[Mesa-dev] [PATCH] nir: Avoid an extra NIR op in integer divide lowering.

[Kenneth Graunke]

On Monday, November 7, 2016 12:28:34 PM PST Eric Anholt wrote:
> NIR bools are ~0 for true, so ((unsigned)a >> 31) != 0 -> ((int)a >> 31).
> ---
>  src/compiler/nir/nir_lower_idiv.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/src/compiler/nir/nir_lower_idiv.c b/src/compiler/nir/nir_lower_idiv.c
> index b1e7aeb03c8a..6726b718aaa5 100644
> --- a/src/compiler/nir/nir_lower_idiv.c
> +++ b/src/compiler/nir/nir_lower_idiv.c
> @@ -101,8 +101,7 @@ convert_instr(nir_builder *bld, nir_alu_instr *alu)
>     if (is_signed)  {
>        /* fix the sign: */
>        r = nir_ixor(bld, numer, denom);
> -      r = nir_ushr(bld, r, nir_imm_int(bld, 31));
> -      r = nir_i2b(bld, r);
> +      r = nir_ishr(bld, r, nir_imm_int(bld, 31));
>        b = nir_ineg(bld, q);
>        q = nir_bcsel(bld, r, b, q);
>     }
> 

Yep.

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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