85cdc7bdaf9072d0aa0b8c6c783840b81d31a490
[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 # If the opcode in a search expression is prefixed by a '~' character, this
42 # indicates that the operation is inexact. Such operations will only get
43 # applied to SSA values that do not have the exact bit set. This should be
44 # used by by any optimizations that are not bit-for-bit exact. It should not,
45 # however, be used for backend-requested lowering operations as those need to
46 # happen regardless of precision.
47 #
48 # Variable names are specified as "[#]name[@type][(cond)]" where "#" inicates
49 # that the given variable will only match constants and the type indicates that
50 # the given variable will only match values from ALU instructions with the
51 # given output type, and (cond) specifies an additional condition function
52 # (see nir_search_helpers.h).
53 #
54 # For constants, you have to be careful to make sure that it is the right
55 # type because python is unaware of the source and destination types of the
56 # opcodes.
57 #
58 # All expression types can have a bit-size specified. For opcodes, this
59 # looks like "op@32", for variables it is "a@32" or "a@uint32" to specify a
60 # type and size, and for literals, you can write "2.0@32". In the search half
61 # of the expression this indicates that it should only match that particular
62 # bit-size. In the replace half of the expression this indicates that the
63 # constructed value should have that bit-size.
64
65 optimizations = [
66
67 (('imul', a, '#b@32(is_pos_power_of_two)'), ('ishl', a, ('find_lsb', b))),
68 (('imul', a, '#b@32(is_neg_power_of_two)'), ('ineg', ('ishl', a, ('find_lsb', ('iabs', b))))),
69 (('udiv', a, 1), a),
70 (('idiv', a, 1), a),
71 (('umod', a, 1), 0),
72 (('imod', a, 1), 0),
73 (('udiv', a, '#b@32(is_pos_power_of_two)'), ('ushr', a, ('find_lsb', b))),
74 (('idiv', a, '#b@32(is_pos_power_of_two)'), ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', b))), 'options->lower_idiv'),
75 (('idiv', a, '#b@32(is_neg_power_of_two)'), ('ineg', ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', ('iabs', b))))), 'options->lower_idiv'),
76 (('umod', a, '#b(is_pos_power_of_two)'), ('iand', a, ('isub', b, 1))),
77
78 (('fneg', ('fneg', a)), a),
79 (('ineg', ('ineg', a)), a),
80 (('fabs', ('fabs', a)), ('fabs', a)),
81 (('fabs', ('fneg', a)), ('fabs', a)),
82 (('fabs', ('u2f', a)), ('u2f', a)),
83 (('iabs', ('iabs', a)), ('iabs', a)),
84 (('iabs', ('ineg', a)), ('iabs', a)),
85 (('~fadd', a, 0.0), a),
86 (('iadd', a, 0), a),
87 (('usadd_4x8', a, 0), a),
88 (('usadd_4x8', a, ~0), ~0),
89 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
90 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
91 (('~fadd', ('fneg', a), a), 0.0),
92 (('iadd', ('ineg', a), a), 0),
93 (('iadd', ('ineg', a), ('iadd', a, b)), b),
94 (('iadd', a, ('iadd', ('ineg', a), b)), b),
95 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
96 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
97 (('~fmul', a, 0.0), 0.0),
98 (('imul', a, 0), 0),
99 (('umul_unorm_4x8', a, 0), 0),
100 (('umul_unorm_4x8', a, ~0), a),
101 (('fmul', a, 1.0), a),
102 (('imul', a, 1), a),
103 (('fmul', a, -1.0), ('fneg', a)),
104 (('imul', a, -1), ('ineg', a)),
105 (('~ffma', 0.0, a, b), b),
106 (('~ffma', a, 0.0, b), b),
107 (('~ffma', a, b, 0.0), ('fmul', a, b)),
108 (('ffma', a, 1.0, b), ('fadd', a, b)),
109 (('ffma', 1.0, a, b), ('fadd', a, b)),
110 (('~flrp', a, b, 0.0), a),
111 (('~flrp', a, b, 1.0), b),
112 (('~flrp', a, a, b), a),
113 (('~flrp', 0.0, a, b), ('fmul', a, b)),
114 (('~flrp', a, b, ('b2f', c)), ('bcsel', c, b, a), 'options->lower_flrp32'),
115 (('flrp@32', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp32'),
116 (('flrp@64', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp64'),
117 (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'),
118 (('~fadd', ('fmul', a, ('fadd', 1.0, ('fneg', ('b2f', c)))), ('fmul', b, ('b2f', c))), ('bcsel', c, b, a), 'options->lower_flrp32'),
119 (('~fadd@32', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp32'),
