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i965/fs: Don't renumber UNIFORM registers.

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Previously, remove_dead_constants() would renumber the UNIFORM registers
to be sequential starting from zero, and the resulting register number
would be used directly as an index into the params[] array.

This renumbering made it difficult to collect and save information about
pull constant locations, since setup_pull_constants() and
move_uniform_array_access_to_pull_constants() used different names.

This patch generalizes setup_pull_constants() to decide whether each
uniform register should be a pull constant, push constant, or neither
(because it's unused).  Then, it stores mappings from UNIFORM register
numbers to params[] or pull_params[] indices in the push_constant_loc
and pull_constant_loc arrays.  (We already did this for pull constants.)

Then, assign_curb_setup() just needs to consult the push_constant_loc
array to get the real index into the params[] array.

This effectively folds all the remove_dead_constants() functionality
into assign_constant_locations(), while being less irritable to work
with.

v2: Add assert(remapped <= i), requested by Topi.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
This commit is contained in:
Kenneth Graunke 2014-03-11 14:35:27 -07:00
parent d9f339eccd
commit 542f2e47f2
3 changed files with 86 additions and 118 deletions
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188
src/mesa/drivers/dri/i965/brw_fs.cpp
View file

@ -885,8 +885,8 @@ fs_visitor::import_uniforms(fs_visitor *v)
hash_table_call_foreach(v->variable_ht,
import_uniforms_callback,
variable_ht);
this->params_remap = v->params_remap;
this->nr_params_remap = v->nr_params_remap;
this->push_constant_loc = v->push_constant_loc;
this->uniforms = v->uniforms;
}
/* Our support for uniforms is piggy-backed on the struct
@ -1397,11 +1397,8 @@ fs_visitor::assign_curb_setup()
{
if (dispatch_width == 8) {
c->prog_data.first_curbe_grf = c->nr_payload_regs;
stage_prog_data->nr_params = uniforms;
} else {
c->prog_data.first_curbe_grf_16 = c->nr_payload_regs;
/* Make sure we didn't try to sneak in an extra uniform */
assert(uniforms == 0);
}
c->prog_data.curb_read_length = ALIGN(stage_prog_data->nr_params, 8) / 8;
@ -1412,7 +1409,19 @@ fs_visitor::assign_curb_setup()
for (unsigned int i = 0; i < 3; i++) {
if (inst->src[i].file == UNIFORM) {
int constant_nr = inst->src[i].reg + inst->src[i].reg_offset;
int uniform_nr = inst->src[i].reg + inst->src[i].reg_offset;
int constant_nr;
if (uniform_nr >= 0 && uniform_nr < (int) uniforms) {
constant_nr = push_constant_loc[uniform_nr];
} else {
/* Section 5.11 of the OpenGL 4.1 spec says:
* "Out-of-bounds reads return undefined values, which include
* values from other variables of the active program or zero."
* Just return the first push constant.
*/
constant_nr = 0;
}
struct brw_reg brw_reg = brw_vec1_grf(c->nr_payload_regs +
constant_nr / 8,
constant_nr % 8);
@ -1724,94 +1733,6 @@ fs_visitor::compact_virtual_grfs()
}
}
bool
fs_visitor::remove_dead_constants()
{
if (dispatch_width == 8) {
this->params_remap = ralloc_array(mem_ctx, int, uniforms);
this->nr_params_remap = uniforms;
for (unsigned int i = 0; i < uniforms; i++)
this->params_remap[i] = -1;
/* Find which params are still in use. */
foreach_list(node, &this->instructions) {
fs_inst *inst = (fs_inst *)node;
for (int i = 0; i < 3; i++) {
int constant_nr = inst->src[i].reg + inst->src[i].reg_offset;
if (inst->src[i].file != UNIFORM)
continue;
/* Section 5.11 of the OpenGL 4.3 spec says:
*
* "Out-of-bounds reads return undefined values, which include
* values from other variables of the active program or zero."
*/
if (constant_nr < 0 || constant_nr >= (int)uniforms) {
constant_nr = 0;
}
/* For now, set this to non-negative. We'll give it the
* actual new number in a moment, in order to keep the
* register numbers nicely ordered.
*/
this->params_remap[constant_nr] = 0;
}
}
/* Figure out what the new numbers for the params will be. At some
* point when we're doing uniform array access, we're going to want
* to keep the distinction between .reg and .reg_offset, but for
* now we don't care.
*/
unsigned int new_nr_params = 0;
for (unsigned int i = 0; i < uniforms; i++) {
if (this->params_remap[i] != -1) {
this->params_remap[i] = new_nr_params++;
}
}
/* Update the list of params to be uploaded to match our new numbering. */
for (unsigned int i = 0; i < uniforms; i++) {
int remapped = this->params_remap[i];
if (remapped == -1)
continue;
stage_prog_data->param[remapped] = stage_prog_data->param[i];
}
uniforms = new_nr_params;
} else {
/* This should have been generated in the SIMD8 pass already. */
assert(this->params_remap);
}
/* Now do the renumbering of the shader to remove unused params. */
foreach_list(node, &this->instructions) {
fs_inst *inst = (fs_inst *)node;
for (int i = 0; i < 3; i++) {
int constant_nr = inst->src[i].reg + inst->src[i].reg_offset;
if (inst->src[i].file != UNIFORM)
continue;
/* as above alias to 0 */
if (constant_nr < 0 || constant_nr >= (int)this->nr_params_remap) {
constant_nr = 0;
}
assert(this->params_remap[constant_nr] != -1);
inst->src[i].reg = this->params_remap[constant_nr];
inst->src[i].reg_offset = 0;
}
}
return true;
}
/*
* Implements array access of uniforms by inserting a
* PULL_CONSTANT_LOAD instruction.
@ -1872,8 +1793,7 @@ fs_visitor::move_uniform_array_access_to_pull_constants()
}
/**
* Choose accesses from the UNIFORM file to demote to using the pull
* constant buffer.
* Assign UNIFORM file registers to either push constants or pull constants.
*
* We allow a fragment shader to have more than the specified minimum
* maximum number of fragment shader uniform components (64). If
@ -1882,24 +1802,62 @@ fs_visitor::move_uniform_array_access_to_pull_constants()
* update the program to load them.
*/
void
fs_visitor::setup_pull_constants()
fs_visitor::assign_constant_locations()
{
/* Only allow 16 registers (128 uniform components) as push constants. */
unsigned int max_uniform_components = 16 * 8;
if (uniforms <= max_uniform_components)
/* Only the first compile (SIMD8 mode) gets to decide on locations. */
if (dispatch_width != 8)
return;
/* Just demote the end of the list. We could probably do better
/* Find which UNIFORM registers are still in use. */
bool is_live[uniforms];
for (unsigned int i = 0; i < uniforms; i++) {
is_live[i] = false;
}
foreach_list(node, &this->instructions) {
fs_inst *inst = (fs_inst *) node;
for (int i = 0; i < 3; i++) {
if (inst->src[i].file != UNIFORM)
continue;
int constant_nr = inst->src[i].reg + inst->src[i].reg_offset;
if (constant_nr >= 0 && constant_nr < (int) uniforms)
is_live[constant_nr] = true;
}
}
/* Only allow 16 registers (128 uniform components) as push constants.
*
* Just demote the end of the list. We could probably do better
* here, demoting things that are rarely used in the program first.
*/
unsigned int pull_uniform_base = max_uniform_components;
unsigned int max_push_components = 16 * 8;
unsigned int num_push_constants = 0;
push_constant_loc = ralloc_array(mem_ctx, int, uniforms);
pull_constant_loc = ralloc_array(mem_ctx, int, uniforms);
for (unsigned int i = 0; i < uniforms; i++)
pull_constant_loc[i] = -1;
for (unsigned int i = 0; i < uniforms; i++) {
if (i < pull_uniform_base) {
pull_constant_loc[i] = -1;
if (!is_live[i] || pull_constant_loc[i] != -1) {
/* This UNIFORM register is either dead, or has already been demoted
* to a pull const. Mark it as no longer living in the param[] array.
*/
push_constant_loc[i] = -1;
continue;
}
if (num_push_constants < max_push_components) {
/* Retain as a push constant. Record the location in the params[]
* array.
*/
push_constant_loc[i] = num_push_constants++;
} else {
pull_constant_loc[i] = -1;
/* Demote to a pull constant. */
push_constant_loc[i] = -1;
/* If our constant is already being uploaded for reladdr purposes,
* reuse it.
*/
@ -1916,7 +1874,22 @@ fs_visitor::setup_pull_constants()
}
}
}
uniforms = pull_uniform_base;
stage_prog_data->nr_params = num_push_constants;
/* Up until now, the param[] array has been indexed by reg + reg_offset
* of UNIFORM registers. Condense it to only contain the uniforms we
* chose to upload as push constants.
*/
for (unsigned int i = 0; i < uniforms; i++) {
int remapped = push_constant_loc[i];
if (remapped == -1)
continue;
assert(remapped <= i);
stage_prog_data->param[remapped] = stage_prog_data->param[i];
}
demote_pull_constants(false);
}
@ -3408,8 +3381,7 @@ fs_visitor::run()
split_virtual_grfs();
move_uniform_array_access_to_pull_constants();
remove_dead_constants();
setup_pull_constants();
assign_constant_locations();
opt_drop_redundant_mov_to_flags();

