Merge remote-tracking branch 'public/master' into vulkan
[mesa.git] / src / compiler / nir / nir_opt_algebraic.py
1 #! /usr/bin/env python
2 # -*- encoding: utf-8 -*-
3 #
4 # Copyright (C) 2014 Intel Corporation
5 #
6 # Permission is hereby granted, free of charge, to any person obtaining a
7 # copy of this software and associated documentation files (the "Software"),
8 # to deal in the Software without restriction, including without limitation
9 # the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 # and/or sell copies of the Software, and to permit persons to whom the
11 # Software is furnished to do so, subject to the following conditions:
12 #
13 # The above copyright notice and this permission notice (including the next
14 # paragraph) shall be included in all copies or substantial portions of the
15 # Software.
16 #
17 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
23 # IN THE SOFTWARE.
24 #
25 # Authors:
26 # Jason Ekstrand (jason@jlekstrand.net)
27
28 import nir_algebraic
29
30 # Convenience variables
31 a = 'a'
32 b = 'b'
33 c = 'c'
34 d = 'd'
35
36 # Written in the form (<search>, <replace>) where <search> is an expression
37 # and <replace> is either an expression or a value. An expression is
38 # defined as a tuple of the form ([~]<op>, <src0>, <src1>, <src2>, <src3>)
39 # where each source is either an expression or a value. A value can be
40 # either a numeric constant or a string representing a variable name.
41 #
42 # If the opcode in a search expression is prefixed by a '~' character, this
43 # indicates that the operation is inexact. Such operations will only get
44 # applied to SSA values that do not have the exact bit set. This should be
45 # used by by any optimizations that are not bit-for-bit exact. It should not,
46 # however, be used for backend-requested lowering operations as those need to
47 # happen regardless of precision.
48 #
49 # Variable names are specified as "[#]name[@type]" where "#" inicates that
50 # the given variable will only match constants and the type indicates that
51 # the given variable will only match values from ALU instructions with the
52 # given output type.
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 optimizations = [
59 (('fneg', ('fneg', a)), a),
60 (('ineg', ('ineg', a)), a),
61 (('fabs', ('fabs', a)), ('fabs', a)),
62 (('fabs', ('fneg', a)), ('fabs', a)),
63 (('iabs', ('iabs', a)), ('iabs', a)),
64 (('iabs', ('ineg', a)), ('iabs', a)),
65 (('~fadd', a, 0.0), a),
66 (('iadd', a, 0), a),
67 (('usadd_4x8', a, 0), a),
68 (('usadd_4x8', a, ~0), ~0),
69 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
70 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
71 (('~fadd', ('fneg', a), a), 0.0),
72 (('iadd', ('ineg', a), a), 0),
73 (('iadd', ('ineg', a), ('iadd', a, b)), b),
74 (('iadd', a, ('iadd', ('ineg', a), b)), b),
75 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
76 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
77 (('~fmul', a, 0.0), 0.0),
78 (('imul', a, 0), 0),
79 (('umul_unorm_4x8', a, 0), 0),
80 (('umul_unorm_4x8', a, ~0), a),
81 (('fmul', a, 1.0), a),
82 (('imul', a, 1), a),
83 (('fmul', a, -1.0), ('fneg', a)),
84 (('imul', a, -1), ('ineg', a)),
85 (('~ffma', 0.0, a, b), b),
86 (('~ffma', a, 0.0, b), b),
87 (('~ffma', a, b, 0.0), ('fmul', a, b)),
88 (('ffma', a, 1.0, b), ('fadd', a, b)),
89 (('ffma', 1.0, a, b), ('fadd', a, b)),
90 (('~flrp', a, b, 0.0), a),
91 (('~flrp', a, b, 1.0), b),
92 (('~flrp', a, a, b), a),
93 (('~flrp', 0.0, a, b), ('fmul', a, b)),
94 (('~flrp', a, b, ('b2f', c)), ('bcsel', c, b, a), 'options->lower_flrp'),
95 (('flrp', a, b, c), ('fadd', ('fmul', c, ('fsub', b, a)), a), 'options->lower_flrp'),
96 (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'),
