That saved me so much work! I found the incorrect code - thanks Jonas!
Trunk:
...
mov x0,x22
bl SYSTEM_$$_NEWUNICODESTRING$INT64$$POINTER
mov x23,x0
lsl x2,x22,#1
mov x1,x23
cbnz x20,.Lj3808
adrp x20,:got:FPC_EMPTYCHAR
ldr x20,[x20, :got_lo12:FPC_EMPTYCHAR]
.Lj3808:
add x0,x20,x21,lsl #1
bl SYSTEM_$$_MOVE$formal$formal$INT64
stur x22,[x23, #-8]
...
Faulty optimisation:
...
mov x0,x22
bl SYSTEM_$$_NEWUNICODESTRING$INT64$$POINTER
// mov x23,0 gets removed because the optimiser thinks x23 is no longer
in use
lsl x2,x22,#1
mov x1,x0 (*) <-- x0 changed to x23
cbnz x20,.Lj3808
adrp x20,:got:FPC_EMPTYCHAR
ldr x20,[x20, :got_lo12:FPC_EMPTYCHAR]
.Lj3808:
add x0,x20,x21,lsl #1
bl SYSTEM_$$_MOVE$formal$formal$INT64
stur x22,[x23, #-8] <-- x23 is still in use (ERROR!)
...
Now I just have to work out why the peephole optimiser thinks x23 is no longer
in use after it
changes (*), and why it hasn't caused a more obvious failure elsewhere.
Gareth aka. Kit
On Sun 23/08/20 12:09 , "J. Gareth Moreton via fpc-devel"
fpc-devel@lists.freepascal.org sent:
> Thanks Jonas - I'll see if I can pinpoint it now.
>
>
>
> Gareth aka. Kit
>
>
>
> On Sun 23/08/20 13:09 , Jonas Maebe via fpc-devel
> fpc-devel@lists.freepascal.org sent:
> > On 23/08/2020 12:48, J. Gareth Moreton via
> fpc-devel wrote:
> >
>
> > > I've found a pretty big optimisation that
>
> > benefits most ARM platforms, including AArch64,
> but I'm getting a few
> > random test failures. My investigations suggest
> that functions like
> > "fpc_chararray_to_unicodestr" and
>
> > > other string conversion routines are not
> being
> > optimised properly (they're raising Runtime
> Error 216, which generally
> > implies a fatal exception). For aarch64 in
> particular, which unit contains
> > the source code or
>
> > > implementation for these functions?
>
> >
>
> >
>
> >
>
> > They're in the system unit (for all platforms).
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > Jonas
>
> >
>
> > _______________________________________________
>
> >
>
> > fpc-devel maillist - fpc-devel@lists.freepascal.org
> > https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
>
> >
>
> >
>
> >
>
> >
>
> >
>
>
>
> _______________________________________________
>
> fpc-devel maillist - fpc-devel@lists.freepascal.org
> https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
>
>
>
>
>
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