On 02/19/2013 06:03 PM, Eric Anholt wrote:
We can execute way fewer instructions by doing our boolean manipulation
on an "int" of bits at a time, while also reducing our working set size.
I see...it lets you do the computation on whole words at a time rather
than looping over (up to) 32 individual bools. Yeah. That would be
much faster.
Reduces compile time of L4D2's slowest shader from 4s to 1.1s
(-72.4% +/- 0.2%, n=10)
---
.../drivers/dri/i965/brw_fs_live_variables.cpp | 44 +++++++++++---------
src/mesa/drivers/dri/i965/brw_fs_live_variables.h | 10 +++--
2 files changed, 30 insertions(+), 24 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
b/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
index db8f397..e7de43e 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
@@ -40,7 +40,7 @@ using namespace brw;
*/
/**
- * Sets up the use[] and def[] arrays.
+ * Sets up the use[] and def[] bitsets.
*
* The basic-block-level live variable analysis needs to know which
* variables get used before they're completely defined, and which
@@ -67,8 +67,8 @@ fs_live_variables::setup_def_use()
if (inst->src[i].file == GRF) {
int reg = inst->src[i].reg;
- if (!bd[b].def[reg])
- bd[b].use[reg] = true;
+ if (!BITSET_TEST(bd[b].def, reg))
+ BITSET_SET(bd[b].use, reg);
}
}
@@ -82,8 +82,8 @@ fs_live_variables::setup_def_use()
!inst->force_uncompressed &&
!inst->force_sechalf) {
int reg = inst->dst.reg;
- if (!bd[b].use[reg])
- bd[b].def[reg] = true;
+ if (!BITSET_TEST(bd[b].use, reg))
+ BITSET_SET(bd[b].def, reg);
}
ip++;
@@ -107,12 +107,12 @@ fs_live_variables::compute_live_variables()
for (int b = 0; b < cfg->num_blocks; b++) {
/* Update livein */
- for (int i = 0; i < num_vars; i++) {
- if (bd[b].use[i] || (bd[b].liveout[i] && !bd[b].def[i])) {
- if (!bd[b].livein[i]) {
- bd[b].livein[i] = true;
- cont = true;
- }
+ for (int i = 0; i < bitset_words; i++) {
+ BITSET_WORD new_livein = (bd[b].use[i] |
+ (bd[b].liveout[i] & ~bd[b].def[i]));
+ if (new_livein & ~bd[b].livein[i]) {
+ bd[b].livein[i] |= new_livein;
+ cont = true;
}
}
@@ -121,9 +121,11 @@ fs_live_variables::compute_live_variables()
bblock_link *link = (bblock_link *)block_node;
bblock_t *block = link->block;
- for (int i = 0; i < num_vars; i++) {
- if (bd[block->block_num].livein[i] && !bd[b].liveout[i]) {
- bd[b].liveout[i] = true;
+ for (int i = 0; i < bitset_words; i++) {
+ BITSET_WORD new_liveout = (bd[block->block_num].livein[i] &
+ ~bd[b].liveout[i]);
+ if (new_liveout & ~bd[b].liveout[i]) {
+ bd[b].liveout[i] |= new_liveout;
This hunk doesn't quite seem right...new_liveout already has &
~bd[b].liveout[i]...so couldn't the if condition just be new_liveout? It
seems equivalent.
Otherwise, this patch looks good and gets a:
Reviewed-by: Kenneth Graunke <kenn...@whitecape.org>
cont = true;
}
}
@@ -140,11 +142,13 @@ fs_live_variables::fs_live_variables(fs_visitor *v, cfg_t
*cfg)
num_vars = v->virtual_grf_count;
bd = rzalloc_array(mem_ctx, struct block_data, cfg->num_blocks);
+ bitset_words = (ALIGN(v->virtual_grf_count, BITSET_WORDBITS) /
+ BITSET_WORDBITS);
for (int i = 0; i < cfg->num_blocks; i++) {
- bd[i].def = rzalloc_array(mem_ctx, bool, num_vars);
- bd[i].use = rzalloc_array(mem_ctx, bool, num_vars);
- bd[i].livein = rzalloc_array(mem_ctx, bool, num_vars);
- bd[i].liveout = rzalloc_array(mem_ctx, bool, num_vars);
+ bd[i].def = rzalloc_array(mem_ctx, BITSET_WORD, bitset_words);
+ bd[i].use = rzalloc_array(mem_ctx, BITSET_WORD, bitset_words);
+ bd[i].livein = rzalloc_array(mem_ctx, BITSET_WORD, bitset_words);
+ bd[i].liveout = rzalloc_array(mem_ctx, BITSET_WORD, bitset_words);
}
setup_def_use();
@@ -208,12 +212,12 @@ fs_visitor::calculate_live_intervals()
for (int b = 0; b < cfg.num_blocks; b++) {
for (int i = 0; i < num_vars; i++) {
- if (livevars.bd[b].livein[i]) {
+ if (BITSET_TEST(livevars.bd[b].livein, i)) {
def[i] = MIN2(def[i], cfg.blocks[b]->start_ip);
use[i] = MAX2(use[i], cfg.blocks[b]->start_ip);
}
- if (livevars.bd[b].liveout[i]) {
+ if (BITSET_TEST(livevars.bd[b].liveout, i)) {
def[i] = MIN2(def[i], cfg.blocks[b]->end_ip);
use[i] = MAX2(use[i], cfg.blocks[b]->end_ip);
}
diff --git a/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
b/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
index 5f7e67e..1cde5f4 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
+++ b/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
@@ -26,6 +26,7 @@
*/
#include "brw_fs.h"
+#include "main/bitset.h"
namespace brw {
@@ -36,18 +37,18 @@ struct block_data {
* Note that for our purposes, "defined" means unconditionally, completely
* defined.
*/
- bool *def;
+ BITSET_WORD *def;
/**
* Which variables are used before being defined in the block.
*/
- bool *use;
+ BITSET_WORD *use;
/** Which defs reach the entry point of the block. */
- bool *livein;
+ BITSET_WORD *livein;
/** Which defs reach the exit point of the block. */
- bool *liveout;
+ BITSET_WORD *liveout;
};
class fs_live_variables {
@@ -73,6 +74,7 @@ public:
void *mem_ctx;
int num_vars;
+ int bitset_words;
/** Per-basic-block information on live variables */
struct block_data *bd;
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