97 (('~fadd', ('fmul', a, ('fadd', 1.0, ('fneg', ('b2f', c)))), ('fmul', b, ('b2f', c))), ('bcsel', c, b, a), 'options->lower_flrp'),
98 (('~fadd', ('fmul', a, ('fadd', 1.0, ('fneg', c ))), ('fmul', b, c )), ('flrp', a, b, c), '!options->lower_flrp'),
99 (('~fadd', a, ('fmul', ('b2f', c), ('fadd', b, ('fneg', a)))), ('bcsel', c, b, a), 'options->lower_flrp'),
100 (('~fadd', a, ('fmul', c , ('fadd', b, ('fneg', a)))), ('flrp', a, b, c), '!options->lower_flrp'),
101 (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options->lower_ffma'),
102 (('~fadd', ('fmul', a, b), c), ('ffma', a, b, c), '!options->lower_ffma'),
103 # Comparison simplifications
104 (('~inot', ('flt', a, b)), ('fge', a, b)),
105 (('~inot', ('fge', a, b)), ('flt', a, b)),
106 (('~inot', ('feq', a, b)), ('fne', a, b)),
107 (('~inot', ('fne', a, b)), ('feq', a, b)),
108 (('inot', ('ilt', a, b)), ('ige', a, b)),
109 (('inot', ('ige', a, b)), ('ilt', a, b)),
110 (('inot', ('ieq', a, b)), ('ine', a, b)),
111 (('inot', ('ine', a, b)), ('ieq', a, b)),
112
113 # 0.0 >= b2f(a)
114 # b2f(a) <= 0.0
115 # b2f(a) == 0.0 because b2f(a) can only be 0 or 1
116 # inot(a)
117 (('fge', 0.0, ('b2f', a)), ('inot', a)),
118
119 # 0.0 < fabs(a)
120 # fabs(a) > 0.0
121 # fabs(a) != 0.0 because fabs(a) must be >= 0
122 # a != 0.0
123 (('flt', 0.0, ('fabs', a)), ('fne', a, 0.0)),
124
125 (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
126 (('bcsel', ('flt', b, a), b, a), ('fmin', a, b)),
127 (('bcsel', ('flt', a, b), b, a), ('fmax', a, b)),
128 (('bcsel', ('inot', 'a@bool'), b, c), ('bcsel', a, c, b)),
129 (('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)),
130 (('bcsel', a, True, 'b@bool'), ('ior', a, b)),
131 (('fmin', a, a), a),
132 (('fmax', a, a), a),
133 (('imin', a, a), a),
134 (('imax', a, a), a),
135 (('umin', a, a), a),
136 (('umax', a, a), a),
137 (('~fmin', ('fmax', a, 0.0), 1.0), ('fsat', a), '!options->lower_fsat'),
138 (('~fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
139 (('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
140 (('fsat', ('fsat', a)), ('fsat', a)),
141 (('fmin', ('fmax', ('fmin', ('fmax', a, b), c), b), c), ('fmin', ('fmax', a, b), c)),
142 (('imin', ('imax', ('imin', ('imax', a, b), c), b), c), ('imin', ('imax', a, b), c)),
143 (('umin', ('umax', ('umin', ('umax', a, b), c), b), c), ('umin', ('umax', a, b), c)),
144 (('extract_u8', ('imin', ('imax', a, 0), 0xff), 0), ('imin', ('imax', a, 0), 0xff)),
145 (('~ior', ('flt', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
146 (('~ior', ('flt', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
147 (('~ior', ('fge', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
148 (('~ior', ('fge', a, c), ('fge', b, c)), ('fge', ('fmax', a, b), c)),
149 (('fabs', ('slt', a, b)), ('slt', a, b)),
150 (('fabs', ('sge', a, b)), ('sge', a, b)),
151 (('fabs', ('seq', a, b)), ('seq', a, b)),
152 (('fabs', ('sne', a, b)), ('sne', a, b)),
153 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
154 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
155 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
156 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
157 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
158 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
159 # Emulating booleans
160 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
161 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
162 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
163 (('iand', 'a@bool', 1.0), ('b2f', a)),
164 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
165 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
166 # Comparison with the same args. Note that these are not done for
167 # the float versions because NaN always returns false on float
168 # inequalities.
