nir: Add a descriptor_set field to nir_variable
[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]" where "#" inicates that
49 # 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.
52 #
53 # For constants, you have to be careful to make sure that it is the right
54 # type because python is unaware of the source and destination types of the
55 # opcodes.
56
57 optimizations = [
58 (('fneg', ('fneg', a)), a),
59 (('ineg', ('ineg', a)), a),
60 (('fabs', ('fabs', a)), ('fabs', a)),
61 (('fabs', ('fneg', a)), ('fabs', a)),
62 (('iabs', ('iabs', a)), ('iabs', a)),
63 (('iabs', ('ineg', a)), ('iabs', a)),
64 (('~fadd', a, 0.0), a),
65 (('iadd', a, 0), a),
66 (('usadd_4x8', a, 0), a),
67 (('usadd_4x8', a, ~0), ~0),
68 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
69 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
70 (('~fadd', ('fneg', a), a), 0.0),
71 (('iadd', ('ineg', a), a), 0),
72 (('iadd', ('ineg', a), ('iadd', a, b)), b),
73 (('iadd', a, ('iadd', ('ineg', a), b)), b),
74 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
75 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
76 (('~fmul', a, 0.0), 0.0),
77 (('imul', a, 0), 0),
78 (('umul_unorm_4x8', a, 0), 0),
79 (('umul_unorm_4x8', a, ~0), a),
80 (('fmul', a, 1.0), a),
81 (('imul', a, 1), a),
82 (('fmul', a, -1.0), ('fneg', a)),
83 (('imul', a, -1), ('ineg', a)),
84 (('~ffma', 0.0, a, b), b),
85 (('~ffma', a, 0.0, b), b),
86 (('~ffma', a, b, 0.0), ('fmul', a, b)),
87 (('ffma', a, 1.0, b), ('fadd', a, b)),
88 (('ffma', 1.0, a, b), ('fadd', a, b)),
89 (('~flrp', a, b, 0.0), a),
90 (('~flrp', a, b, 1.0), b),
91 (('~flrp', a, a, b), a),
92 (('~flrp', 0.0, a, b), ('fmul', a, b)),
93 (('~flrp', a, b, ('b2f', c)), ('bcsel', c, b, a), 'options->lower_flrp'),
94 (('flrp', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp'),
95 (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'),
96 (('~fadd', ('fmul', a, ('fadd', 1.0, ('fneg', ('b2f', c)))), ('fmul', b, ('b2f', c))), ('bcsel', c, b, a), 'options->lower_flrp'),
97 (('~fadd', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp'),
98 (('~fadd', a, ('fmul', ('b2f', c), ('fadd', b, ('fneg', a)))), ('bcsel', c, b, a), 'options->lower_flrp'),
99 (('~fadd', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp'),
100 (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options->lower_ffma'),
101 (('~fadd', ('fmul', a, b), c), ('ffma', a, b, c), '!options->lower_ffma'),
102 # Comparison simplifications
103 (('~inot', ('flt', a, b)), ('fge', a, b)),
104 (('~inot', ('fge', a, b)), ('flt', a, b)),
105 (('~inot', ('feq', a, b)), ('fne', a, b)),
106 (('~inot', ('fne', a, b)), ('feq', a, b)),
107 (('inot', ('ilt', a, b)), ('ige', a, b)),
108 (('inot', ('ige', a, b)), ('ilt', a, b)),
109 (('inot', ('ieq', a, b)), ('ine', a, b)),
110 (('inot', ('ine', a, b)), ('ieq', a, b)),
111
112 # 0.0 >= b2f(a)
113 # b2f(a) <= 0.0
114 # b2f(a) == 0.0 because b2f(a) can only be 0 or 1
115 # inot(a)
116 (('fge', 0.0, ('b2f', a)), ('inot', a)),
117
118 # 0.0 < fabs(a)
119 # fabs(a) > 0.0
120 # fabs(a) != 0.0 because fabs(a) must be >= 0
121 # a != 0.0
122 (('flt', 0.0, ('fabs', a)), ('fne', a, 0.0)),
123
124 (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
125 (('bcsel', ('flt', b, a), b, a), ('fmin', a, b)),
126 (('bcsel', ('flt', a, b), b, a), ('fmax', a, b)),
127 (('bcsel', ('inot', 'a@bool'), b, c), ('bcsel', a, c, b)),
128 (('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)),
129 (('bcsel', a, True, 'b@bool'), ('ior', a, b)),
130 (('fmin', a, a), a),
131 (('fmax', a, a), a),
132 (('imin', a, a), a),
133 (('imax', a, a), a),
134 (('umin', a, a), a),
135 (('umax', a, a), a),
136 (('~fmin', ('fmax', a, 0.0), 1.0), ('fsat', a), '!options->lower_fsat'),
137 (('~fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
138 (('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
139 (('fsat', ('fsat', a)), ('fsat', a)),
140 (('fmin', ('fmax', ('fmin', ('fmax', a, b), c), b), c), ('fmin', ('fmax', a, b), c)),
141 (('imin', ('imax', ('imin', ('imax', a, b), c), b), c), ('imin', ('imax', a, b), c)),
142 (('umin', ('umax', ('umin', ('umax', a, b), c), b), c), ('umin', ('umax', a, b), c)),
143 (('extract_u8', ('imin', ('imax', a, 0), 0xff), 0), ('imin', ('imax', a, 0), 0xff)),
144 (('~ior', ('flt', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
