[Mesa-dev] [PATCH] i965/fs: Optimize LRP with x == y into a MOV.

[Matt Turner]

total instructions in shared programs: 1487331 -> 1485988 (-0.09%)
instructions in affected programs:     45638 -> 44295 (-2.94%)
GAINED:                                7
LOST:                                  0
---
No change from the equivalent vec4 change.

 src/mesa/drivers/dri/i965/brw_fs.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index ee1b0c2..c2955d6 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2000,6 +2000,16 @@ fs_visitor::opt_algebraic()
             break;
          }
          break;
+      case BRW_OPCODE_LRP:
+         if (inst->src[1].equals(inst->src[2])) {
+            inst->opcode = BRW_OPCODE_MOV;
+            inst->src[0] = inst->src[1];
+            inst->src[1] = reg_undef;
+            inst->src[2] = reg_undef;
+            progress = true;
+            break;
+         }
+         break;
       case BRW_OPCODE_SEL:
          if (inst->saturate && inst->src[1].file == IMM) {
             switch (inst->conditional_mod) {
-- 
1.8.3.2