Mesa (master): i965: Fix accumulator_contains() test to also reject swizzles of the dst.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 6754ec831e5aaec516db929c8db6e7478a2f5540
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=6754ec831e5aaec516db929c8db6e7478a2f5540

Author: Eric Anholt <eric at anholt.net>
Date:   Sun Aug 12 23:30:18 2012 -0700

i965: Fix accumulator_contains() test to also reject swizzles of the dst.

When faced with this sequence:

	MOV	R1, c[1];
	MAD	R0, R2, R1.x, R1.y;

we were concluding that the MOV of R1 set up our accumulator and so we could
just use the previous result.  Only, it's got R1.xyzw in it instead of the
r1.y we're looking for.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=46784
NOTE: This is a candidate for the 8.0 branch.

---

 src/mesa/drivers/dri/i965/brw_vs_emit.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_vs_emit.c b/src/mesa/drivers/dri/i965/brw_vs_emit.c
index 6169f73..177b2b3 100644
--- a/src/mesa/drivers/dri/i965/brw_vs_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_vs_emit.c
@@ -1743,7 +1743,7 @@ accumulator_contains(struct brw_vs_compile *c, struct brw_reg val)
    if (val.address_mode != BRW_ADDRESS_DIRECT)
       return false;
 
-   if (val.negate || val.abs)
+   if (val.negate || val.abs || val.dw1.bits.swizzle != BRW_SWIZZLE_XYZW)
       return false;
 
    switch (prev_insn->header.opcode) {