[Mesa-dev] [PATCH v3 2/2] i965/fs: Handle non-const sample number in interpolateAtSample
Neil Roberts
neil at linux.intel.com
Mon Oct 5 06:29:45 PDT 2015
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 possible sample number.
This is necessary because the indirect send message doesn't seem to
have a way to specify a different value for each fragment.
The range of possible sample numbers is determined using
STATE_NUM_SAMPLES. When linking the shader it will now add a reference
to this state if any dynamically non-uniform calls to
interpolateAtSample are found.
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.
---
All three patches are also available in a branch here:
https://github.com/bpeel/mesa/tree/wip/nonconst-interpolate-at-sample
src/mesa/drivers/dri/i965/brw_eu.h | 2 +-
src/mesa/drivers/dri/i965/brw_eu_emit.c | 34 ++++---
src/mesa/drivers/dri/i965/brw_fs_generator.cpp | 5 +-
src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 127 +++++++++++++++++++++----
src/mesa/drivers/dri/i965/brw_program.c | 54 +++++++++++
src/mesa/drivers/dri/i965/brw_program.h | 1 +
src/mesa/drivers/dri/i965/brw_shader.cpp | 2 +
7 files changed, 193 insertions(+), 32 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..9c38e99 100644
--- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
@@ -3212,26 +3212,38 @@ 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);
+ struct brw_inst *insn;
+ uint16_t exec_size;
- 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);
+ if (data.file == BRW_IMMEDIATE_VALUE) {
+ 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);
+ brw_inst_set_pi_message_data(devinfo, insn, data.dw1.ud);
+ } else {
+ 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, brw_inst_exec_size(devinfo, insn) == BRW_EXECUTE_16);
+ exec_size = brw_inst_exec_size(devinfo, p->current);
+ 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..0625e44 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -1180,6 +1180,47 @@ get_image_atomic_op(nir_intrinsic_op op, const glsl_type *type)
}
}
+/* 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.
+ */
+static void
+setup_pixel_interpolater_instruction(fs_visitor *v,
+ nir_intrinsic_instr *instr,
+ fs_inst *inst,
+ int mlen = 1)
+{
+ inst->mlen = mlen;
+ /* 2 floats per slot returned */
+ inst->regs_written = 2 * v->dispatch_width / 8;
+ inst->pi_noperspective = instr->variables[0]->var->data.interpolation ==
+ INTERP_QUALIFIER_NOPERSPECTIVE;
+}
+
+static fs_reg
+get_num_samples_reg(fs_visitor *v)
+{
+ struct gl_program_parameter_list *params = v->prog->Parameters;
+ static const gl_state_index tokens[STATE_LENGTH] = {
+ STATE_NUM_SAMPLES
+ };
+ GLuint index = _mesa_add_state_reference(params, tokens);
+ unsigned i;
+
+ /* Try to find an existing copy of the uniform */
+ for (i = 0; i < v->uniforms; i++) {
+ if (v->stage_prog_data->param[i] ==
+ &v->prog->Parameters->ParameterValues[index][0])
+ goto found;
+ }
+
+ v->stage_prog_data->param[v->uniforms++] =
+ &v->prog->Parameters->ParameterValues[index][0];
+
+found:
+ return retype(fs_reg(UNIFORM, i), BRW_REGISTER_TYPE_UD);
+}
+
void
fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr)
{
@@ -1584,27 +1625,81 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
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;
switch (instr->intrinsic) {
case nir_intrinsic_interp_var_at_centroid:
inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_CENTROID,
dst_xy, src, fs_reg(0u));
+ setup_pixel_interpolater_instruction(this, instr, inst);
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;
+
+ inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_SAMPLE, dst_xy, src,
+ fs_reg(msg_data));
+
+ setup_pixel_interpolater_instruction(this, instr, inst);
+ } else {
+ fs_reg sample_src = retype(get_nir_src(instr->src[0]),
+ BRW_REGISTER_TYPE_UD);
+ fs_reg sample_id_reg;
+
+ if (nir_src_is_dynamically_uniform(instr->src[0])) {
+ sample_id_reg = vgrf(glsl_type::uint_type);
+ bld.SHL(sample_id_reg, sample_src, fs_reg(4u));
+ sample_id_reg = bld.emit_uniformize(sample_id_reg);
+ inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_SAMPLE, dst_xy, src,
+ sample_id_reg);
+ setup_pixel_interpolater_instruction(this, instr, inst);
+ } else {
+ /* Make a loop that sends a message to the pixel interpolator
+ * for each possible sample number so that each individual
+ * message will be dynamically uniform. The number of samples
+ * is determined by accessing the STATE_NUM_SAMPLES state var.
+ */
+ fs_reg i_reg = vgrf(glsl_type::uint_type);
+ fs_reg sample_id_reg = vgrf(glsl_type::uint_type);
+ fs_reg num_samples_reg = get_num_samples_reg(this);
+
+ bld.ADD(retype(i_reg, BRW_REGISTER_TYPE_D),
+ retype(num_samples_reg, BRW_REGISTER_TYPE_D),
+ fs_reg(-1));
+
+ bld.emit(BRW_OPCODE_DO);
+
+ bld.CMP(bld.null_reg_ud(),
+ sample_src, i_reg,
+ BRW_CONDITIONAL_EQ);
+ bld.IF(BRW_PREDICATE_NORMAL);
+ bld.SHL(sample_id_reg, i_reg, fs_reg(4u));
+ sample_id_reg = bld.emit_uniformize(sample_id_reg);
+ inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_SAMPLE, dst_xy, src,
+ sample_id_reg);
+ setup_pixel_interpolater_instruction(this, instr, inst);
+ bld.emit(BRW_OPCODE_ENDIF);
+
+ /* The conditional flag on instructions other than CMP* compare
+ * the *result* of the operation to zero rather than comparing
+ * the two sources.
