[Mesa-dev] [PATCH 2/3] i965/vs: Allow copy propagation into MUL/MACH.

[Eric Anholt]

This is a trivial port of 1d6ead38042cc0d1e667d8ff55937c1e32d108b1 from
the FS.

No significant performance difference on trex (misplaced the data, but it
was about n=20).
---
 src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
index 1a667eb..64f6ccc 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
@@ -95,6 +95,7 @@ try_constant_propagation(vec4_instruction *inst, int arg, src_reg *values[4])
       inst->src[arg] = value;
       return true;
 
+   case BRW_OPCODE_MACH:
    case BRW_OPCODE_MUL:
    case BRW_OPCODE_ADD:
       if (arg == 1) {
@@ -102,9 +103,10 @@ try_constant_propagation(vec4_instruction *inst, int arg, src_reg *values[4])
 	 return true;
       } else if (arg == 0 && inst->src[1].file != IMM) {
 	 /* Fit this constant in by commuting the operands.  Exception: we
-	  * can't do this for 32-bit integer MUL because it's asymmetric.
+	  * can't do this for 32-bit integer MUL/MACH because it's asymmetric.
 	  */
-	 if (inst->opcode == BRW_OPCODE_MUL &&
+	 if ((inst->opcode == BRW_OPCODE_MUL ||
+              inst->opcode == BRW_OPCODE_MACH) &&
 	     (inst->src[1].type == BRW_REGISTER_TYPE_D ||
 	      inst->src[1].type == BRW_REGISTER_TYPE_UD))
 	    break;
-- 
1.8.3.rc0