[Mesa-dev] [PATCH v5] i965/fs: Handle non-const sample number in interpolateAtSample
Francisco Jerez
currojerez at riseup.net
Fri Oct 9 05:49:04 PDT 2015
Neil Roberts <neil at linux.intel.com> writes:
> If a non-const sample number is given to interpolateAtSample it will
> now generate an indirect send message with the sample ID similar to
> how non-const sampler array indexing works. Previously non-const
> values were ignored and instead it ended up using a constant 0 value.
>
> The generator will try to determine if the sample ID is dynamically
> uniform via nir_src_is_dynamically_uniform. If not it will query the
> pixel interpolator in a loop, once for each different live sample
> number. The next live sample number is found using emit_uniformize. If
> multiple live channels have the same sample number then they will be
> handled in a single iteration of the loop. The loop is necessary
> because the indirect send message doesn't seem to have a way to
> specify a different value for each fragment.
>
> This fixes the following two Piglit tests:
>
> arb_gpu_shader5-interpolateAtSample-nonconst
> arb_gpu_shader5-interpolateAtSample-dynamically-nonuniform
>
> v2: Handle dynamically non-uniform sample ids.
> v3: Remove the BREAK instruction and predicate the WHILE directly.
> Make the tokens arrays const. (Matt Turner)
> v4: Iterate over the live channels instead of each possible sample
> number.
> v5: Don't special case immediate values in
> brw_pixel_interpolator_query. Make a better wrapper for the
> function to set up the PI send instruction. Ensure that the SHL
> instructions are scalar. (Francisco Jerez).
> ---
>
> Many thanks to Francisco and Matt for the all the helpful feedback.
>
Thank you, looks pretty good to me:
Reviewed-by: Francisco Jerez <currojerez at riseup.net>
> src/mesa/drivers/dri/i965/brw_eu.h | 2 +-
> src/mesa/drivers/dri/i965/brw_eu_emit.c | 27 ++---
> src/mesa/drivers/dri/i965/brw_fs_generator.cpp | 5 +-
> src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 139 ++++++++++++++++++++-----
> 4 files changed, 130 insertions(+), 43 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_eu.h b/src/mesa/drivers/dri/i965/brw_eu.h
> index 761aa0e..0ac1ad9 100644
> --- a/src/mesa/drivers/dri/i965/brw_eu.h
> +++ b/src/mesa/drivers/dri/i965/brw_eu.h
> @@ -461,7 +461,7 @@ brw_pixel_interpolator_query(struct brw_codegen *p,
> struct brw_reg mrf,
> bool noperspective,
> unsigned mode,
> - unsigned data,
> + struct brw_reg data,
> unsigned msg_length,
> unsigned response_length);
>
> diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c b/src/mesa/drivers/dri/i965/brw_eu_emit.c
> index dc699bb..bf2fee9 100644
> --- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
> +++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
> @@ -3212,26 +3212,29 @@ brw_pixel_interpolator_query(struct brw_codegen *p,
> struct brw_reg mrf,
> bool noperspective,
> unsigned mode,
> - unsigned data,
> + struct brw_reg data,
> unsigned msg_length,
> unsigned response_length)
> {
> const struct brw_device_info *devinfo = p->devinfo;
> - struct brw_inst *insn = next_insn(p, BRW_OPCODE_SEND);
> -
> - brw_set_dest(p, insn, dest);
> - brw_set_src0(p, insn, mrf);
> - brw_set_message_descriptor(p, insn, GEN7_SFID_PIXEL_INTERPOLATOR,
> - msg_length, response_length,
> - false /* header is never present for PI */,
> - false);
> + struct brw_inst *insn;
> + const uint16_t exec_size = brw_inst_exec_size(devinfo, p->current);
>
> - brw_inst_set_pi_simd_mode(
> - devinfo, insn, brw_inst_exec_size(devinfo, insn) == BRW_EXECUTE_16);
> + /* brw_send_indirect_message will automatically use a direct send message
> + * if data is actually immediate.
