nir: Lower flrp with Boolean interpolator to bcsel
[mesa.git] / src / compiler / 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 (('usadd_4x8', a, 0), a),
60 (('usadd_4x8', a, ~0), ~0),
61 (('fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
62 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
63 (('fadd', ('fneg', a), a), 0.0),
64 (('iadd', ('ineg', a), a), 0),
65 (('iadd', ('ineg', a), ('iadd', a, b)), b),
66 (('iadd', a, ('iadd', ('ineg', a), b)), b),
67 (('fadd', ('fneg', a), ('fadd', a, b)), b),
68 (('fadd', a, ('fadd', ('fneg', a), b)), b),
69 (('fmul', a, 0.0), 0.0),
70 (('imul', a, 0), 0),
71 (('umul_unorm_4x8', a, 0), 0),
72 (('umul_unorm_4x8', a, ~0), a),
73 (('fmul', a, 1.0), a),
74 (('imul', a, 1), a),
75 (('fmul', a, -1.0), ('fneg', a)),
76 (('imul', a, -1), ('ineg', a)),
77 (('ffma', 0.0, a, b), b),
78 (('ffma', a, 0.0, b), b),
79 (('ffma', a, b, 0.0), ('fmul', a, b)),
80 (('ffma', a, 1.0, b), ('fadd', a, b)),
81 (('ffma', 1.0, a, b), ('fadd', a, b)),
82 (('flrp', a, b, 0.0), a),
83 (('flrp', a, b, 1.0), b),
84 (('flrp', a, a, b), a),
85 (('flrp', 0.0, a, b), ('fmul', a, b)),
86 (('flrp', a, b, ('b2f', c)), ('bcsel', c, b, a), 'options->lower_flrp'),
87 (('flrp', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp'),
88 (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'),
89 (('fadd', ('fmul', a, ('fadd', 1.0, ('fneg', ('b2f', c)))), ('fmul', b, ('b2f', c))), ('bcsel', c, b, a), 'options->lower_flrp'),
90 (('fadd', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp'),
91 (('fadd', a, ('fmul', ('b2f', c), ('fadd', b, ('fneg', a)))), ('bcsel', c, b, a), 'options->lower_flrp'),
92 (('fadd', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp'),
93 (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options->lower_ffma'),
94 (('fadd', ('fmul', a, b), c), ('ffma', a, b, c), '!options->lower_ffma'),
95 # Comparison simplifications
96 (('inot', ('flt', a, b)), ('fge', a, b)),
97 (('inot', ('fge', a, b)), ('flt', a, b)),
98 (('inot', ('feq', a, b)), ('fne', a, b)),
99 (('inot', ('fne', a, b)), ('feq', a, b)),
100 (('inot', ('ilt', a, b)), ('ige', a, b)),
101 (('inot', ('ige', a, b)), ('ilt', a, b)),
102 (('inot', ('ieq', a, b)), ('ine', a, b)),
103 (('inot', ('ine', a, b)), ('ieq', a, b)),
104 (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
105 (('bcsel', ('flt', a, b), a, b), ('fmin', a, b)),
106 (('bcsel', ('flt', a, b), b, a), ('fmax', a, b)),
107 (('bcsel', ('inot', 'a@bool'), b, c), ('bcsel', a, c, b)),
108 (('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)),
109 (('fmin', a, a), a),
110 (('fmax', a, a), a),
111 (('imin', a, a), a),
112 (('imax', a, a), a),
113 (('umin', a, a), a),
114 (('umax', a, a), a),
115 (('fmin', ('fmax', a, 0.0), 1.0), ('fsat', a), '!options->lower_fsat'),
116 (('fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
117 (('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
118 (('fsat', ('fsat', a)), ('fsat', a)),
119 (('fmin', ('fmax', ('fmin', ('fmax', a, 0.0), 1.0), 0.0), 1.0), ('fmin', ('fmax', a, 0.0), 1.0)),
120 (('ior', ('flt', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
121 (('ior', ('flt', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
122 (('ior', ('fge', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
123 (('ior', ('fge', a, c), ('fge', b, c)), ('fge', ('fmax', a, b), c)),
124 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
125 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
126 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
127 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
128 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
129 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
130 # Emulating booleans
131 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
132 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
133 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
134 (('iand', 'a@bool', 1.0), ('b2f', a)),
135 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
136 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
137 # Comparison with the same args. Note that these are not done for
138 # the float versions because NaN always returns false on float
139 # inequalities.
