[Mesa-dev] [PATCH 2/2] radeonsi: Use buffer_load intrinsics instead of llvm.SI.vs.load.input

[Marek Olšák]

On Wed, Nov 16, 2016 at 4:38 PM, Tom Stellard <tom at stellard.net> wrote:
> On Wed, Nov 16, 2016 at 11:13:45AM +0100, Nicolai Hähnle wrote:
>> Have you looked at the shader-db impact?
>>
>
> shader-db is mostly unchanged.  There are a few decreases in SGPR usage and
> code size, and a 4 byte increase in code size for one shader.
>
>> I do think we should eventually do this, but llvm.SI.vs.load.input is
>> ReadNone while llvm.amdgcn.buffer.load.* is only ReadOnly, so as long as we
>> can't teach LLVM properly about no-aliasing and speculability, there may be
>> performance regressions.
>>
>
> Ideally llvm.amdgcn.buffer.load.* would be ReadOnly and ArgMemOnly, but I think
> as long as it has non-pointer arguments this combination behaves the same as
> ReadNone, which would be incorrect.

Why would it be incorrect?

Marek