i965/fs: Fully recompute liveout at each step.

Since we start with an overestimation of livein (0xffffffff), successive
steps can actually take away values.  This means we can't simply OR in
new liveout values; we need to recompute it from scratch at each
iteration of the fixed-point algorithm.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Paul Berry <stereotype441@gmail.com>

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 7662f6a3656f6f2ab1f212214ffd1f0a09d6d2ff..90a3f4fbc0c0678959623667f01a6b25fa400ee7 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
@@ -211,7 +211,7 @@ fs_copy_prop_dataflow::run()
          for (int i = 0; i < bitset_words; i++) {
             const BITSET_WORD old_liveout = bd[b].liveout[i];
 
-            bd[b].liveout[i] |=
+            bd[b].liveout[i] =
                bd[b].copy[i] | (bd[b].livein[i] & ~bd[b].kill[i]);
 
             if (old_liveout != bd[b].liveout[i])