[Mesa-dev] [PATCH 2/2] nir/opcodes: Don't go through doubles when constant-folding iabs

[Connor Abbott]

Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>

On Mon, Jan 26, 2015 at 12:43 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> Previously, we called the abs() function in math.h.  However, this involves
> unnecessarily going through double.  This commit changes it to use integers
> directly with a ternary.
> ---
>  src/glsl/nir/nir_opcodes.py | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/glsl/nir/nir_opcodes.py b/src/glsl/nir/nir_opcodes.py
> index 0fa8bf5..f54a017 100644
> --- a/src/glsl/nir/nir_opcodes.py
> +++ b/src/glsl/nir/nir_opcodes.py
> @@ -147,7 +147,7 @@ unop("inot", tint, "~src0") # invert every bit of the integer
>  unop("fnot", tfloat, "(src0 == 0.0f) ? 1.0f : 0.0f")
>  unop("fsign", tfloat, "(src0 == 0.0f) ? 0.0f : ((src0 > 0.0f) ? 1.0f : -1.0f)")
>  unop("isign", tint, "(src0 == 0) ? 0 : ((src0 > 0) ? 1 : -1)")
> -unop("iabs", tint, "abs(src0)")
> +unop("iabs", tint, "(src0 < 0) ? -src0 : src0")
>  unop("fabs", tfloat, "fabsf(src0)")
>  unop("fsat", tfloat, "(src0 > 1.0f) ? 1.0f : ((src0 <= 0.0f) ? 0.0f : src0)")
>  unop("frcp", tfloat, "1.0f / src0")
> --
> 2.2.1
>
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