Mesa (master): i965/fs: Add algebraic optimizations for MAD.

[Matt Turner]

Module: Mesa
Branch: master
Commit: bb33a31c3830945ae768ebdaeb686291bdf897fa
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=bb33a31c3830945ae768ebdaeb686291bdf897fa

Author: Matt Turner <mattst88 at gmail.com>
Date:   Sun Nov  9 17:27:52 2014 -0800

i965/fs: Add algebraic optimizations for MAD.

total instructions in shared programs: 5764176 -> 5763808 (-0.01%)
instructions in affected programs:     25121 -> 24753 (-1.46%)
helped:                                164
HURT:                                  2

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/mesa/drivers/dri/i965/brw_fs.cpp |   43 ++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 22cd77d..c46e1d7 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2343,6 +2343,14 @@ fs_visitor::opt_algebraic()
             break;
          }
 
+         if (inst->src[0].file == IMM) {
+            assert(inst->src[0].type == BRW_REGISTER_TYPE_F);
+            inst->opcode = BRW_OPCODE_MOV;
+            inst->src[0].fixed_hw_reg.dw1.f *= inst->src[1].fixed_hw_reg.dw1.f;
+            inst->src[1] = reg_undef;
+            progress = true;
+            break;
+         }
 	 break;
       case BRW_OPCODE_ADD:
          if (inst->src[1].file != IMM)
@@ -2355,6 +2363,15 @@ fs_visitor::opt_algebraic()
             progress = true;
             break;
          }
+
+         if (inst->src[0].file == IMM) {
+            assert(inst->src[0].type == BRW_REGISTER_TYPE_F);
+            inst->opcode = BRW_OPCODE_MOV;
+            inst->src[0].fixed_hw_reg.dw1.f += inst->src[1].fixed_hw_reg.dw1.f;
+            inst->src[1] = reg_undef;
+            progress = true;
+            break;
+         }
          break;
       case BRW_OPCODE_OR:
          if (inst->src[0].equals(inst->src[1])) {
@@ -2429,6 +2446,32 @@ fs_visitor::opt_algebraic()
             }
          }
          break;
+      case BRW_OPCODE_MAD:
+         if (inst->src[1].is_zero() || inst->src[2].is_zero()) {
+            inst->opcode = BRW_OPCODE_MOV;
+            inst->src[1] = reg_undef;
+            inst->src[2] = reg_undef;
+            progress = true;
+         } else if (inst->src[0].is_zero()) {
+            inst->opcode = BRW_OPCODE_MUL;
+            inst->src[0] = inst->src[2];
+            inst->src[2] = reg_undef;
+         } else if (inst->src[1].is_one()) {
+            inst->opcode = BRW_OPCODE_ADD;
+            inst->src[1] = inst->src[2];
+            inst->src[2] = reg_undef;
+            progress = true;
+         } else if (inst->src[2].is_one()) {
+            inst->opcode = BRW_OPCODE_ADD;
+            inst->src[2] = reg_undef;
+            progress = true;
+         } else if (inst->src[1].file == IMM && inst->src[2].file == IMM) {
+            inst->opcode = BRW_OPCODE_ADD;
+            inst->src[1].fixed_hw_reg.dw1.f *= inst->src[2].fixed_hw_reg.dw1.f;
+            inst->src[2] = reg_undef;
+            progress = true;
+         }
+         break;
       case SHADER_OPCODE_RCP: {
          fs_inst *prev = (fs_inst *)inst->prev;
          if (prev->opcode == SHADER_OPCODE_SQRT) {