ctfe bug?

[Jacob Carlborg]

On 2011-12-22 08:47, Johannes Pfau wrote:
> Hi,
> the following code is reduced from a parser generated with Ragel
> (http://www.complang.org/ragel/). That's also the reason why it's
> using pointers instead of array access, but Ragel guarantees that there
> won't be any out-of-bound reads.
>
> AFAIK pointers are supported in CTFE now as long as they're pointing to an
> array and there are no out-of-bounds reads. Still, the following code fails:
>
> --------------------
> ubyte[4] testCTFE()
> {
>      ubyte[4] data;
>      string input = "8ab3060e2cba4f23b74cb52db3bdfb46";
>      auto p = input.ptr;
>      p++; p++;
>      data[0] = parse!ubyte((p-2)[0 .. 2], 16);
>      p++; p++;
>      data[1] = parse!ubyte((p-2)[0 .. 2], 16);
>      p++; p++;
>      data[2] = parse!ubyte((p-2)[0 .. 2], 16);
>      p++; p++;
>      data[3] = parse!ubyte((p-2)[0 .. 2], 16);
>      p++; p++;
>      return data;
> }
> enum ctfe = testCTFE();
>
> void main()
> {
> 	import std.stdio;
> 	writeln(testCTFE()); //[138, 179, 6, 14]
> 	writeln(ctfe); //[138, 138, 138, 138]
> }
> --------------------
>
> Has this bug already been filed? I could possibly circumvent it by making
> ragel use array indexing instead of pointers, but that'd be a performance
> issue for runtime code as well.

Why would arrays be slower than pointers? You do know that you can turn 
off array bounds checking?

-- 
/Jacob Carlborg