120 (('~fadd@64', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp64'),
121 (('~fadd', a, ('fmul', ('b2f', c), ('fadd', b, ('fneg', a)))), ('bcsel', c, b, a), 'options->lower_flrp32'),
122 (('~fadd@32', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp32'),
123 (('~fadd@64', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp64'),
124 (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options->lower_ffma'),
125 (('~fadd', ('fmul', a, b), c), ('ffma', a, b, c), 'options->fuse_ffma'),
126
127 # (a * #b + #c) << #d
128 # ((a * #b) << #d) + (#c << #d)
129 # (a * (#b << #d)) + (#c << #d)
130 (('ishl', ('iadd', ('imul', a, '#b'), '#c'), '#d'),
131 ('iadd', ('imul', a, ('ishl', b, d)), ('ishl', c, d))),
132
133 # (a * #b) << #c
134 # a * (#b << #c)
135 (('ishl', ('imul', a, '#b'), '#c'), ('imul', a, ('ishl', b, c))),
136
137 # Comparison simplifications
138 (('~inot', ('flt', a, b)), ('fge', a, b)),
139 (('~inot', ('fge', a, b)), ('flt', a, b)),
140 (('~inot', ('feq', a, b)), ('fne', a, b)),
141 (('~inot', ('fne', a, b)), ('feq', a, b)),
142 (('inot', ('ilt', a, b)), ('ige', a, b)),
143 (('inot', ('ige', a, b)), ('ilt', a, b)),
144 (('inot', ('ieq', a, b)), ('ine', a, b)),
145 (('inot', ('ine', a, b)), ('ieq', a, b)),
146
147 # 0.0 >= b2f(a)
148 # b2f(a) <= 0.0
149 # b2f(a) == 0.0 because b2f(a) can only be 0 or 1
150 # inot(a)
151 (('fge', 0.0, ('b2f', a)), ('inot', a)),
152
153 (('fge', ('fneg', ('b2f', a)), 0.0), ('inot', a)),
154
155 # 0.0 < fabs(a)
156 # fabs(a) > 0.0
157 # fabs(a) != 0.0 because fabs(a) must be >= 0
158 # a != 0.0
159 (('flt', 0.0, ('fabs', a)), ('fne', a, 0.0)),
160
161 (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
162 (('bcsel', ('flt', b, a), b, a), ('fmin', a, b)),
163 (('bcsel', ('flt', a, b), b, a), ('fmax', a, b)),
164 (('bcsel', ('inot', a), b, c), ('bcsel', a, c, b)),
165 (('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)),
166 (('bcsel', a, True, 'b@bool'), ('ior', a, b)),
167 (('fmin', a, a), a),
168 (('fmax', a, a), a),
169 (('imin', a, a), a),
170 (('imax', a, a), a),
171 (('umin', a, a), a),
172 (('umax', a, a), a),
173 (('~fmin', ('fmax', a, 0.0), 1.0), ('fsat', a), '!options->lower_fsat'),
174 (('~fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
175 (('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
176 (('fsat', ('fsat', a)), ('fsat', a)),
177 (('fmin', ('fmax', ('fmin', ('fmax', a, b), c), b), c), ('fmin', ('fmax', a, b), c)),
178 (('imin', ('imax', ('imin', ('imax', a, b), c), b), c), ('imin', ('imax', a, b), c)),
179 (('umin', ('umax', ('umin', ('umax', a, b), c), b), c), ('umin', ('umax', a, b), c)),
180 (('fmax', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmax', a, b))),
181 (('fmin', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmin', a, b))),
182 (('extract_u8', ('imin', ('imax', a, 0), 0xff), 0), ('imin', ('imax', a, 0), 0xff)),
183 (('~ior', ('flt', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
184 (('~ior', ('flt', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
185 (('~ior', ('fge', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
186 (('~ior', ('fge', a, c), ('fge', b, c)), ('fge', ('fmax', a, b), c)),
187 (('fabs', ('slt', a, b)), ('slt', a, b)),
188 (('fabs', ('sge', a, b)), ('sge', a, b)),
189 (('fabs', ('seq', a, b)), ('seq', a, b)),
190 (('fabs', ('sne', a, b)), ('sne', a, b)),
191 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
192 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
193 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
194 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
195 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
196 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
197 # Emulating booleans
198 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
199 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
200 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
201 (('iand', 'a@bool', 1.0), ('b2f', a)),
202 # True/False are ~0 and 0 in NIR. b2i of True is 1, and -1 is ~0 (True).
