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authorThomas Helland <[email protected]>2015-08-06 13:36:04 +0200
committerMatt Turner <[email protected]>2015-08-18 11:34:44 -0700
commita39167d5949c76dfb48994caead4b59ab5f80318 (patch)
tree4315cc93fbb82078da4295dd299643aff2e5bab1 /src/glsl/nir
parent29264d0d0cd5ca24314630d9dc22b3f971344a34 (diff)
nir: Simplify fne(fneg(a), a) -> fne(a, 0.0)
-NaN != NaN, and -Inf != Inf, so this should be safe. Found while working on my VRP pass. Shader-db results on my IVB: total instructions in shared programs: 1698267 -> 1698067 (-0.01%) instructions in affected programs: 15785 -> 15585 (-1.27%) helped: 36 HURT: 0 GAINED: 0 LOST: 0 Some shaders was found to have the following pattern in NIR: vec1 ssa_26 = fneg ssa_21 vec1 ssa_27 = fne ssa_21, ssa_26 Make that: vec1 ssa_27 = fne ssa_21, 0.0f This is found in Dota2 and Brutal Legend. One shader is cut by 8%, from 323 -> 296 instructons in SIMD8 Signed-off-by: Thomas Helland <[email protected]> Reviewed-by: Matt Turner <[email protected]>
Diffstat (limited to 'src/glsl/nir')
-rw-r--r--src/glsl/nir/nir_opt_algebraic.py1
1 files changed, 1 insertions, 0 deletions
diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
index d7c17403f9f..b76fef236a9 100644
--- a/src/glsl/nir/nir_opt_algebraic.py
+++ b/src/glsl/nir/nir_opt_algebraic.py
@@ -113,6 +113,7 @@ optimizations = [
(('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
(('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
(('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
+ (('fne', ('fneg', a), a), ('fne', a, 0.0)),
# Emulating booleans
(('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
(('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),