[Mesa-dev] [PATCH] glsl: type check between switch init-expression and case

[Matt Turner]

On Mon, Jun 9, 2014 at 4:29 AM, Tapani Pälli <tapani.palli at intel.com> wrote:
> Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79724
> ---
>  src/glsl/ast_to_hir.cpp | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
> index d1c77f1..131b25f 100644
> --- a/src/glsl/ast_to_hir.cpp
> +++ b/src/glsl/ast_to_hir.cpp
> @@ -4629,6 +4629,15 @@ ast_case_label::hir(exec_list *instructions,
>           }
>        }
>
> +      /* Check that types match (no implicit conversions allowed). */

Good news. GLSL 4.30 updated the text to say (I think as a
clarification, so we should have this behavior always):

The type of the init-expression value in a switch statement must be a
scalar int or uint. The type of the constant-expression value in a case
label also must be a scalar int or uint. When any pair of these values
is tested for "equal value" and the types do not match, an implicit
conversion will be done to convert the int to a uint (see section 4.1.10
“Implicit Conversions”) before the compare is done.

Please replace this comment with that spec citation in our usual
format. I guess we'll need a little bit of code to handle implicit
conversions here, but apparently only for int -> uint which is a
relief.