Mesa (master): i965/fs: Allow constant propagation into MACH.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 1d6ead38042cc0d1e667d8ff55937c1e32d108b1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=1d6ead38042cc0d1e667d8ff55937c1e32d108b1

Author: Eric Anholt <eric at anholt.net>
Date:   Fri Mar 15 14:21:30 2013 -0700

i965/fs: Allow constant propagation into MACH.

This happens quite a bit with varying-index uniform loads.  We could also
do better by avoiding the MACH entirely, but there's no reason not to at
least take this step.

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

---

 .../drivers/dri/i965/brw_fs_copy_propagation.cpp   |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
index ec72ede..96c9b4e 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
@@ -262,6 +262,7 @@ fs_visitor::try_constant_propagate(fs_inst *inst, acp_entry *entry)
          progress = true;
          break;
 
+      case BRW_OPCODE_MACH:
       case BRW_OPCODE_MUL:
       case BRW_OPCODE_ADD:
          if (i == 1) {
@@ -269,10 +270,11 @@ fs_visitor::try_constant_propagate(fs_inst *inst, acp_entry *entry)
             progress = true;
          } else if (i == 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
+             * Exception: we 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;