From a39167d5949c76dfb48994caead4b59ab5f80318 Mon Sep 17 00:00:00 2001 From: Thomas Helland Date: Thu, 6 Aug 2015 13:36:04 +0200 Subject: [PATCH] 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 Reviewed-by: Matt Turner --- src/glsl/nir/nir_opt_algebraic.py | 1 + 1 file changed, 1 insertion(+) 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))), -- 2.30.2