203 (('ineg', ('b2i', a)), a),
204 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
205 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
206 # Comparison with the same args. Note that these are not done for
207 # the float versions because NaN always returns false on float
208 # inequalities.
209 (('ilt', a, a), False),
210 (('ige', a, a), True),
211 (('ieq', a, a), True),
212 (('ine', a, a), False),
213 (('ult', a, a), False),
214 (('uge', a, a), True),
215 # Logical and bit operations
216 (('fand', a, 0.0), 0.0),
217 (('iand', a, a), a),
218 (('iand', a, ~0), a),
219 (('iand', a, 0), 0),
220 (('ior', a, a), a),
221 (('ior', a, 0), a),
222 (('ior', a, True), True),
223 (('fxor', a, a), 0.0),
224 (('ixor', a, a), 0),
225 (('ixor', a, 0), a),
226 (('inot', ('inot', a)), a),
227 # DeMorgan's Laws
228 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
229 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
230 # Shift optimizations
231 (('ishl', 0, a), 0),
232 (('ishl', a, 0), a),
233 (('ishr', 0, a), 0),
234 (('ishr', a, 0), a),
235 (('ushr', 0, a), 0),
236 (('ushr', a, 0), a),
237 (('iand', 0xff, ('ushr', a, 24)), ('ushr', a, 24)),
238 (('iand', 0xffff, ('ushr', a, 16)), ('ushr', a, 16)),
239 # Exponential/logarithmic identities
240 (('~fexp2', ('flog2', a)), a), # 2^lg2(a) = a
241 (('~flog2', ('fexp2', a)), a), # lg2(2^a) = a
242 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
243 (('~fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
244 (('~fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
245 ('~fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
246 (('~fpow', a, 1.0), a),
247 (('~fpow', a, 2.0), ('fmul', a, a)),
248 (('~fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
249 (('~fpow', 2.0, a), ('fexp2', a)),
250 (('~fpow', ('fpow', a, 2.2), 0.454545), a),
251 (('~fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
252 (('~fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
253 (('~frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
254 (('~frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
255 (('~flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
256 (('~flog2', ('frcp', a)), ('fneg', ('flog2', a))),
257 (('~flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
258 (('~flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
259 (('~fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
260 # Division and reciprocal
261 (('~fdiv', 1.0, a), ('frcp', a)),
262 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
263 (('~frcp', ('frcp', a)), a),
264 (('~frcp', ('fsqrt', a)), ('frsq', a)),
265 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
266 (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
267 # Boolean simplifications
268 (('ieq', 'a@bool', True), a),
269 (('ine', 'a@bool', True), ('inot', a)),
270 (('ine', 'a@bool', False), a),
271 (('ieq', 'a@bool', False), ('inot', 'a')),
272 (('bcsel', a, True, False), a),
273 (('bcsel', a, False, True), ('inot', a)),
274 (('bcsel@32', a, 1.0, 0.0), ('b2f', a)),
275 (('bcsel@32', a, 0.0, 1.0), ('b2f', ('inot', a))),
276 (('bcsel@32', a, -1.0, -0.0), ('fneg', ('b2f', a))),
277 (('bcsel@32', a, -0.0, -1.0), ('fneg', ('b2f', ('inot', a)))),
278 (('bcsel', True, b, c), b),
279 (('bcsel', False, b, c), c),
280 # The result of this should be hit by constant propagation and, in the
281 # next round of opt_algebraic, get picked up by one of the above two.