> + */
> + insn = brw_send_indirect_message(p,
> + GEN7_SFID_PIXEL_INTERPOLATOR,
> + dest,
> + mrf,
> + vec1(data));
> + brw_inst_set_mlen(devinfo, insn, msg_length);
> + brw_inst_set_rlen(devinfo, insn, response_length);
> +
> + brw_inst_set_pi_simd_mode(devinfo, insn, exec_size == BRW_EXECUTE_16);
> brw_inst_set_pi_slot_group(devinfo, insn, 0); /* zero unless 32/64px dispatch */
> brw_inst_set_pi_nopersp(devinfo, insn, noperspective);
> brw_inst_set_pi_message_type(devinfo, insn, mode);
> - brw_inst_set_pi_message_data(devinfo, insn, data);
> }
>
> void
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
> index 6f8b75e..17e19cf 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
> @@ -1377,15 +1377,14 @@ fs_generator::generate_pixel_interpolator_query(fs_inst *inst,
> struct brw_reg msg_data,
> unsigned msg_type)
> {
> - assert(msg_data.file == BRW_IMMEDIATE_VALUE &&
> - msg_data.type == BRW_REGISTER_TYPE_UD);
> + assert(msg_data.type == BRW_REGISTER_TYPE_UD);
>
> brw_pixel_interpolator_query(p,
> retype(dst, BRW_REGISTER_TYPE_UW),
> src,
> inst->pi_noperspective,
> msg_type,
> - msg_data.dw1.ud,
> + msg_data,
> inst->mlen,
> inst->regs_written);
> }
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> index 03fe680..bc0df68 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> @@ -1180,6 +1180,36 @@ get_image_atomic_op(nir_intrinsic_op op, const glsl_type *type)
> }
> }
>
> +static fs_inst *
> +emit_pixel_interpolater_send(const fs_builder &bld,
> + enum opcode opcode,
> + const fs_reg &dst,
> + const fs_reg &src,
> + const fs_reg &desc,
> + glsl_interp_qualifier interpolation)
> +{
> + fs_inst *inst;
> + fs_reg payload;
> + int mlen;
> +
> + if (src.file == BAD_FILE) {
> + /* Dummy payload */
> + payload = bld.vgrf(BRW_REGISTER_TYPE_F, 1);
> + mlen = 1;
> + } else {
> + payload = src;
> + mlen = 2 * bld.dispatch_width() / 8;
> + }
> +
> + inst = bld.emit(opcode, dst, payload, desc);
> + inst->mlen = mlen;
> + /* 2 floats per slot returned */
> + inst->regs_written = 2 * bld.dispatch_width() / 8;
> + inst->pi_noperspective = interpolation == INTERP_QUALIFIER_NOPERSPECTIVE;
> +
> + return inst;
> +}
> +
> void
> fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr)
> {
> @@ -1583,28 +1613,81 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
> ((struct brw_wm_prog_data *) prog_data)->pulls_bary = true;
>
> fs_reg dst_xy = bld.vgrf(BRW_REGISTER_TYPE_F, 2);
> -
> - /* For most messages, we need one reg of ignored data; the hardware
> - * requires mlen==1 even when there is no payload. in the per-slot
> - * offset case, we'll replace this with the proper source data.
> - */
> - fs_reg src = vgrf(glsl_type::float_type);
> - int mlen = 1; /* one reg unless overriden */
> - fs_inst *inst;
> + const glsl_interp_qualifier interpolation =
> + (glsl_interp_qualifier) instr->variables[0]->var->data.interpolation;
>
> switch (instr->intrinsic) {
> case nir_intrinsic_interp_var_at_centroid:
> - inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_CENTROID,
> - dst_xy, src, fs_reg(0u));
> + emit_pixel_interpolater_send(bld,
> + FS_OPCODE_INTERPOLATE_AT_CENTROID,
> + dst_xy,
> + fs_reg(), /* src */
> + fs_reg(0u),
> + interpolation);
> break;
>
> case nir_intrinsic_interp_var_at_sample: {
> - /* XXX: We should probably handle non-constant sample id's */
> nir_const_value *const_sample = nir_src_as_const_value(instr->src[0]);
> - assert(const_sample);
> - unsigned msg_data = const_sample ? const_sample->i[0] << 4 : 0;
> - inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_SAMPLE, dst_xy, src,
> - fs_reg(msg_data));
> +
> + if (const_sample) {
> + unsigned msg_data = const_sample->i[0] << 4;
> +
> + emit_pixel_interpolater_send(bld,
> + FS_OPCODE_INTERPOLATE_AT_SAMPLE,
> + dst_xy,
> + fs_reg(), /* src */
> + fs_reg(msg_data),
> + interpolation);
> + } else {
> + const fs_reg sample_src = retype(get_nir_src(instr->src[0]),
> + BRW_REGISTER_TYPE_UD);
> +
> + if (nir_src_is_dynamically_uniform(instr->src[0])) {
> + const fs_reg sample_id = bld.emit_uniformize(sample_src);
> + const fs_reg msg_data = vgrf(glsl_type::uint_type);
> + bld.exec_all().group(1, 0).SHL(msg_data, sample_id, fs_reg(4u));
> + emit_pixel_interpolater_send(bld,
> + FS_OPCODE_INTERPOLATE_AT_SAMPLE,
> + dst_xy,
> + fs_reg(), /* src */
> + msg_data,
> + interpolation);
> + } else {
> + /* Make a loop that sends a message to the pixel interpolater
> + * for the sample number in each live channel. If there are
> + * multiple channels with the same sample number then these
> + * will be handled simultaneously with a single interation of
> + * the loop.
