i965/vs: Allow copy propagation into MUL/MACH.

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).

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>

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 (file)
--- 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;