145 (('~ior', ('flt', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
146 (('~ior', ('fge', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
147 (('~ior', ('fge', a, c), ('fge', b, c)), ('fge', ('fmax', a, b), c)),
148 (('fabs', ('slt', a, b)), ('slt', a, b)),
149 (('fabs', ('sge', a, b)), ('sge', a, b)),
150 (('fabs', ('seq', a, b)), ('seq', a, b)),
151 (('fabs', ('sne', a, b)), ('sne', a, b)),
152 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
153 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
154 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
155 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
156 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
157 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
158 # Emulating booleans
159 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
160 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
161 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
162 (('iand', 'a@bool', 1.0), ('b2f', a)),
163 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
164 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
165 # Comparison with the same args. Note that these are not done for
166 # the float versions because NaN always returns false on float
167 # inequalities.
168 (('ilt', a, a), False),
169 (('ige', a, a), True),
170 (('ieq', a, a), True),
171 (('ine', a, a), False),
172 (('ult', a, a), False),
173 (('uge', a, a), True),
174 # Logical and bit operations
175 (('fand', a, 0.0), 0.0),
176 (('iand', a, a), a),
177 (('iand', a, ~0), a),
178 (('iand', a, 0), 0),
179 (('ior', a, a), a),
180 (('ior', a, 0), a),
181 (('fxor', a, a), 0.0),
182 (('ixor', a, a), 0),
183 (('ixor', a, 0), a),
184 (('inot', ('inot', a)), a),
185 # DeMorgan's Laws
186 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
187 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
188 # Shift optimizations
189 (('ishl', 0, a), 0),
190 (('ishl', a, 0), a),
191 (('ishr', 0, a), 0),
192 (('ishr', a, 0), a),
193 (('ushr', 0, a), 0),
194 (('ushr', a, 0), a),
195 (('iand', 0xff, ('ushr', a, 24)), ('ushr', a, 24)),
196 (('iand', 0xffff, ('ushr', a, 16)), ('ushr', a, 16)),
197 # Exponential/logarithmic identities
198 (('~fexp2', ('flog2', a)), a), # 2^lg2(a) = a
199 (('~flog2', ('fexp2', a)), a), # lg2(2^a) = a
200 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
201 (('~fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
202 (('~fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
203 ('~fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
204 (('~fpow', a, 1.0), a),
205 (('~fpow', a, 2.0), ('fmul', a, a)),
206 (('~fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
207 (('~fpow', 2.0, a), ('fexp2', a)),
208 (('~fpow', ('fpow', a, 2.2), 0.454545), a),
209 (('~fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
210 (('~fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
211 (('~frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
212 (('~frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
213 (('~flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
214 (('~flog2', ('frcp', a)), ('fneg', ('flog2', a))),
215 (('~flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
216 (('~flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
217 (('~fadd', ('flog2', a), ('flog2', b)), ('flog2', ('fmul', a, b))),
218 (('~fadd', ('flog2', a), ('fneg', ('flog2', b))), ('flog2', ('fdiv', a, b))),
219 (('~fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
220 # Division and reciprocal
221 (('~fdiv', 1.0, a), ('frcp', a)),
222 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
223 (('~frcp', ('frcp', a)), a),
224 (('~frcp', ('fsqrt', a)), ('frsq', a)),
225 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
226 (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
227 # Boolean simplifications
228 (('ieq', 'a@bool', True), a),
229 (('ine', 'a@bool', True), ('inot', a)),
230 (('ine', 'a@bool', False), a),
231 (('ieq', 'a@bool', False), ('inot', 'a')),
232 (('bcsel', a, True, False), ('ine', a, 0)),
233 (('bcsel', a, False, True), ('ieq', a, 0)),
234 (('bcsel', True, b, c), b),
235 (('bcsel', False, b, c), c),
236 # The result of this should be hit by constant propagation and, in the
237 # next round of opt_algebraic, get picked up by one of the above two.
