This is the "COPY" set from Muchnick's textbook, which is necessary
to do the dataflow algorithm correctly.
Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
---
.../drivers/dri/i965/brw_fs_copy_propagation.cpp | 27 ++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
index 7aff36b..2970af6 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
@@ -64,6 +64,13 @@ struct block_data {
BITSET_WORD *liveout;
/**
+ * Which entries in the fs_copy_prop_dataflow acp table are generated by
+ * instructions in this block which reach the end of the block without
+ * being killed.
+ */
+ BITSET_WORD *copy;
+
+ /**
* Which entries in the fs_copy_prop_dataflow acp table are killed over the
* course of this block.
*/
@@ -113,6 +120,7 @@ fs_copy_prop_dataflow::fs_copy_prop_dataflow(void *mem_ctx,
cfg_t *cfg,
for (int b = 0; b < cfg->num_blocks; b++) {
bd[b].livein = rzalloc_array(bd, BITSET_WORD, bitset_words);
bd[b].liveout = rzalloc_array(bd, BITSET_WORD, bitset_words);
+ bd[b].copy = rzalloc_array(bd, BITSET_WORD, bitset_words);
bd[b].kill = rzalloc_array(bd, BITSET_WORD, bitset_words);
for (int i = 0; i < ACP_HASH_SIZE; i++) {
@@ -148,15 +156,26 @@ fs_copy_prop_dataflow::setup_initial_values()
if (inst->dst.file != GRF)
continue;
- /* Mark ACP entries which are killed by this instruction. */
for (int i = 0; i < num_acp; i++) {
- if (inst != acp[i]->inst &&
- (inst->overwrites_reg(acp[i]->dst) ||
- inst->overwrites_reg(acp[i]->src))) {
+ if (inst == acp[i]->inst) {
+ /* Add this entry to the COPY set. */
+ BITSET_SET(bd[b].copy, i);
+ } else if (inst->overwrites_reg(acp[i]->dst) ||
+ inst->overwrites_reg(acp[i]->src)) {
+ /* The current instruction kills this copy. Add the entry to
+ * the KILL set.
+ */
BITSET_SET(bd[b].kill, i);
}
}
}
+
+ /* Anything killed did not make it to the end of the block, so it
+ * shouldn't be in COPY.
+ */
+ for (int i = 0; i < bitset_words; i++) {
+ bd[b].copy[i] &= ~bd[b].kill[i];
+ }
}
}
--
1.8.3.4
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