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authorEric Anholt <[email protected]>2015-03-29 23:04:21 -0700
committerEric Anholt <[email protected]>2015-04-01 10:57:01 -0700
commit15b03b7964fc2c3c52e9f384815b76957f557878 (patch)
tree1d00b9d4b20bc34ebe6d155c14e823f6a00eea23 /src/glsl
parent6e8d4a2f8043a3a7a28175326e63770aa9511ee7 (diff)
nir: Recognize a pattern of bool frobbing from TGSI KILL_IF.
TGSI's conditional discards take float arg and negate it, so GLSL to TGSI generates a b2f and negates that value. Only, in NIR we want a proper bool once again, so we compare with 0. This is a lot of pointless extra instructions. total instructions in shared programs: 39735 -> 39702 (-0.08%) instructions in affected programs: 1342 -> 1309 (-2.46%) Reviewed-by: Connor Abbott <[email protected]>
Diffstat (limited to 'src/glsl')
-rw-r--r--src/glsl/nir/nir_opt_algebraic.py2
1 files changed, 2 insertions, 0 deletions
diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
index 301d7a8ebcf..190bd916efe 100644
--- a/src/glsl/nir/nir_opt_algebraic.py
+++ b/src/glsl/nir/nir_opt_algebraic.py
@@ -100,6 +100,8 @@ optimizations = [
(('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
(('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
(('iand', 'a@bool', 1.0), ('b2f', a)),
+ (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
+ (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
# Comparison with the same args. Note that these are not done for
# the float versions because NaN always returns false on float
# inequalities.