282 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
283
284 (('bcsel', a, b, b), b),
285 (('fcsel', a, b, b), b),
286
287 # Conversions
288 (('i2b', ('b2i', a)), a),
289 (('f2i', ('ftrunc', a)), ('f2i', a)),
290 (('f2u', ('ftrunc', a)), ('f2u', a)),
291 (('i2b', ('ineg', a)), ('i2b', a)),
292 (('i2b', ('iabs', a)), ('i2b', a)),
293 (('fabs', ('b2f', a)), ('b2f', a)),
294 (('iabs', ('b2i', a)), ('b2i', a)),
295
296 # Byte extraction
297 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
298 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
299 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
300 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
301
302 # Word extraction
303 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
304 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
305
306 # Subtracts
307 (('~fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
308 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
309 (('ussub_4x8', a, 0), a),
310 (('ussub_4x8', a, ~0), 0),
311 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
312 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
313 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
314 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
315 (('~fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
316 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
317 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
318 (('iabs', ('isub', 0, a)), ('iabs', a)),
319
320 # Propagate negation up multiplication chains
321 (('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
322 (('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
323
324 # Reassociate constants in add/mul chains so they can be folded together.
325 # For now, we only handle cases where the constants are separated by
326 # a single non-constant. We could do better eventually.
327 (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
328 (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
329 (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
330 (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
331
332 # Misc. lowering
333 (('fmod@32', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod32'),
334 (('fmod@64', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod64'),
335 (('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod32'),
336 (('uadd_carry@32', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
337 (('usub_borrow@32', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
338
339 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
340 ('bcsel', ('ilt', 31, 'bits'), 'insert',
341 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
342 'options->lower_bitfield_insert'),
343
344 (('ibitfield_extract', 'value', 'offset', 'bits'),
345 ('bcsel', ('ilt', 31, 'bits'), 'value',
346 ('ibfe', 'value', 'offset', 'bits')),
347 'options->lower_bitfield_extract'),
348
349 (('ubitfield_extract', 'value', 'offset', 'bits'),
350 ('bcsel', ('ult', 31, 'bits'), 'value',
351 ('ubfe', 'value', 'offset', 'bits')),
352 'options->lower_bitfield_extract'),
353
354 (('extract_i8', a, b),
355 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
356 'options->lower_extract_byte'),
357
358 (('extract_u8', a, b),
359 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
360 'options->lower_extract_byte'),
361
362 (('extract_i16', a, b),
363 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
364 'options->lower_extract_word'),
365
366 (('extract_u16', a, b),
367 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
368 'options->lower_extract_word'),
369
370 (('pack_unorm_2x16', 'v'),
371 ('pack_uvec2_to_uint',
372 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
373 'options->lower_pack_unorm_2x16'),
374
375 (('pack_unorm_4x8', 'v'),
376 ('pack_uvec4_to_uint',
377 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
378 'options->lower_pack_unorm_4x8'),
379
380 (('pack_snorm_2x16', 'v'),
381 ('pack_uvec2_to_uint',
382 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
383 'options->lower_pack_snorm_2x16'),
384
385 (('pack_snorm_4x8', 'v'),
386 ('pack_uvec4_to_uint',
387 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
388 'options->lower_pack_snorm_4x8'),
389
390 (('unpack_unorm_2x16', 'v'),
391 ('fdiv', ('u2f', ('vec2', ('extract_u16', 'v', 0),
392 ('extract_u16', 'v', 1))),
393 65535.0),
394 'options->lower_unpack_unorm_2x16'),
395
396 (('unpack_unorm_4x8', 'v'),
397 ('fdiv', ('u2f', ('vec4', ('extract_u8', 'v', 0),
398 ('extract_u8', 'v', 1),
399 ('extract_u8', 'v', 2),
400 ('extract_u8', 'v', 3))),
401 255.0),
402 'options->lower_unpack_unorm_4x8'),
403
404 (('unpack_snorm_2x16', 'v'),
405 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec2', ('extract_i16', 'v', 0),
406 ('extract_i16', 'v', 1))),
407 32767.0))),
408 'options->lower_unpack_snorm_2x16'),
409
410 (('unpack_snorm_4x8', 'v'),
411 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec4', ('extract_i8', 'v', 0),
412 ('extract_i8', 'v', 1),
413 ('extract_i8', 'v', 2),
414 ('extract_i8', 'v', 3))),
415 127.0))),
416 'options->lower_unpack_snorm_4x8'),
417 ]
418
419 def fexp2i(exp, bits):
420 # We assume that exp is already in the right range.