238 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
239
240 (('bcsel', a, b, b), b),
241 (('fcsel', a, b, b), b),
242
243 # Conversions
244 (('i2b', ('b2i', a)), a),
245 (('f2i', ('ftrunc', a)), ('f2i', a)),
246 (('f2u', ('ftrunc', a)), ('f2u', a)),
247 (('i2b', ('ineg', a)), ('i2b', a)),
248 (('i2b', ('iabs', a)), ('i2b', a)),
249 (('fabs', ('b2f', a)), ('b2f', a)),
250 (('iabs', ('b2i', a)), ('b2i', a)),
251
252 # Byte extraction
253 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
254 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
255 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
256 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
257
258 # Word extraction
259 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
260 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
261
262 # Subtracts
263 (('~fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
264 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
265 (('ussub_4x8', a, 0), a),
266 (('ussub_4x8', a, ~0), 0),
267 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
268 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
269 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
270 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
271 (('~fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
272 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
273 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
274 (('iabs', ('isub', 0, a)), ('iabs', a)),
275
276 # Propagate negation up multiplication chains
277 (('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
278 (('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
279
280 # Reassociate constants in add/mul chains so they can be folded together.
281 # For now, we only handle cases where the constants are separated by
282 # a single non-constant. We could do better eventually.
283 (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
284 (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
285 (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
286 (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
287
288 # Misc. lowering
289 (('fmod', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod'),
290 (('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod'),
291 (('uadd_carry', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
292 (('usub_borrow', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
293
294 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
295 ('bcsel', ('ilt', 31, 'bits'), 'insert',
296 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
297 'options->lower_bitfield_insert'),
298
299 (('ibitfield_extract', 'value', 'offset', 'bits'),
300 ('bcsel', ('ilt', 31, 'bits'), 'value',
301 ('ibfe', 'value', 'offset', 'bits')),
302 'options->lower_bitfield_extract'),
303
304 (('ubitfield_extract', 'value', 'offset', 'bits'),
305 ('bcsel', ('ult', 31, 'bits'), 'value',
306 ('ubfe', 'value', 'offset', 'bits')),
307 'options->lower_bitfield_extract'),
308
309 (('extract_i8', a, b),
310 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
311 'options->lower_extract_byte'),
312
313 (('extract_u8', a, b),
314 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
315 'options->lower_extract_byte'),
316
317 (('extract_i16', a, b),
318 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
319 'options->lower_extract_word'),
320
321 (('extract_u16', a, b),
322 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
323 'options->lower_extract_word'),
324
325 (('pack_unorm_2x16', 'v'),
326 ('pack_uvec2_to_uint',
327 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
328 'options->lower_pack_unorm_2x16'),
329
330 (('pack_unorm_4x8', 'v'),
331 ('pack_uvec4_to_uint',
332 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
333 'options->lower_pack_unorm_4x8'),
334
335 (('pack_snorm_2x16', 'v'),
336 ('pack_uvec2_to_uint',
337 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
338 'options->lower_pack_snorm_2x16'),
339
340 (('pack_snorm_4x8', 'v'),
341 ('pack_uvec4_to_uint',
342 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
343 'options->lower_pack_snorm_4x8'),
344
345 (('unpack_unorm_2x16', 'v'),
346 ('fdiv', ('u2f', ('vec2', ('extract_u16', 'v', 0),
347 ('extract_u16', 'v', 1))),
348 65535.0),
349 'options->lower_unpack_unorm_2x16'),
350
351 (('unpack_unorm_4x8', 'v'),
352 ('fdiv', ('u2f', ('vec4', ('extract_u8', 'v', 0),
353 ('extract_u8', 'v', 1),
354 ('extract_u8', 'v', 2),
355 ('extract_u8', 'v', 3))),
356 255.0),
357 'options->lower_unpack_unorm_4x8'),
