Mesa (master): i965/fp: Emit discard jumps.

[Kenneth Graunke]

Module: Mesa
Branch: master
Commit: 201aef9d1370ff524f856b725d2328c4f48199e8
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=201aef9d1370ff524f856b725d2328c4f48199e8

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Tue Feb 24 12:48:56 2015 -0800

i965/fp: Emit discard jumps.

This should improve the performance of any shaders using the KIL
instruction.  I'm a bit surprised we missed this.

Unfortunately, I have not been able to measure any performance
improvements from this patch.  It does make ARB_fragment_program
behave similarly to GLSL code.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Matt Turner <mattst88 at gmail.com>

---

 src/mesa/drivers/dri/i965/brw_fs_fp.cpp |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_fp.cpp b/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
index 6d08bf7..c4064da 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
@@ -250,6 +250,9 @@ fs_visitor::emit_fragment_program_code()
                                     fs_reg(0.0f), BRW_CONDITIONAL_GE));
             cmp->predicate = BRW_PREDICATE_NORMAL;
             cmp->flag_subreg = 1;
+
+            if (brw->gen >= 6)
+               emit_discard_jump();
          }
          break;
       }