[Mesa-dev] [PATCH 1/5] meta: silence uninitialized variable warnings for MinGW

[Matt Turner]

On Fri, Feb 27, 2015 at 12:07 PM, Brian Paul <brianp at vmware.com> wrote:
> ---
>  src/mesa/drivers/common/meta_blit.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/src/mesa/drivers/common/meta_blit.c b/src/mesa/drivers/common/meta_blit.c
> index 971a2ff..bb21642 100644
> --- a/src/mesa/drivers/common/meta_blit.c
> +++ b/src/mesa/drivers/common/meta_blit.c
> @@ -133,6 +133,8 @@ setup_glsl_msaa_blit_scaled_shader(struct gl_context *ctx,
>        sample_map = ctx->Const.SampleMap8x;
>        break;
>     default:
> +      sample_number = NULL;
> +      sample_map = NULL;
>        _mesa_problem(ctx, "Unsupported sample count %d\n", samples);
>        unreachable("Unsupported sample count");
>     }
> --
> 1.9.1

For this to be a warning, you have to be using gcc from before 4.5
(support for __builtin_unreachable). How much do we want to, IMO,
clutter the code to avoid warnings on gcc that old?

If we really want to do better, I think we can implement unreachable()
on gcc < 4.5 with a small static inline function marked with the
noreturn attribute.