358
359 (('unpack_snorm_2x16', 'v'),
360 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec2', ('extract_i16', 'v', 0),
361 ('extract_i16', 'v', 1))),
362 32767.0))),
363 'options->lower_unpack_snorm_2x16'),
364
365 (('unpack_snorm_4x8', 'v'),
366 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec4', ('extract_i8', 'v', 0),
367 ('extract_i8', 'v', 1),
368 ('extract_i8', 'v', 2),
369 ('extract_i8', 'v', 3))),
370 127.0))),
371 'options->lower_unpack_snorm_4x8'),
372 ]
373
374 def fexp2i(exp):
375 # We assume that exp is already in the range [-126, 127].
376 return ('ishl', ('iadd', exp, 127), 23)
377
378 def ldexp32(f, exp):
379 # First, we clamp exp to a reasonable range. The maximum possible range
380 # for a normal exponent is [-126, 127] and, throwing in denormals, you get
381 # a maximum range of [-149, 127]. This means that we can potentially have
382 # a swing of +-276. If you start with FLT_MAX, you actually have to do
383 # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
384 # spec, on the other hand, only requires that we handle an exponent value
385 # in the range [-126, 128]. This implementation is *mostly* correct; it
386 # handles a range on exp of [-252, 254] which allows you to create any
387 # value (including denorms if the hardware supports it) and to adjust the
388 # exponent of any normal value to anything you want.
389 exp = ('imin', ('imax', exp, -252), 254)
390
391 # Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
392 # (We use ishr which isn't the same for -1, but the -1 case still works
393 # since we use exp-exp/2 as the second exponent.) While the spec
394 # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
395 # work with denormals and doesn't allow for the full swing in exponents
396 # that you can get with normalized values. Instead, we create two powers
397 # of two and multiply by them each in turn. That way the effective range
398 # of our exponent is doubled.
399 pow2_1 = fexp2i(('ishr', exp, 1))
400 pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)))
401 return ('fmul', ('fmul', f, pow2_1), pow2_2)
402
403 optimizations += [(('ldexp', 'x', 'exp'), ldexp32('x', 'exp'))]
404
405 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
406 def bitfield_reverse(u):
407 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
408 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
409 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
410 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
411 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
412
413 return step5
414
415 optimizations += [(bitfield_reverse('x'), ('bitfield_reverse', 'x'))]
416
417
418 # Add optimizations to handle the case where the result of a ternary is
419 # compared to a constant. This way we can take things like
420 #
421 # (a ? 0 : 1) > 0
422 #
423 # and turn it into
424 #
425 # a ? (0 > 0) : (1 > 0)
426 #
427 # which constant folding will eat for lunch. The resulting ternary will
428 # further get cleaned up by the boolean reductions above and we will be
429 # left with just the original variable "a".
430 for op in ['flt', 'fge', 'feq', 'fne',
431 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
432 optimizations += [
433 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
434 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
435 ((op, '#d', ('bcsel', a, '#b', '#c')),
436 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
437 ]
438
439 # This section contains "late" optimizations that should be run after the
440 # regular optimizations have finished. Optimizations should go here if
441 # they help code generation but do not necessarily produce code that is
442 # more easily optimizable.
443 late_optimizations = [
444 # Most of these optimizations aren't quite safe when you get infinity or
445 # Nan involved but the first one should be fine.
446 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
447 (('~fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
448 (('~feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
449 (('~fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
450
451 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
452 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
453 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
454 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
455 ]
456
457 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
458 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
459 late_optimizations).render()