[Mesa-dev] [PATCH 10/16] i965/fs: Eliminate null-dst instructions without side-effects.

[Matt Turner]

---
 src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp 
b/src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp
index 81be4de..d66808b 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp
@@ -85,6 +85,17 @@ fs_visitor::dead_code_eliminate()
             }
          }
 
+         if ((inst->opcode != BRW_OPCODE_IF &&
+              inst->opcode != BRW_OPCODE_WHILE) &&
+             inst->dst.is_null() &&
+             !inst->has_side_effects() &&
+             !inst->writes_flag() &&
+             !inst->writes_accumulator) {
+            inst->opcode = BRW_OPCODE_NOP;
+            progress = true;
+            continue;
+         }
+
          if (inst->dst.file == GRF) {
             if (!inst->is_partial_write()) {
                int var = live_intervals->var_from_reg(inst->dst);
-- 
2.0.4

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