From: Dibyendu Majumdar <mobile@majumdar.org.uk>
To: David Malcolm <dmalcolm@redhat.com>
Cc: jit@gcc.gnu.org
Subject: Re: Filed PR jit/66812 for the code generation issue
Date: Thu, 01 Jan 2015 00:00:00 -0000 [thread overview]
Message-ID: <CACXZuxdP=W1dmW_=xoY2u60Wafku_oOtBfLPZP+rub2N_qrLhQ@mail.gmail.com> (raw)
In-Reply-To: <1436469764.24803.156.camel@surprise>
On 9 July 2015 at 20:22, David Malcolm <dmalcolm@redhat.com> wrote:
>> but it does seem to have caused
>> the optimization bug to go away - i.e. the tests now pass. I will run
>> more tests tomorrow to see if this is true under all optimization
>> settings.
>
> FWIW, I suspect that this is effectively just papering over the problem,
> and that it will come back to bite us, just with a more complicated
> reproducer :(
>
Yes agree.
> Does something like:
>
>
> function x(some_arg)
> local IX
> if ((some_arg or true) and false) then
> IX = true
> end;
> return ((some_arg or true) and false)
> end
> assert(x() == false)
>
>
>
> exhibit the bug? (have never programmed Lua, so this probably even
> isn't syntactically correct, but hopefully you get the idea, with
> const-propagation of 10's value and typecode lots of code gets optimized
> away, so using an arg of unknown type to thwart that and hopefully get
> the bug to re-manifest itself).
>
Actually that is valid Lua. Since you aren't passing a value to x()
then some_arg will be NIL. In Lua, NIL and false are false, everything
else is true.
The example above works okay as is, and also when I pass 10 to x().
As usual with certain bugs - only a specific set of circumstances trigger it.
>
> (Note that I've managed to isolate a minimal reproducer for the problem,
> as noted in another mail this thread)
>
Yes that is very good news. Hope you will soon discover the root cause.
Thanks and Regards
Dibyendu
next prev parent reply other threads:[~2015-07-09 20:53 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-01 0:00 A possible " Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Filed PR jit/66811: jit jumps aren't compilable as C (Re: A possible code generation issue) David Malcolm
2015-01-01 0:00 ` Filed PR jit/66811: jit dumps " David Malcolm
2015-01-01 0:00 ` A possible code generation issue Dibyendu Majumdar
2015-01-01 0:00 ` PR jit/66783 (Re: A possible code generation issue) David Malcolm
2015-01-01 0:00 ` [PATCH, committed] PR jit/66783: prevent use of opaque structs David Malcolm
2015-01-01 0:00 ` Filed PR jit/66812 for the code generation issue David Malcolm
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar [this message]
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` [PATCH] PR jit/66812: Candidate fix for for the code generation issue, v1 David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Filed PR jit/66812 for the code generation issue Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Dibyendu Majumdar
2015-01-01 0:00 ` Dibyendu Majumdar
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