13
src/mesa/drivers/dri/i965/brw_fs.h
View file

@ -357,7 +357,7 @@ public:
void split_virtual_grfs();
void compact_virtual_grfs();
void move_uniform_array_access_to_pull_constants();
void setup_pull_constants();
void assign_constant_locations();
void demote_pull_constants(bool reladdr_only);
void invalidate_live_intervals();
void calculate_live_intervals();
@ -375,7 +375,6 @@ public:
bool compute_to_mrf();
bool dead_code_eliminate();
bool dead_code_eliminate_local();
bool remove_dead_constants();
bool remove_duplicate_mrf_writes();
bool virtual_grf_interferes(int a, int b);
void schedule_instructions(instruction_scheduler_mode mode);
@ -516,13 +515,11 @@ public:
*/
int *pull_constant_loc;
/* This is the map from UNIFORM hw_reg + reg_offset as generated by
* the visitor to the packed uniform number after
* remove_dead_constants() that represents the actual uploaded
* uniform index.
/**
* Array mapping UNIFORM register numbers to the push parameter index,
* or -1 if this uniform register isn't being uploaded as a push constant.
*/
int *params_remap;
int nr_params_remap;
int *push_constant_loc;
struct hash_table *variable_ht;
fs_reg frag_depth;

3
src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
View file

@ -2972,8 +2972,7 @@ fs_visitor::fs_visitor(struct brw_context *brw,
this->uniforms = 0;
this->pull_constant_loc = NULL;
this->params_remap = NULL;
this->nr_params_remap = 0;
this->push_constant_loc = NULL;
this->force_uncompressed_stack = 0;