140 (('ilt', a, a), False),
141 (('ige', a, a), True),
142 (('ieq', a, a), True),
143 (('ine', a, a), False),
144 (('ult', a, a), False),
145 (('uge', a, a), True),
146 # Logical and bit operations
147 (('fand', a, 0.0), 0.0),
148 (('iand', a, a), a),
149 (('iand', a, ~0), a),
150 (('iand', a, 0), 0),
151 (('ior', a, a), a),
152 (('ior', a, 0), a),
153 (('fxor', a, a), 0.0),
154 (('ixor', a, a), 0),
155 (('fxor', a, 0.0), a),
156 (('ixor', a, 0), a),
157 (('inot', ('inot', a)), a),
158 # DeMorgan's Laws
159 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
160 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
161 # Shift optimizations
162 (('ishl', 0, a), 0),
163 (('ishl', a, 0), a),
164 (('ishr', 0, a), 0),
165 (('ishr', a, 0), a),
166 (('ushr', 0, a), 0),
167 (('ushr', a, 0), a),
168 (('iand', 0xff, ('ushr', a, 24)), ('ushr', a, 24)),
169 (('iand', 0xffff, ('ushr', a, 16)), ('ushr', a, 16)),
170 # Exponential/logarithmic identities
171 (('fexp2', ('flog2', a)), a), # 2^lg2(a) = a
172 (('flog2', ('fexp2', a)), a), # lg2(2^a) = a
173 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
174 (('fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
175 (('fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
176 ('fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
177 (('fpow', a, 1.0), a),
178 (('fpow', a, 2.0), ('fmul', a, a)),
179 (('fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
180 (('fpow', 2.0, a), ('fexp2', a)),
181 (('fpow', ('fpow', a, 2.2), 0.454545), a),
182 (('fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
183 (('fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
184 (('frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
185 (('frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
186 (('flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
187 (('flog2', ('frcp', a)), ('fneg', ('flog2', a))),
188 (('flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
189 (('flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
190 (('fadd', ('flog2', a), ('flog2', b)), ('flog2', ('fmul', a, b))),
191 (('fadd', ('flog2', a), ('fneg', ('flog2', b))), ('flog2', ('fdiv', a, b))),
192 (('fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
193 # Division and reciprocal
194 (('fdiv', 1.0, a), ('frcp', a)),
195 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
196 (('frcp', ('frcp', a)), a),
197 (('frcp', ('fsqrt', a)), ('frsq', a)),
198 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
199 (('frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
200 # Boolean simplifications
201 (('ieq', 'a@bool', True), a),
202 (('ine', 'a@bool', True), ('inot', a)),
203 (('ine', 'a@bool', False), a),
204 (('ieq', 'a@bool', False), ('inot', 'a')),
205 (('bcsel', a, True, False), ('ine', a, 0)),
206 (('bcsel', a, False, True), ('ieq', a, 0)),
207 (('bcsel', True, b, c), b),
208 (('bcsel', False, b, c), c),
209 # The result of this should be hit by constant propagation and, in the
210 # next round of opt_algebraic, get picked up by one of the above two.
