Giovanni Mascellani (@giomasce) commented about libs/vkd3d-shader/dxil.c:
++block_idx; code_block = (block_idx < function->block_count) ? function->blocks[block_idx] : NULL;
This was already here before, but I just realized that setting `code_block` to `NULL` might give a few problems if there are some other instructions (which shouldn't be there, but the shader might be untrusted input). Specifically, various lines in this loop assume that `code_block` is valid, and if it's not an `assert()` could be triggered.