[Mesa-dev] [PATCH v2 3/6] nv50/ir: optimize IMAD to SHLADD in presence of power of 2

[Ilia Mirkin]

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

On Mon, Sep 26, 2016 at 5:02 PM, Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
> Only and only if src1 is a power of 2 we can replace IMAD by SHLADD.
>
> v2: - use non-negative values and use applyLog2()
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>  src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> index 74a5a85..c9d5b5f 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
> @@ -915,6 +915,7 @@ ConstantFolding::opnd3(Instruction *i, ImmediateValue &imm2)
>  void
>  ConstantFolding::opnd(Instruction *i, ImmediateValue &imm0, int s)
>  {
> +   const Target *target = prog->getTarget();
>     const int t = !s;
>     const operation op = i->op;
>     Instruction *newi = i;
> @@ -1016,6 +1017,12 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue &imm0, int s)
>           i->src(1).mod = i->src(2).mod;
>           i->setSrc(2, NULL);
>           i->op = OP_ADD;
> +      } else
> +      if (s == 1 && !imm0.isNegative() && imm0.isPow2() &&
> +          target->isOpSupported(i->op, i->dType)) {
> +         i->op = OP_SHLADD;
> +         imm0.applyLog2();
> +         i->setSrc(1, new_ImmediateValue(prog, imm0.reg.data.u32));
>        }
>        break;
>     case OP_ADD:
> --
> 2.10.0
>
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