[Mesa-dev] [Nouveau] [PATCH] nv50/ir: optimmize shl(a, 0) to a

[Samuel Pitoiset]

"optimmize" ? No need to resend just for that though.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>

On 04/29/2017 06:46 PM, Karol Herbst wrote:
> helps two alien isolation shaders
> 
> shader-db:
> total instructions in shared programs : 4251497 -> 4251494 (-0.00%)
> total gprs used in shared programs    : 513962 -> 513962 (0.00%)
> total local used in shared programs   : 29797 -> 29797 (0.00%)
> total bytes used in shared programs   : 38960264 -> 38960232 (-0.00%)
> 
>                  local        gpr       inst      bytes
>      helped           0           0           2           2
>        hurt           0           0           0           0
> 
> Signed-off-by: Karol Herbst <karolherbst at gmail.com>
> ---
>   src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> index 015def0391..a2446e4df8 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> @@ -1284,6 +1284,11 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue &imm0, int s)
>   
>      case OP_SHL:
>      {
> +      if (s == 1 && imm0.isInteger(0)) {
> +         i->op = OP_MOV;
> +         i->setSrc(1, NULL);
> +         break;
> +      }
>         if (s != 1 || i->src(0).mod != Modifier(0))
>            break;
>         // try to concatenate shifts
>