From a4079f1cb2d7142d798f6d7fcb7ef29f34976f5b Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Mon, 7 Mar 2016 13:09:30 -0800 Subject: [PATCH] nir: Lower flrp with Boolean interpolator to bcsel On Intel platforms that don't set lower_flrp, using bcsel instead of flrp seems to be a small amount worse. On those platforms, the use of flrp, bcsel, and multiply of b2f is still an active area of research. In review, Matt suggested this is because bcsel turns into CMP+SEL, and because of the flag register we can't schedule instructions well. shader-db results: G4X / Ironlake total instructions in shared programs: 4016538 -> 4012279 (-0.11%) instructions in affected programs: 161556 -> 157297 (-2.64%) helped: 1077 HURT: 1 total cycles in shared programs: 84328296 -> 84315862 (-0.01%) cycles in affected programs: 4174570 -> 4162136 (-0.30%) helped: 926 HURT: 53 Unsurprisingly, no changes on later platforms. Signed-off-by: Ian Romanick Reviewed-by: Matt Turner --- src/compiler/nir/nir_opt_algebraic.py | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index 39be85f639e..8a44a7a0a66 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -83,10 +83,13 @@ optimizations = [ (('flrp', a, b, 1.0), b), (('flrp', a, a, b), a), (('flrp', 0.0, a, b), ('fmul', a, b)), + (('flrp', a, b, ('b2f', c)), ('bcsel', c, b, a), 'options->lower_flrp'), (('flrp', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp'), (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'), - (('fadd', ('fmul', a, ('fadd', 1.0, ('fneg', c))), ('fmul', b, c)), ('flrp', a, b, c), '!options->lower_flrp'), - (('fadd', a, ('fmul', c, ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp'), + (('fadd', ('fmul', a, ('fadd', 1.0, ('fneg', ('b2f', c)))), ('fmul', b, ('b2f', c))), ('bcsel', c, b, a), 'options->lower_flrp'), + (('fadd', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp'), + (('fadd', a, ('fmul', ('b2f', c), ('fadd', b, ('fneg', a)))), ('bcsel', c, b, a), 'options->lower_flrp'), + (('fadd', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp'), (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options->lower_ffma'), (('fadd', ('fmul', a, b), c), ('ffma', a, b, c), '!options->lower_ffma'), # Comparison simplifications -- 2.30.2