> + */
> + bld.emit(BRW_OPCODE_DO);
> +
> + /* Get the next live sample number into sample_id_reg */
> + const fs_reg sample_id = bld.emit_uniformize(sample_src);
> +
> + /* Set the flag register so that we can perform the send
> + * message on all channels that have the same sample number
> + */
> + bld.CMP(bld.null_reg_ud(),
> + sample_src, sample_id,
> + BRW_CONDITIONAL_EQ);
> + const fs_reg msg_data = vgrf(glsl_type::uint_type);
> + bld.exec_all().group(1, 0).SHL(msg_data, sample_id, fs_reg(4u));
> + fs_inst *inst =
> + emit_pixel_interpolater_send(bld,
> + FS_OPCODE_INTERPOLATE_AT_SAMPLE,
> + dst_xy,
> + fs_reg(), /* src */
> + msg_data,
> + interpolation);
> + set_predicate(BRW_PREDICATE_NORMAL, inst);
> +
> + /* Continue the loop if there are any live channels left */
> + set_predicate_inv(BRW_PREDICATE_NORMAL,
> + true, /* inverse */
> + bld.emit(BRW_OPCODE_WHILE));
> + }
> + }
> +
> break;
> }
>
> @@ -1615,10 +1698,14 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
> unsigned off_x = MIN2((int)(const_offset->f[0] * 16), 7) & 0xf;
> unsigned off_y = MIN2((int)(const_offset->f[1] * 16), 7) & 0xf;
>
> - inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_SHARED_OFFSET, dst_xy, src,
> - fs_reg(off_x | (off_y << 4)));
> + emit_pixel_interpolater_send(bld,
> + FS_OPCODE_INTERPOLATE_AT_SHARED_OFFSET,
> + dst_xy,
> + fs_reg(), /* src */
> + fs_reg(off_x | (off_y << 4)),
> + interpolation);
> } else {
> - src = vgrf(glsl_type::ivec2_type);
> + fs_reg src = vgrf(glsl_type::ivec2_type);
> fs_reg offset_src = retype(get_nir_src(instr->src[0]),
> BRW_REGISTER_TYPE_F);
> for (int i = 0; i < 2; i++) {
> @@ -1646,9 +1733,13 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
> bld.SEL(offset(src, bld, i), itemp, fs_reg(7)));
> }
>
> - mlen = 2 * dispatch_width / 8;
> - inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_PER_SLOT_OFFSET, dst_xy, src,
> - fs_reg(0u));
> + const enum opcode opcode = FS_OPCODE_INTERPOLATE_AT_PER_SLOT_OFFSET;
> + emit_pixel_interpolater_send(bld,
> + opcode,
> + dst_xy,
> + src,
> + fs_reg(0u),
> + interpolation);
> }
> break;
> }
> @@ -1657,12 +1748,6 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
> unreachable("Invalid intrinsic");
> }
>
> - inst->mlen = mlen;
> - /* 2 floats per slot returned */
> - inst->regs_written = 2 * dispatch_width / 8;
> - inst->pi_noperspective = instr->variables[0]->var->data.interpolation ==
> - INTERP_QUALIFIER_NOPERSPECTIVE;
> -
> for (unsigned j = 0; j < instr->num_components; j++) {
> fs_reg src = interp_reg(instr->variables[0]->var->data.location, j);
> src.type = dest.type;
> --
> 1.9.3
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