Re: draft execution environment for WebGPU, including WebGPU env spec for SPIR-V

After only 10 emails it's already hard to follow what are the separate
concerns and what has already been stated.. Can you please open one issue
per individual concern on https://github.com/gpuweb/spirv-execution-env? It
would help keep each discussion focused on a single concern and get to a
resolution/fix faster.

On Wed, Nov 14, 2018 at 8:36 PM Filip Pizlo <fpizlo@apple.com> wrote:

> It’s not great that to figure these things out, one must read multiple
> specs instead of one.
>
> -Filip
>
> On Nov 14, 2018, at 11:29 AM, Dan Sinclair <dsinclair@google.com> wrote:
>
> On Wed, Nov 14, 2018 at 1:52 PM Maciej Stachowiak <mjs@apple.com> wrote:
>
>> Consider OpUndef. The whole purpose of this instruction is to invoke an
>> undefined behavior for the sake of performance (since initializing may  be
>> costly when it’s not necessary). Does any shader program containing OpUndef
>> get rejected? Does it trap and halt? Does it return an arbitrary value that
>> is uninitialized and therefore may lead to reading stale data ? Does it
>> initialize to a specific known value (e.g. zero)?
>>
>>
> The env spec states:
>    OpUndef is not allowed.
>
> So, the shader would be rejected as invalid.
>
> dan
>
>

Received on Wednesday, 14 November 2018 21:13:10 UTC