421 if bits == 32:
422 return ('ishl', ('iadd', exp, 127), 23)
423 elif bits == 64:
424 return ('pack_double_2x32_split', 0, ('ishl', ('iadd', exp, 1023), 20))
425 else:
426 assert False
427
428 def ldexp(f, exp, bits):
429 # First, we clamp exp to a reasonable range. The maximum possible range
430 # for a normal exponent is [-126, 127] and, throwing in denormals, you get
431 # a maximum range of [-149, 127]. This means that we can potentially have
432 # a swing of +-276. If you start with FLT_MAX, you actually have to do
433 # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
434 # spec, on the other hand, only requires that we handle an exponent value
435 # in the range [-126, 128]. This implementation is *mostly* correct; it
436 # handles a range on exp of [-252, 254] which allows you to create any
437 # value (including denorms if the hardware supports it) and to adjust the
438 # exponent of any normal value to anything you want.
439 if bits == 32:
440 exp = ('imin', ('imax', exp, -252), 254)
441 elif bits == 64:
442 exp = ('imin', ('imax', exp, -2044), 2046)
443 else:
444 assert False
445
446 # Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
447 # (We use ishr which isn't the same for -1, but the -1 case still works
448 # since we use exp-exp/2 as the second exponent.) While the spec
449 # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
450 # work with denormals and doesn't allow for the full swing in exponents
451 # that you can get with normalized values. Instead, we create two powers
452 # of two and multiply by them each in turn. That way the effective range
453 # of our exponent is doubled.
454 pow2_1 = fexp2i(('ishr', exp, 1), bits)
455 pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)), bits)
456 return ('fmul', ('fmul', f, pow2_1), pow2_2)
457
458 optimizations += [
459 (('ldexp@32', 'x', 'exp'), ldexp('x', 'exp', 32)),
460 (('ldexp@64', 'x', 'exp'), ldexp('x', 'exp', 64)),
461 ]
462
463 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
464 def bitfield_reverse(u):
465 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
466 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
467 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
468 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
469 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
470
471 return step5
472
473 optimizations += [(bitfield_reverse('x@32'), ('bitfield_reverse', 'x'))]
474
475 # For any float comparison operation, "cmp", if you have "a == a && a cmp b"
476 # then the "a == a" is redundant because it's equivalent to "a is not NaN"
477 # and, if a is a NaN then the second comparison will fail anyway.
478 for op in ['flt', 'fge', 'feq']:
479 optimizations += [
480 (('iand', ('feq', a, a), (op, a, b)), (op, a, b)),
481 (('iand', ('feq', a, a), (op, b, a)), (op, b, a)),
482 ]
483
484 # Add optimizations to handle the case where the result of a ternary is
485 # compared to a constant. This way we can take things like
486 #
487 # (a ? 0 : 1) > 0
488 #
489 # and turn it into
490 #
491 # a ? (0 > 0) : (1 > 0)
492 #
493 # which constant folding will eat for lunch. The resulting ternary will
494 # further get cleaned up by the boolean reductions above and we will be
495 # left with just the original variable "a".
496 for op in ['flt', 'fge', 'feq', 'fne',
497 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
498 optimizations += [
499 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
500 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
501 ((op, '#d', ('bcsel', a, '#b', '#c')),
502 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
503 ]
504
505 # This section contains "late" optimizations that should be run after the
506 # regular optimizations have finished. Optimizations should go here if
507 # they help code generation but do not necessarily produce code that is
508 # more easily optimizable.
509 late_optimizations = [
510 # Most of these optimizations aren't quite safe when you get infinity or
511 # Nan involved but the first one should be fine.
512 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
513 (('~fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
514 (('~feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
515 (('~fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
516
517 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
518 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
519 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
520 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
521 ]
522
523 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
524 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
525 late_optimizations).render()