >>> 556: call sp_off = -16
> >>>
> >>> insn 554 doesn't match its constraints and needs some reloads:
> >>
> >> I think you're right in that the current code isn't correct, but the
> >> natural question is how in the world has this worked to-date. Though I
> >> guess targets which push arguments are a dying breed (though I would
> >> have expected i386 to have tripped over this at some point).
> >
> > Yeah, I wondered as well. For things to go wrong some instructions that
> > contain pre/post-inc/dec of the stack pointer need to have reloads in such
> > a way that the actual SP-change sideeffect moves to a different
> > instruction.
>
> I think I've seen that in the past on PDP11, and reported it, but I
> thought that particular issue was fixed not too long after.
Do you have a reference handy? I'd like to take a look, if for nothing
else than curiosity ;-)
Ciao,
Michael.
