[Mesa-dev] [PATCH 5/5] i965/fs: Fix test for smearing enabled on an instruction.

[Eric Anholt]

We were expanding the live range too far, breaking register_coalesce_2()
and compute_to_mrf() on 16-wide shaders.  Turning it back on improves
GLB2.7 performance by 0.239355% +/- 0.0850649% (n=398), though some
16-wide shaders are lost.  shader-db stats are:

total instructions in shared programs: 1627211 -> 1609262 (-1.10%)
instructions in affected programs:     450351 -> 432402 (-3.99%)

While 33 new 16-wide shaders are gained, 70 are lost.
---
 src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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 3daf8fa..f5daab2 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
@@ -216,7 +216,7 @@ fs_visitor::calculate_live_intervals()
              * pixel_x/pixel_y, which are registers of 16-bit values and thus
              * would get stomped by the first decode as well.
              */
-            if (dispatch_width == 16 && (inst->src[i].smear ||
+            if (dispatch_width == 16 && (inst->src[i].smear >= 0 ||
                                          (this->pixel_x.reg == reg ||
                                           this->pixel_y.reg == reg))) {
                end_ip++;
-- 
1.8.3.rc0