[Mesa-dev] [PATCH 2/3] radeonsi: implement PK2H and UP2H opcodes

[Marek Olšák]

On Sat, Jan 30, 2016 at 12:46 AM, Marek Olšák <maraeo at gmail.com> wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> Based on a gallivm patch by Ilia Mirkin.
>
> +8 piglit regressions due to precision issues
> ---
>  .../drivers/radeon/radeon_setup_tgsi_llvm.c        | 72 ++++++++++++++++++++++
>  src/gallium/drivers/radeonsi/si_pipe.c             |  2 +-
>  2 files changed, 73 insertions(+), 1 deletion(-)
>
> diff --git a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> index 76be376..d8e05ce 100644
> --- a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> +++ b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> @@ -1452,6 +1452,74 @@ static void emit_minmax_int(const struct lp_build_tgsi_action *action,
>                                 emit_data->args[1], "");
>  }
>
> +static void pk2h_fetch_args(struct lp_build_tgsi_context * bld_base,
> +                           struct lp_build_emit_data * emit_data)
> +{
> +       emit_data->args[0] = lp_build_emit_fetch(bld_base, emit_data->inst,
> +                                                0, TGSI_CHAN_X);
> +       emit_data->args[1] = lp_build_emit_fetch(bld_base, emit_data->inst,
> +                                                0, TGSI_CHAN_Y);
> +}
> +
> +static void emit_pk2h(const struct lp_build_tgsi_action *action,
> +                     struct lp_build_tgsi_context *bld_base,
> +                     struct lp_build_emit_data *emit_data)
> +{
> +       LLVMBuilderRef builder = bld_base->base.gallivm->builder;
> +       LLVMContextRef context = bld_base->base.gallivm->context;
> +       struct lp_build_context *uint_bld = &bld_base->uint_bld;
> +       LLVMTypeRef fp16, i16;
> +       LLVMValueRef const16, comp[2];
> +       unsigned i;
> +
> +       fp16 = LLVMHalfTypeInContext(context);
> +       i16 = LLVMInt16TypeInContext(context);
> +       const16 = lp_build_const_int32(uint_bld->gallivm, 16);
> +
> +       for (i = 0; i < 2; i++) {
> +               comp[i] = LLVMBuildFPTrunc(builder, emit_data->args[i], fp16, "");
> +               comp[i] = LLVMBuildBitCast(builder, comp[i], i16, "");
> +               comp[i] = LLVMBuildZExt(builder, comp[i], uint_bld->elem_type, "");
> +       }
> +
> +       comp[1] = LLVMBuildShl(builder, comp[1], const16, "");
> +       comp[0] = LLVMBuildOr(builder, comp[0], comp[1], "");
> +
> +       emit_data->output[emit_data->chan] = comp[0];
> +}
> +
> +static void up2h_fetch_args(struct lp_build_tgsi_context * bld_base,
> +                           struct lp_build_emit_data * emit_data)
> +{
> +       emit_data->args[0] = lp_build_emit_fetch(bld_base, emit_data->inst,
> +                                                0, TGSI_CHAN_X);
> +}
> +
> +static void emit_up2h(const struct lp_build_tgsi_action *action,
> +                     struct lp_build_tgsi_context *bld_base,
> +                     struct lp_build_emit_data *emit_data)
> +{
> +       LLVMBuilderRef builder = bld_base->base.gallivm->builder;
> +       LLVMContextRef context = bld_base->base.gallivm->context;
> +       struct lp_build_context *uint_bld = &bld_base->uint_bld;
> +       LLVMTypeRef fp16, i16;
> +       LLVMValueRef const16, input, val;
> +       unsigned i;
> +
> +       fp16 = LLVMHalfTypeInContext(context);
> +       i16 = LLVMInt16TypeInContext(context);
> +       const16 = lp_build_const_int32(uint_bld->gallivm, 16);
> +       input = emit_data->args[0];
> +
> +       for (i = 0; i < 2; i++) {
> +               val = i == 1 ? LLVMBuildLShr(builder, input, const16, "") : input;
> +               val = LLVMBuildTrunc(builder, val, i16, "");
> +               val = LLVMBuildBitCast(builder, val, fp16, "");
> +               emit_data->output[i] =
> +                       LLVMBuildFPExt(builder, val, bld_base->base.elem_type, "");
> +       }
> +}
> +
>  void radeon_llvm_context_init(struct radeon_llvm_context * ctx)
>  {
>         struct lp_type type;
> @@ -1581,6 +1649,8 @@ void radeon_llvm_context_init(struct radeon_llvm_context * ctx)
>         bld_base->op_actions[TGSI_OPCODE_UMSB].emit = emit_umsb;
>         bld_base->op_actions[TGSI_OPCODE_NOT].emit = emit_not;
>         bld_base->op_actions[TGSI_OPCODE_OR].emit = emit_or;
> +       bld_base->op_actions[TGSI_OPCODE_PK2H].fetch_args = pk2h_fetch_args;
> +       bld_base->op_actions[TGSI_OPCODE_PK2H].emit = emit_pk2h;
>         bld_base->op_actions[TGSI_OPCODE_POPC].emit = build_tgsi_intrinsic_nomem;
>         bld_base->op_actions[TGSI_OPCODE_POPC].intr_name = "llvm.ctpop.i32";
>         bld_base->op_actions[TGSI_OPCODE_POW].emit = build_tgsi_intrinsic_nomem;
> @@ -1618,6 +1688,8 @@ void radeon_llvm_context_init(struct radeon_llvm_context * ctx)
>         bld_base->op_actions[TGSI_OPCODE_U2F].emit = emit_u2f;
>         bld_base->op_actions[TGSI_OPCODE_XOR].emit = emit_xor;
>         bld_base->op_actions[TGSI_OPCODE_UCMP].emit = emit_ucmp;
> +       bld_base->op_actions[TGSI_OPCODE_UP2H].fetch_args = up2h_fetch_args;
> +       bld_base->op_actions[TGSI_OPCODE_UP2H].emit = emit_up2h;
>  }
>
>  void radeon_llvm_create_func(struct radeon_llvm_context * ctx,
> diff --git a/src/gallium/drivers/radeonsi/si_pipe.c b/src/gallium/drivers/radeonsi/si_pipe.c
> index 05f30bd..4dacdd1 100644
> --- a/src/gallium/drivers/radeonsi/si_pipe.c
> +++ b/src/gallium/drivers/radeonsi/si_pipe.c
> @@ -308,6 +308,7 @@ static int si_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
>         case PIPE_CAP_TGSI_FS_POSITION_IS_SYSVAL:
>         case PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL:
>         case PIPE_CAP_INVALIDATE_BUFFER:
> +       case PIPE_CAP_TGSI_PACK_HALF_FLOAT:
>                 return 1;

FYI, I'm going to change it to this:
return HAVE_LLVM >= 0x0306

because Roland said LLVM < 3.6 doesn't support fptrunc 32->16.

Alternatively, we can axe the LLVM 3.5 support code, which would clean
up our compute code paths, but not graphics code paths.

Marek