DMD optimization bug?

[Iain Buclaw]

On 21 March 2013 20:29, Jacob Carlborg <doob at me.com> wrote:

> The code below works fine without optimizations. But with optimizations
> (the -O flag) turned on it segfaults. The behavior with optimizations
> turned on is a bit different depending on which version of DMD I try and if
> I compile for 32 or 64bit.
>
> DMD 2.062 64bit: Segfault
> DMD 2.062 32bit: Prints a huge array then segfault
> DMD 2.061 64bit: Segfault
> DMD 2.061 32bit: Prints a fairly small array (10 elements) with random
> numbers
> DMD head (7dcc72a997) 32bit: Bus error: 10
>
> I'm using Mac OS X 10.8.2.
>
> import std.stdio;
>
> int[]* getDeserializedSlice ()
> {
>     void[] a = [1, 2, 3, 4, 5].dup;
>     auto b = &a;
>
>     if (auto c = b)
>         auto d = &(cast(int[]) *c)[1 .. 1 + 2];
>
>     return null;
> }
>
> void main ()
> {
>     writeln(*getDeserializedSlice(**));
> }
>
> Is the above code supposed to work? The test case might look a bit
> strange, the full source code is here:
>
> https://github.com/jacob-**carlborg/orange/blob/master/**
> orange/serialization/**Serializer.d#L1672<https://github.com/jacob-carlborg/orange/blob/master/orange/serialization/Serializer.d#L1672>
>
> --
> /Jacob Carlborg
>


As I see it, that code should *always* cause a segmentation fault.

You are returning 'null', and then dereferencing it...


Regards
-- 
Iain Buclaw

*(p < e ? p++ : p) = (c & 0x0f) + '0';
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