Mesa (master): mesa/st: Don't copy propagate from swizzles.

[Ian Romanick]

Module: Mesa
Branch: master
Commit: e1ff753d67a355ad20443173b99613a1198331c1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=e1ff753d67a355ad20443173b99613a1198331c1

Author: Fabian Bieler <fabianbieler at fastmail.fm>
Date:   Sat Apr 20 19:40:11 2013 +0200

mesa/st: Don't copy propagate from swizzles.

Do not propagate a copy if source and destination are identical.

Otherwise code like

MOV TEMP[0].xyzw, TEMP[0].wzyx
MOV TEMP[1].xyzw, TEMP[0].xyzw

is changed to

MOV TEMP[0].xyzw, TEMP[0].wzyx
MOV TEMP[1].xyzw, TEMP[0].wzyx

This fixes Piglit test shaders/glsl-copy-propagation-self-2 for gallium drivers.

NOTE: This is a candidate for the stable branches.
Signed-off-by: Fabian Bieler <fabianbieler at fastmail.fm>
Reviewed-by: Brian Paul <brianp at vmware.com>

---

 src/mesa/state_tracker/st_glsl_to_tgsi.cpp |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index ed314a0..5f1ffec 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -3552,6 +3552,8 @@ glsl_to_tgsi_visitor::copy_propagate(void)
       /* If this is a copy, add it to the ACP. */
       if (inst->op == TGSI_OPCODE_MOV &&
           inst->dst.file == PROGRAM_TEMPORARY &&
+          !(inst->dst.file == inst->src[0].file &&
+             inst->dst.index == inst->src[0].index) &&
           !inst->dst.reladdr &&
           !inst->saturate &&
           !inst->src[0].reladdr &&