Mesa (master): i965/fs: Drop our dead push constants before overflowing to pull constants.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 774b787d6b7abe601309cf437b09b592fea0394d
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=774b787d6b7abe601309cf437b09b592fea0394d

Author: Eric Anholt <eric at anholt.net>
Date:   Mon Oct 28 17:00:23 2013 -0700

i965/fs: Drop our dead push constants before overflowing to pull constants.

The idea of the original order was that you'd dead code eliminate accesses
to push constants.  But I've never seen a case of that (nor has
shader-db), while we frequently see sparse accesses of large constant
arrays that would overflow into pull constants.

Cuts pull constant use on csgo, serious sam, planeshift, and the cave:

total instructions in shared programs: 1695103 -> 1688795 (-0.37%)
instructions in affected programs:     92024 -> 85716 (-6.85%)
GAINED:                                339
LOST:                                  0

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/mesa/drivers/dri/i965/brw_fs.cpp |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 76d8a29..a60941a 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3070,6 +3070,7 @@ fs_visitor::run()
       split_virtual_grfs();
 
       move_uniform_array_access_to_pull_constants();
+      remove_dead_constants();
       setup_pull_constants();
 
       bool progress;
@@ -3090,8 +3091,6 @@ fs_visitor::run()
 	 progress = compute_to_mrf() || progress;
       } while (progress);
 
-      remove_dead_constants();
-
       schedule_instructions(false);
 
       lower_uniform_pull_constant_loads();