+ */
+ set_condmod(BRW_CONDITIONAL_GE,
+ bld.ADD(retype(i_reg, BRW_REGISTER_TYPE_D),
+ retype(i_reg, BRW_REGISTER_TYPE_D),
+ fs_reg(-1)));
+
+ /* The predicate means that the loop will continue if i is now
+ * >= 0
+ */
+ set_predicate(BRW_PREDICATE_NORMAL, bld.emit(BRW_OPCODE_WHILE));
+ }
+ }
+
break;
}
@@ -1617,6 +1712,7 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
inst = bld.emit(FS_OPCODE_INTERPOLATE_AT_SHARED_OFFSET, dst_xy, src,
fs_reg(off_x | (off_y << 4)));
+ setup_pixel_interpolater_instruction(this, instr, inst);
} else {
src = vgrf(glsl_type::ivec2_type);
fs_reg offset_src = retype(get_nir_src(instr->src[0]),
@@ -1646,9 +1742,12 @@ 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));
+ setup_pixel_interpolater_instruction(this,
+ instr,
+ inst,
+ 2 * dispatch_width / 8);
}
break;
}
@@ -1657,12 +1756,6 @@ 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;
diff --git a/src/mesa/drivers/dri/i965/brw_program.c b/src/mesa/drivers/dri/i965/brw_program.c
index a034dac..2d7966c 100644
--- a/src/mesa/drivers/dri/i965/brw_program.c
+++ b/src/mesa/drivers/dri/i965/brw_program.c
@@ -144,6 +144,8 @@ brwProgramStringNotify(struct gl_context *ctx,
prog->nir = brw_create_nir(brw, NULL, prog, MESA_SHADER_FRAGMENT, true);
+ brw_add_interpolate_at_sample_params(prog);
+
brw_fs_precompile(ctx, NULL, prog);
break;
}
@@ -242,6 +244,58 @@ brw_add_texrect_params(struct gl_program *prog)
}
}
+static bool
+find_interpolate_at_sample_in_block(nir_block *block,
+ void *data)
+{
+ nir_foreach_instr(block, instr) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intrinsic_instr = nir_instr_as_intrinsic(instr);
+
+ if (intrinsic_instr->intrinsic != nir_intrinsic_interp_var_at_sample)
+ continue;
+
+ /* If the sample number is known to be dynamically uniform then
+ * the generator won't need the num_samples state.
+ */
+ if (nir_src_is_dynamically_uniform(intrinsic_instr->src[0]))
+ continue;
+
+ return false;
+ }
+
+ return true;
+}
+
+void
+brw_add_interpolate_at_sample_params(struct gl_program *prog)
+{
+ static const gl_state_index tokens[STATE_LENGTH] = {
+ STATE_NUM_SAMPLES
+ };
+
+ if (!prog->nir)
+ return;
+
+ /* If anything calls interpolateAtSample with a dynamically non-uniform
+ * sample ID then we need STATE_NUM_SAMPLES to be able to iterate over
+ * each possible value.
+ */
+ nir_foreach_overload(prog->nir, overload) {
+ if (overload->impl) {
+ bool found = !nir_foreach_block(overload->impl,
+ find_interpolate_at_sample_in_block,
+ ralloc_parent(overload->impl));
+ if (found) {
+ _mesa_add_state_reference(prog->Parameters, tokens);
+ break;
+ }
+ }
+ }
+}
+
/* Per-thread scratch space is a power-of-two multiple of 1KB. */
int
brw_get_scratch_size(int size)
diff --git a/src/mesa/drivers/dri/i965/brw_program.h b/src/mesa/drivers/dri/i965/brw_program.h
index cf0522a..d68eecc 100644
--- a/src/mesa/drivers/dri/i965/brw_program.h
+++ b/src/mesa/drivers/dri/i965/brw_program.h
@@ -164,6 +164,7 @@ bool brw_debug_recompile_sampler_key(struct brw_context *brw,
const struct brw_sampler_prog_key_data *old_key,
const struct brw_sampler_prog_key_data *key);
void brw_add_texrect_params(struct gl_program *prog);
+void brw_add_interpolate_at_sample_params(struct gl_program *prog);
void
brw_mark_surface_used(struct brw_stage_prog_data *prog_data,
diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
index 7bc080b..1e98881 100644
--- a/src/mesa/drivers/dri/i965/brw_shader.cpp
+++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
@@ -388,6 +388,8 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
prog->nir = brw_create_nir(brw, shProg, prog, (gl_shader_stage) stage,
is_scalar_shader_stage(compiler, stage));
+ brw_add_interpolate_at_sample_params(prog);
+
_mesa_reference_program(ctx, &prog, NULL);
}
--
1.9.3
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