[Mesa-dev] [PATCH] gallivm: fix F2U opcode

[Zack Rusin]

Looks good.

Reviewed-by: Zack Rusin <zackr at vmware.com>

----- Original Message -----
> From: Roland Scheidegger <sroland at vmware.com>
> 
> Previously, we were really doing F2I. And also move it to generic section.
> (Note that for llvmpipe the code generated is definitely bad, due to lack
> of unsigned conversions with sse. I think though what llvm does (using scalar
> conversions to 64bit signed either with x87 fpu (32bit) or sse (64bit)
> including lots of domain changes is quite suboptimal, could do something like
> is_large = arg >= 2^31
> half_arg = 0.5 * arg
> small_c = fptoint(arg)
> large_c = fptoint(half_arg) << 1
> res = select(is_large, large_c, small_c)
> which should be much less instructions but that's something llvm should do
> itself.)
> 
> This fixes piglit fs/vs-float-uint-conversion.shader_test (maybe more, needs
> GL 3.0 version override to run.)
> ---
>  src/gallium/auxiliary/gallivm/lp_bld_tgsi_action.c |   42
>  ++++++++++----------
>  1 file changed, 22 insertions(+), 20 deletions(-)
> 
> diff --git a/src/gallium/auxiliary/gallivm/lp_bld_tgsi_action.c
> b/src/gallium/auxiliary/gallivm/lp_bld_tgsi_action.c
> index caaeb01..b9546db 100644
> --- a/src/gallium/auxiliary/gallivm/lp_bld_tgsi_action.c
> +++ b/src/gallium/auxiliary/gallivm/lp_bld_tgsi_action.c
> @@ -720,10 +720,23 @@ sub_emit(
>     struct lp_build_tgsi_context * bld_base,
>     struct lp_build_emit_data * emit_data)
>  {
> -	emit_data->output[emit_data->chan] = LLVMBuildFSub(
> -				bld_base->base.gallivm->builder,
> -				emit_data->args[0],
> -				emit_data->args[1], "");
> +   emit_data->output[emit_data->chan] =
> +      LLVMBuildFSub(bld_base->base.gallivm->builder,
> +                    emit_data->args[0],
> +                    emit_data->args[1], "");
> +}
> +
> +/* TGSI_OPCODE_F2U */
> +static void
> +f2u_emit(
> +   const struct lp_build_tgsi_action * action,
> +   struct lp_build_tgsi_context * bld_base,
> +   struct lp_build_emit_data * emit_data)
> +{
> +   emit_data->output[emit_data->chan] =
> +      LLVMBuildFPToUI(bld_base->base.gallivm->builder,
> +                      emit_data->args[0],
> +                      bld_base->base.int_vec_type, "");
>  }
>  
>  /* TGSI_OPCODE_U2F */
> @@ -733,9 +746,10 @@ u2f_emit(
>     struct lp_build_tgsi_context * bld_base,
>     struct lp_build_emit_data * emit_data)
>  {
> -   emit_data->output[emit_data->chan] =
> LLVMBuildUIToFP(bld_base->base.gallivm->builder,
> -							emit_data->args[0],
> -							bld_base->base.vec_type, "");
> +   emit_data->output[emit_data->chan] =
> +      LLVMBuildUIToFP(bld_base->base.gallivm->builder,
> +                      emit_data->args[0],
> +                      bld_base->base.vec_type, "");
>  }
>  
>  static void
> @@ -949,6 +963,7 @@ lp_set_default_actions(struct lp_build_tgsi_context *
> bld_base)
>     bld_base->op_actions[TGSI_OPCODE_SUB].emit = sub_emit;
>  
>     bld_base->op_actions[TGSI_OPCODE_UARL].emit = mov_emit;
> +   bld_base->op_actions[TGSI_OPCODE_F2U].emit = f2u_emit;
>     bld_base->op_actions[TGSI_OPCODE_U2F].emit = u2f_emit;
>     bld_base->op_actions[TGSI_OPCODE_UMAD].emit = umad_emit;
>     bld_base->op_actions[TGSI_OPCODE_UMUL].emit = umul_emit;
> @@ -1128,18 +1143,6 @@ f2i_emit_cpu(
>                                                          emit_data->args[0]);
>  }
>  
> -/* TGSI_OPCODE_F2U (CPU Only) */
> -static void
> -f2u_emit_cpu(
> -   const struct lp_build_tgsi_action * action,
> -   struct lp_build_tgsi_context * bld_base,
> -   struct lp_build_emit_data * emit_data)
> -{
> -   /* FIXME: implement and use lp_build_utrunc() */
> -   emit_data->output[emit_data->chan] = lp_build_itrunc(&bld_base->base,
> -                                                        emit_data->args[0]);
> -}
> -
>  /* TGSI_OPCODE_FSET Helper (CPU Only) */
>  static void
>  fset_emit_cpu(
> @@ -1832,7 +1835,6 @@ lp_set_default_actions_cpu(
>     bld_base->op_actions[TGSI_OPCODE_DIV].emit = div_emit_cpu;
>     bld_base->op_actions[TGSI_OPCODE_EX2].emit = ex2_emit_cpu;
>     bld_base->op_actions[TGSI_OPCODE_F2I].emit = f2i_emit_cpu;
> -   bld_base->op_actions[TGSI_OPCODE_F2U].emit = f2u_emit_cpu;
>     bld_base->op_actions[TGSI_OPCODE_FLR].emit = flr_emit_cpu;
>     bld_base->op_actions[TGSI_OPCODE_FSEQ].emit = fseq_emit_cpu;
>     bld_base->op_actions[TGSI_OPCODE_FSGE].emit = fsge_emit_cpu;
> --
> 1.7.9.5
>