[Mesa-dev] [PATCH 11/15] i965/fs: If emit a MOV instead of a SEL if the sources are the same.

[Paul Berry]

On 28 October 2013 11:31, Matt Turner <mattst88 at gmail.com> wrote:

> total instructions in shared programs: 1287488 -> 1287457 (-0.00%)
> instructions in affected programs:     1745 -> 1714 (-1.78%)
> ---
>  src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp | 38
> +++++++++++++----------
>  1 file changed, 21 insertions(+), 17 deletions(-)
>

Patch subject should be "i965/fs: Emit a MOV instead of a SEL if the
sources are the same." (you had an extraneous "if").

With that change, patch is:

Reviewed-by: Paul Berry <stereotype441 at gmail.com>


>
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
> b/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
> index 8638f43..4c0eba9 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
> @@ -224,26 +224,30 @@ fs_visitor::opt_peephole_sel()
>              break;
>           }
>
> -         /* Only the last source register can be a constant, so if the
> MOV in
> -          * the "then" clause uses a constant, we need to put it in a
> -          * temporary.
> -          */
> -         fs_reg src0(then_mov[i]->src[0]);
> -         if (src0.file == IMM) {
> -            src0 = fs_reg(this, glsl_type::float_type);
> -            src0.type = then_mov[i]->src[0].type;
> -            mov_imm_inst[i] = MOV(src0, then_mov[i]->src[0]);
> -         }
> +         if (!then_mov[i]->src[0].equals(else_mov[i]->src[0])) {
> +            /* Only the last source register can be a constant, so if the
> MOV
> +             * in the "then" clause uses a constant, we need to put it in
> a
> +             * temporary.
> +             */
> +            fs_reg src0(then_mov[i]->src[0]);
> +            if (src0.file == IMM) {
> +               src0 = fs_reg(this, glsl_type::float_type);
> +               src0.type = then_mov[i]->src[0].type;
> +               mov_imm_inst[i] = MOV(src0, then_mov[i]->src[0]);
> +            }
>
> -         sel_inst[i] = SEL(then_mov[i]->dst, src0, else_mov[i]->src[0]);
> +            sel_inst[i] = SEL(then_mov[i]->dst, src0,
> else_mov[i]->src[0]);
>
> -         if (brw->gen == 6 && if_inst->conditional_mod) {
> -            /* For Sandybridge with IF with embedded comparison */
> -            sel_inst[i]->predicate = BRW_PREDICATE_NORMAL;
> +            if (brw->gen == 6 && if_inst->conditional_mod) {
> +               /* For Sandybridge with IF with embedded comparison */
> +               sel_inst[i]->predicate = BRW_PREDICATE_NORMAL;
> +            } else {
> +               /* Separate CMP and IF instructions */
> +               sel_inst[i]->predicate = if_inst->predicate;
> +               sel_inst[i]->predicate_inverse =
> if_inst->predicate_inverse;
> +            }
>           } else {
> -            /* Separate CMP and IF instructions */
> -            sel_inst[i]->predicate = if_inst->predicate;
> -            sel_inst[i]->predicate_inverse = if_inst->predicate_inverse;
> +            sel_inst[i] = MOV(then_mov[i]->dst, then_mov[i]->src[0]);
>           }
>
>           bb_progress = true;
> --
> 1.8.3.2
>
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