i965: Avoid dependency hints on math opcodes

  Putting NoDDClr and NoDDChk dependency control on instruction
sequences that include math opcodes can cause corruption of channels.
Treat math opcodes like send opcodes and suppress dependency hinting.

Signed-off-by: Mike Stroyan <mike@LunarG.com>
Tested-by: Tony Bertapelli <anthony.p.bertapelli@intel.com>
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Matt Turner <mattst88@gmail.com>

diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index c34eec4d7dc71f6245641961d1dccf46fca69f63..480a3097b428608800cb732e587987c202252bf5 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -849,6 +849,14 @@ vec4_visitor::opt_set_dependency_control()
             continue;
          }
 
+         /* Dependency control does not work well over math instructions.
+          */
+         if (inst->is_math()) {
+            memset(last_grf_write, 0, sizeof(last_grf_write));
+            memset(last_mrf_write, 0, sizeof(last_mrf_write));
+            continue;
+         }
+
          /* Now, see if we can do dependency control for this instruction
           * against a previous one writing to its destination.
           */