src/glsl/nir/nir_opt_algebraic.py

   1 #! /usr/bin/env python
   2 #
   3 # Copyright (C) 2014 Intel Corporation
   4 #
   5 # Permission is hereby granted, free of charge, to any person obtaining a
   6 # copy of this software and associated documentation files (the "Software"),
   7 # to deal in the Software without restriction, including without limitation
   8 # the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9 # and/or sell copies of the Software, and to permit persons to whom the
  10 # Software is furnished to do so, subject to the following conditions:
  11 #
  12 # The above copyright notice and this permission notice (including the next
  13 # paragraph) shall be included in all copies or substantial portions of the
  14 # Software.
  15 #
  16 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19 # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22 # IN THE SOFTWARE.
  23 #
  24 # Authors:
  25 #    Jason Ekstrand (jason@jlekstrand.net)
  26
  27 import nir_algebraic
  28
  29 # Convenience variables
  30 a = 'a'
  31 b = 'b'
  32 c = 'c'
  33 d = 'd'
  34
  35 # Written in the form (<search>, <replace>) where <search> is an expression
  36 # and <replace> is either an expression or a value.  An expression is
  37 # defined as a tuple of the form (<op>, <src0>, <src1>, <src2>, <src3>)
  38 # where each source is either an expression or a value.  A value can be
  39 # either a numeric constant or a string representing a variable name.
  40 #
  41 # Variable names are specified as "[#]name[@type]" where "#" inicates that
  42 # the given variable will only match constants and the type indicates that
  43 # the given variable will only match values from ALU instructions with the
  44 # given output type.
  45 #
  46 # For constants, you have to be careful to make sure that it is the right
  47 # type because python is unaware of the source and destination types of the
  48 # opcodes.
  49
  50 optimizations = [
  51    (('fneg', ('fneg', a)), a),
  52    (('ineg', ('ineg', a)), a),
  53    (('fabs', ('fabs', a)), ('fabs', a)),
  54    (('fabs', ('fneg', a)), ('fabs', a)),
  55    (('iabs', ('iabs', a)), ('iabs', a)),
  56    (('iabs', ('ineg', a)), ('iabs', a)),
  57    (('fadd', a, 0.0), a),
  58    (('iadd', a, 0), a),
  59    (('fmul', a, 0.0), 0.0),
  60    (('imul', a, 0), 0),
  61    (('fmul', a, 1.0), a),
  62    (('imul', a, 1), a),
  63    (('fmul', a, -1.0), ('fneg', a)),
  64    (('imul', a, -1), ('ineg', a)),
  65    (('ffma', 0.0, a, b), b),
  66    (('ffma', a, 0.0, b), b),
  67    (('ffma', a, b, 0.0), ('fmul', a, b)),
  68    (('ffma', a, 1.0, b), ('fadd', a, b)),
  69    (('ffma', 1.0, a, b), ('fadd', a, b)),
  70    (('flrp', a, b, 0.0), a),
  71    (('flrp', a, b, 1.0), b),
  72    (('flrp', a, a, b), a),
  73    (('flrp', 0.0, a, b), ('fmul', a, b)),
  74    (('fadd', ('fmul', a, b), c), ('ffma', a, b, c)),
  75    # Comparison simplifications
  76    (('inot', ('flt', a, b)), ('fge', a, b)),
  77    (('inot', ('fge', a, b)), ('flt', a, b)),
  78    (('inot', ('ilt', a, b)), ('ige', a, b)),
  79    (('inot', ('ige', a, b)), ('ilt', a, b)),
  80    (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
  81    (('fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
  82    (('feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
  83    (('fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
  84    (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
  85    (('fmin', ('fmax', a, 1.0), 0.0), ('fsat', a)),
  86    # Logical and bit operations
  87    (('fand', a, 0.0), 0.0),
  88    (('iand', a, a), a),
  89    (('iand', a, 0), 0),
  90    (('ior', a, a), a),
  91    (('ior', a, 0), a),
  92    (('fxor', a, a), 0.0),
  93    (('ixor', a, a), 0),
  94    (('inot', ('inot', a)), a),
  95    # DeMorgan's Laws
  96    (('iand', ('inot', a), ('inot', b)), ('inot', ('ior',  a, b))),
  97    (('ior',  ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
  98    # Shift optimizations
  99    (('ishl', 0, a), 0),
 100    (('ishl', a, 0), a),
 101    (('ishr', 0, a), 0),
 102    (('ishr', a, 0), a),
 103    (('ushr', 0, a), 0),
 104    (('ushr', a, 0), 0),
 105    # Exponential/logarithmic identities
 106    (('fexp2', ('flog2', a)), a), # 2^lg2(a) = a
 107    (('fexp',  ('flog',  a)), a), # e^ln(a)  = a
 108    (('flog2', ('fexp2', a)), a), # lg2(2^a) = a
 109    (('flog',  ('fexp',  a)), a), # ln(e^a)  = a
 110    (('fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b)), # 2^(lg2(a)*b) = a^b
 111    (('fexp',  ('fmul', ('flog', a), b)),  ('fpow', a, b)), # e^(ln(a)*b) = a^b
 112    (('fpow', a, 1.0), a),
 113    (('fpow', a, 2.0), ('fmul', a, a)),
 114    (('fpow', 2.0, a), ('fexp2', a)),
 115    # Division and reciprocal
 116    (('fdiv', 1.0, a), ('frcp', a)),
 117    (('frcp', ('frcp', a)), a),
 118    (('frcp', ('fsqrt', a)), ('frsq', a)),
 119    (('frcp', ('frsq', a)), ('fsqrt', a)),
 120    # Boolean simplifications
 121    (('ine', 'a@bool', 0), 'a'),
 122    (('ieq', 'a@bool', 0), ('inot', 'a')),
 123    (('bcsel', 'a@bool', True, False), 'a'),
 124    (('bcsel', 'a@bool', False, True), ('inot', 'a')),
 125
 126 # This one may not be exact
 127    (('feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
 128 ]
 129
 130 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()