[Gambas-user] JIT bug 4

[Emil Lenngren]

Yes, "0.6 ^ x" was the culprit alone ;)

2012/7/10 Emil Lenngren <emil.lenngren at ...626...>

> Because if you only write "x = 0.6 ^ x", that statement is completely
> optimized away, because x is never used later on.
> If you write "Print 0.6 ^ x", the result of the operation is printed, i.e.
> used.
>
> If you write "Print 0.6 ^ 2", that is optimized to "Print 0.36".
>
> /Emil
>
>
> 2012/7/10 Jussi Lahtinen <jussi.lahtinen at ...626...>
>
>> Yes it works now.
>> But "Print 0.6 ^ x" did crash, but "x = 0.6 ^ x" alone did not crash
>> ("imMatr[10, 10] += x" was needed)!
>> So I wonder was "0.6 ^ x" culprit alone?
>>
>> Jussi
>>
>>
>>
>>
>> On 10 July 2012 18:13, Emil Lenngren <emil.lenngren at ...626...> wrote:
>>
>> > It should work now in revision #4934!
>> >
>> > /Emil
>> >
>> > 2012/7/9 Emil Lenngren <emil.lenngren at ...626...>
>> >
>> > > From gdb I disassemble the jit function to this:
>> > > ...
>> > >    0x00007ffff7e3f05c:  movabs $0x0,%rax
>> > >    0x00007ffff7e3f066:  callq  *%rax
>> > > ...
>> > >
>> > > You can see that llvm replaced the llvm.powi.f64 to a null function :/
>> > >
>> > > 2012/7/9 Emil Lenngren <emil.lenngren at ...626...>
>> > >
>> > >> Public Sub Button1_Click()
>> > >>   test(19)
>> > >> End
>> > >>
>> > >>
>> > >> Fast Private Sub test(x As Integer)
>> > >>   Print 0.6 ^ x
>> > >> End
>> > >>
>> > >> Does this crash for you as well?
>> > >>
>> > >> I think there is a bug in llvm or something. It doesn't seem to like
>> > that
>> > >> I call llvm.powi.f64.
>> > >>
>> > >> I shall see what I can do about it ...
>> > >>
>> > >> /Emil
>> > >>
>> > >> 2012/7/9 Jussi Lahtinen <jussi.lahtinen at ...626...>
>> > >>
>> > >>> In fact the function can be further reduced to:
>> > >>> c = CInt((0.6 ^ iEta) / sngCached[iEta])
>> > >>>
>> > >>> Jussi
>> > >>>
>> > >>>
>> > >>>
>> > >>> On 9 July 2012 21:02, Jussi Lahtinen <jussi.lahtinen at ...626...>
>> wrote:
>> > >>>
>> > >>> > Finally, here it is isolated. See attachment.
>> > >>> > I don't know why I didn't get it in first try, and yet, I'm not
>> sure
>> > >>> what
>> > >>> > is going on...
>> > >>> >
>> > >>> > Gambas 3 rev 4921 @ Xubuntu 12.04 64bit
>> > >>> >
>> > >>> > Jussi
>> > >>> >
>> > >>>
>> > >>>
>> >
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>> >
>> >
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>> Exclusive live event will cover all the ways today's security and
>> threat landscape has changed and how IT managers can respond. Discussions
>> will include endpoint security, mobile security and the latest in malware
>> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
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