[Mesa-dev] [PATCH 4/9] anv/gen8_pipeline: Use Alternate floating point mode when use_alt_mode is set in prog_data

[Kenneth Graunke]

On Friday, September 30, 2016 3:33:12 PM PDT Anuj Phogat wrote:
> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> ---
>  src/intel/vulkan/gen8_pipeline.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/src/intel/vulkan/gen8_pipeline.c b/src/intel/vulkan/gen8_pipeline.c
> index 1abb97c..7a9a3cf 100644
> --- a/src/intel/vulkan/gen8_pipeline.c
> +++ b/src/intel/vulkan/gen8_pipeline.c
> @@ -197,7 +197,8 @@ genX(graphics_pipeline_create)(
>              vs_prog_data->base.base.binding_table.size_bytes / 4;
>  
>           vs.ThreadDispatchPriority        = false;
> -         vs.FloatingPointMode             = IEEE754;
> +         vs.FloatingPointMode             = vs_prog_data->base.base.use_alt_mode ?
> +                                            Alternate : IEEE754;
>           vs.IllegalOpcodeExceptionEnable  = false;
>           vs.AccessesUAV                   = false;
>           vs.SoftwareExceptionEnable       = false;
> 

I don't think we need this.  The only reason we use ALT mode is to make
the POW opcode match the ARB_fragment_program rules for 0^0.  Otherwise,
we always use IEEE-754.  We should always use IEEE for SPIR-V programs.
So, adding the condition just adds a tiny bit of CPU overhead.

How about we instead do:

   assert(!vs_prog_data->base.base.use_alt_mode);
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