Re: DMD CTFE Bug?

[David]

Am 17.08.2012 18:36, schrieb Dmitry Olshansky:

On 17-Aug-12 20:27, David wrote:

I have this code: http://dpaste.dzfl.pl/dbe2a07f

It works perfectly fine, except for `t!(2, 10)` and `t!(1, 10)`:

// Expected:
[Vertex(-0.5, 0.5, 0.5, 0, 1, 0, 2, 10, 2, 10, 0, 0), Vertex(0.5, 0.5,
0.5, 0, 1, 0, 3, 10, 3, 10, 0, 0), Vertex(0.5,  0.5, -0.5, 0,  1, 0, 3,
9, 3, 9, 0, 0),
  Vertex(-0.5, 0.5, 0.5, 0, 1, 0, 2, 10, 2, 10, 0, 0), Vertex(0.5, 0.5,
-0.5, 0, 1, 0, 3, 9, 3, 9, 0, 0), Vertex(-0.5, 0.5, -0.5, 0, 1, 0, 2, 9,
2, 9, 0, 0)]

// Actual result:
[Vertex(-0.5, 0.5, 0.5, 0, 1, 0, 2, 10, 2, 10, 0, 0), Vertex(0.5, 0.5,
0.5, 0, 1, 0, 3, 10, 3, 10, 0, 0), Vertex(0.5, -0.5,  0.5, 0, -1, 0, 6,
3, 6, 3, 0, 0),
  Vertex(-0.5, 0.5, 0.5, 0, 1, 0, 2, 10, 2, 10, 0, 0), Vertex(0.5, 0.5,
-0.5, 0, 1, 0, 3, 9, 3, 9, 0, 0), Vertex(-0.5, 0.5, -0.5, 0, 1, 0, 2, 9,
2, 9, 0, 0)]

If I change `enum` in line 117 to `auto` it produces the expected result.

Any ideas why this happens?

Bug. There is no excuse for compiler to get different result during CTFE.

Great ...

(Btw. I wasn't able produce a smaller testcase)

It's not thousands of lines either. But where does Vertex type comes from?

struct Vertex {
    float x;
    float y;
    float z;
    float nx;
    float ny;
    float nz;
    byte u_terrain;
    byte v_terrain;
    byte u_mask;
    byte v_mask;
    float u_biome;
    float v_biome;
}