[Mesa-dev] [PATCH 2/2] gm200/ir: optimize rcp(sqrt) to rsq

[Ilia Mirkin]

With the minor fix in 1/2, this series is

Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>

On Fri, Aug 3, 2018 at 10:52 PM, Karol Herbst <kherbst at redhat.com> wrote:
> mitigates hurt shaders after adding sqrt:
> total instructions in shared programs : 5456166 -> 5454825 (-0.02%)
> total gprs used in shared programs    : 647522 -> 647551 (0.00%)
> total shared used in shared programs  : 389120 -> 389120 (0.00%)
> total local used in shared programs   : 21064 -> 21064 (0.00%)
> total bytes used in shared programs   : 58288696 -> 58274448 (-0.02%)
>
>                 local     shared        gpr       inst      bytes
>     helped           0           0           0         516         516
>       hurt           0           0          27           2           2
>
> Signed-off-by: Karol Herbst <kherbst at redhat.com>
> ---
>  .../drivers/nouveau/codegen/nv50_ir_peephole.cpp      | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> index 16022e6f237..2f7cc206b84 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> @@ -1848,15 +1848,24 @@ AlgebraicOpt::handleMINMAX(Instruction *minmax)
>     }
>  }
>
> +// rcp(rcp(a)) = a
> +// rcp(sqrt(a)) = rsq(a)
>  void
>  AlgebraicOpt::handleRCP(Instruction *rcp)
>  {
>     Instruction *si = rcp->getSrc(0)->getUniqueInsn();
>
> -   if (si && si->op == OP_RCP) {
> +   if (!si)
> +      return;
> +
> +   if (si->op == OP_RCP) {
>        Modifier mod = rcp->src(0).mod * si->src(0).mod;
>        rcp->op = mod.getOp();
>        rcp->setSrc(0, si->getSrc(0));
> +   } else if (si->op == OP_SQRT) {
> +      rcp->op = OP_RSQ;
> +      rcp->setSrc(0, si->getSrc(0));
> +      rcp->src(0).mod = rcp->src(0).mod * si->src(0).mod;
>     }
>  }
>
> --
> 2.17.1
>
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