Previously, livein was initialized to 0 for all blocks. According to
the textbook, it should be the universal set (~0) for all blocks except
the one representing the start of the program (which should be 0).
liveout also needs to be initialized to COPY for the initial block.
Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
---
.../drivers/dri/i965/brw_fs_copy_propagation.cpp | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
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 fd726e0..3344f89 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
@@ -147,6 +147,7 @@ fs_copy_prop_dataflow::fs_copy_prop_dataflow(void *mem_ctx,
cfg_t *cfg,
void
fs_copy_prop_dataflow::setup_initial_values()
{
+ /* Initialize the COPY and KILL sets. */
for (int b = 0; b < cfg->num_blocks; b++) {
bblock_t *block = cfg->blocks[b];
@@ -177,6 +178,26 @@ fs_copy_prop_dataflow::setup_initial_values()
bd[b].copy[i] &= ~bd[b].kill[i];
}
}
+
+ /* Populate the initial values for the livein and liveout sets. For the
+ * block at the start of the program, livein = 0 and liveout = copy.
+ * For the others, set liveout to 0 (the empty set) and livein to ~0
+ * (the universal set).
+ */
+ for (int b = 0; b < cfg->num_blocks; b++) {
+ bblock_t *block = cfg->blocks[b];
+ if (block->parents.is_empty()) {
+ for (int i = 0; i < bitset_words; i++) {
+ bd[b].livein[i] = 0u;
+ bd[b].liveout[i] = bd[b].copy[i];
+ }
+ } else {
+ for (int i = 0; i < bitset_words; i++) {
+ bd[b].liveout[i] = 0u;
+ bd[b].livein[i] = ~0u;
+ }
+ }
+ }
}
/**
--
1.8.3.4
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