211 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
212
213 (('bcsel', a, b, b), b),
214 (('fcsel', a, b, b), b),
215
216 # Conversions
217 (('i2b', ('b2i', a)), a),
218 (('f2i', ('ftrunc', a)), ('f2i', a)),
219 (('f2u', ('ftrunc', a)), ('f2u', a)),
220
221 # Byte extraction
222 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
223 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
224 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
225 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
226
227 # Word extraction
228 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
229 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
230
231 # Subtracts
232 (('fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
233 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
234 (('ussub_4x8', a, 0), a),
235 (('ussub_4x8', a, ~0), 0),
236 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
237 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
238 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
239 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
240 (('fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
241 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
242 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
243 (('iabs', ('isub', 0, a)), ('iabs', a)),
244
245 # Misc. lowering
246 (('fmod', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod'),
247 (('uadd_carry', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
248 (('usub_borrow', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
249
250 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
251 ('bcsel', ('ilt', 31, 'bits'), 'insert',
252 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
253 'options->lower_bitfield_insert'),
254
255 (('ibitfield_extract', 'value', 'offset', 'bits'),
256 ('bcsel', ('ilt', 31, 'bits'), 'value',
257 ('ibfe', 'value', 'offset', 'bits')),
258 'options->lower_bitfield_extract'),
259
260 (('ubitfield_extract', 'value', 'offset', 'bits'),
261 ('bcsel', ('ult', 31, 'bits'), 'value',
262 ('ubfe', 'value', 'offset', 'bits')),
263 'options->lower_bitfield_extract'),
264
265 (('extract_i8', a, b),
266 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
267 'options->lower_extract_byte'),
268
269 (('extract_u8', a, b),
270 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
271 'options->lower_extract_byte'),
272
273 (('extract_i16', a, b),
274 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
275 'options->lower_extract_word'),
276
277 (('extract_u16', a, b),
278 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
279 'options->lower_extract_word'),
280
281 (('pack_unorm_2x16', 'v'),
282 ('pack_uvec2_to_uint',
283 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
284 'options->lower_pack_unorm_2x16'),
285
286 (('pack_unorm_4x8', 'v'),
287 ('pack_uvec4_to_uint',
288 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
289 'options->lower_pack_unorm_4x8'),
290
291 (('pack_snorm_2x16', 'v'),
292 ('pack_uvec2_to_uint',
293 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
294 'options->lower_pack_snorm_2x16'),
295
296 (('pack_snorm_4x8', 'v'),
297 ('pack_uvec4_to_uint',
298 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
299 'options->lower_pack_snorm_4x8'),
300
301 (('unpack_unorm_2x16', 'v'),
302 ('fdiv', ('u2f', ('vec2', ('extract_u16', 'v', 0),
303 ('extract_u16', 'v', 1))),
304 65535.0),
305 'options->lower_unpack_unorm_2x16'),
306
307 (('unpack_unorm_4x8', 'v'),
308 ('fdiv', ('u2f', ('vec4', ('extract_u8', 'v', 0),
309 ('extract_u8', 'v', 1),
310 ('extract_u8', 'v', 2),
311 ('extract_u8', 'v', 3))),
312 255.0),
313 'options->lower_unpack_unorm_4x8'),
314
315 (('unpack_snorm_2x16', 'v'),
316 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec2', ('extract_i16', 'v', 0),
317 ('extract_i16', 'v', 1))),
318 32767.0))),
319 'options->lower_unpack_snorm_2x16'),
320
321 (('unpack_snorm_4x8', 'v'),
322 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec4', ('extract_i8', 'v', 0),
323 ('extract_i8', 'v', 1),
324 ('extract_i8', 'v', 2),
325 ('extract_i8', 'v', 3))),
326 127.0))),
327 'options->lower_unpack_snorm_4x8'),
328 ]
329
330 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
331 def bitfield_reverse(u):
332 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
333 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
334 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
335 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
336 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
337
338 return step5
339
340 optimizations += [(bitfield_reverse('x'), ('bitfield_reverse', 'x'))]
341
342
343 # Add optimizations to handle the case where the result of a ternary is
344 # compared to a constant. This way we can take things like
345 #
346 # (a ? 0 : 1) > 0
347 #
348 # and turn it into
349 #
350 # a ? (0 > 0) : (1 > 0)
351 #
352 # which constant folding will eat for lunch. The resulting ternary will
353 # further get cleaned up by the boolean reductions above and we will be
354 # left with just the original variable "a".
355 for op in ['flt', 'fge', 'feq', 'fne',
356 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
357 optimizations += [
358 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
359 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
360 ((op, '#d', ('bcsel', a, '#b', '#c')),
361 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
362 ]
363
364 # This section contains "late" optimizations that should be run after the
365 # regular optimizations have finished. Optimizations should go here if
366 # they help code generation but do not necessarily produce code that is
367 # more easily optimizable.
368 late_optimizations = [
369 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
370 (('fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
371 (('feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
372 (('fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
373 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
374 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
375 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
376 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
377 ]
378
379 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
380 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
381 late_optimizations).render()