[Mesa-dev] [PATCH 1/4] i965: Don't emit saturates for instructions without destinations.

[Matt Turner]

We were special casing OPCODE_END but no other instructions that have no
destination, like OPCODE_KIL, leading us to emitting MOVs with null
destinations.

total instructions in shared programs: 5950886 -> 5947182 (-0.06%)
instructions in affected programs:     139700 -> 135996 (-2.65%)
helped:                                904
---
 src/mesa/drivers/dri/i965/brw_fs_fp.cpp   | 2 +-
 src/mesa/drivers/dri/i965/brw_vec4_vp.cpp | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_fp.cpp b/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
index 7f2874d..dd3d331 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_fp.cpp
@@ -517,7 +517,7 @@ fs_visitor::emit_fragment_program_code()
       /* To handle saturates, we emit a MOV with a saturate bit, which
        * optimization should fold into the preceding instructions when safe.
        */
-      if (fpi->Opcode != OPCODE_END) {
+      if (_mesa_num_inst_dst_regs(fpi->Opcode) != 0) {
          fs_reg real_dst = get_fp_dst_reg(&fpi->DstReg);
 
          for (int i = 0; i < 4; i++) {
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_vp.cpp b/src/mesa/drivers/dri/i965/brw_vec4_vp.cpp
index 85f2de5..434f032 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_vp.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_vp.cpp
@@ -387,7 +387,7 @@ vec4_vs_visitor::emit_program_code()
       }
 
       /* Copy the temporary back into the actual destination register. */
-      if (vpi->Opcode != OPCODE_END) {
+      if (_mesa_num_inst_dst_regs(vpi->Opcode) != 0) {
          emit(MOV(get_vp_dst_reg(vpi->DstReg), src_reg(dst)));
       }
    }
-- 
2.0.5