Comment # 3
on bug 89944
from Sami Liedes
I bisected this down to this commit:
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commit 30f51f1a1a70bc838d5bed449daff0dd9f2e8ef2
Author: Kenneth Graunke <kenneth@whitecape.org>
Date: Wed Oct 22 20:48:21 2014 -0700
glsl: Optimize "if (cond) discard;" to a conditional discard.
st_glsl_to_tgsi and ir_to_mesa have handled conditional discards for a
long time; the previous patch added that capability to i965.
i965 (Haswell) shader-db stats:
Without NIR:
total instructions in shared programs: 5792133 -> 5776360 (-0.27%)
instructions in affected programs: 737585 -> 721812 (-2.14%)
helped: 6300
HURT: 68
GAINED: 2
With NIR:
total instructions in shared programs: 5787538 -> 5769569 (-0.31%)
instructions in affected programs: 767843 -> 749874 (-2.34%)
helped: 6522
HURT: 35
GAINED: 6
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
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I can also confirm that reverting that commit on top of recent HEAD (4deca127)
fixes the issue.
I can attach R600_DEBUG=ps,gs,vs output from the offending commit and its
parent if you think comparing them is of any use.