169 (('ilt', a, a), False),
170 (('ige', a, a), True),
171 (('ieq', a, a), True),
172 (('ine', a, a), False),
173 (('ult', a, a), False),
174 (('uge', a, a), True),
175 # Logical and bit operations
176 (('fand', a, 0.0), 0.0),
177 (('iand', a, a), a),
178 (('iand', a, ~0), a),
179 (('iand', a, 0), 0),
180 (('ior', a, a), a),
181 (('ior', a, 0), a),
182 (('fxor', a, a), 0.0),
183 (('ixor', a, a), 0),
184 (('ixor', a, 0), a),
185 (('inot', ('inot', a)), a),
186 # DeMorgan's Laws
187 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
188 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
189 # Shift optimizations
190 (('ishl', 0, a), 0),
191 (('ishl', a, 0), a),
192 (('ishr', 0, a), 0),
193 (('ishr', a, 0), a),
194 (('ushr', 0, a), 0),
195 (('ushr', a, 0), a),
196 (('iand', 0xff, ('ushr', a, 24)), ('ushr', a, 24)),
197 (('iand', 0xffff, ('ushr', a, 16)), ('ushr', a, 16)),
198 # Exponential/logarithmic identities
199 (('~fexp2', ('flog2', a)), a), # 2^lg2(a) = a
200 (('~flog2', ('fexp2', a)), a), # lg2(2^a) = a
201 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
202 (('~fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
203 (('~fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
204 ('~fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
205 (('~fpow', a, 1.0), a),
206 (('~fpow', a, 2.0), ('fmul', a, a)),
207 (('~fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
208 (('~fpow', 2.0, a), ('fexp2', a)),
209 (('~fpow', ('fpow', a, 2.2), 0.454545), a),
210 (('~fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
211 (('~fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
212 (('~frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
213 (('~frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
214 (('~flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
215 (('~flog2', ('frcp', a)), ('fneg', ('flog2', a))),
216 (('~flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
217 (('~flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
218 (('~fadd', ('flog2', a), ('flog2', b)), ('flog2', ('fmul', a, b))),
219 (('~fadd', ('flog2', a), ('fneg', ('flog2', b))), ('flog2', ('fdiv', a, b))),
220 (('~fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
221 # Division and reciprocal
222 (('~fdiv', 1.0, a), ('frcp', a)),
223 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
224 (('~frcp', ('frcp', a)), a),
225 (('~frcp', ('fsqrt', a)), ('frsq', a)),
226 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
227 (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
228 # Boolean simplifications
229 (('ieq', 'a@bool', True), a),
230 (('ine', 'a@bool', True), ('inot', a)),
231 (('ine', 'a@bool', False), a),
232 (('ieq', 'a@bool', False), ('inot', 'a')),
233 (('bcsel', a, True, False), ('ine', a, 0)),
234 (('bcsel', a, False, True), ('ieq', a, 0)),
235 (('bcsel', True, b, c), b),
236 (('bcsel', False, b, c), c),
237 # The result of this should be hit by constant propagation and, in the
238 # next round of opt_algebraic, get picked up by one of the above two.
239 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
240
241 (('bcsel', a, b, b), b),
242 (('fcsel', a, b, b), b),
243
244 # Conversions
245 (('i2b', ('b2i', a)), a),
246 (('f2i', ('ftrunc', a)), ('f2i', a)),
247 (('f2u', ('ftrunc', a)), ('f2u', a)),
248 (('i2b', ('ineg', a)), ('i2b', a)),
249 (('i2b', ('iabs', a)), ('i2b', a)),
250 (('fabs', ('b2f', a)), ('b2f', a)),
251 (('iabs', ('b2i', a)), ('b2i', a)),
252
253 # Byte extraction
254 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
255 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
256 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
257 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
258
259 # Word extraction
260 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
261 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
262
263 # Subtracts
264 (('~fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
265 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
266 (('ussub_4x8', a, 0), a),
267 (('ussub_4x8', a, ~0), 0),
268 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
269 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
270 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
271 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
272 (('~fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
273 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
274 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
275 (('iabs', ('isub', 0, a)), ('iabs', a)),
276
277 # Propagate negation up multiplication chains
278 (('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
279 (('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
280
281 # Reassociate constants in add/mul chains so they can be folded together.
282 # For now, we only handle cases where the constants are separated by
283 # a single non-constant. We could do better eventually.
284 (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
285 (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
286 (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
287 (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
288
289 # Misc. lowering
290 (('fmod', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod'),
291 (('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod'),
292 (('uadd_carry', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
293 (('usub_borrow', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
294
295 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
296 ('bcsel', ('ilt', 31, 'bits'), 'insert',
297 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
298 'options->lower_bitfield_insert'),
299
300 (('ibitfield_extract', 'value', 'offset', 'bits'),
301 ('bcsel', ('ilt', 31, 'bits'), 'value',
302 ('ibfe', 'value', 'offset', 'bits')),
303 'options->lower_bitfield_extract'),
304
305 (('ubitfield_extract', 'value', 'offset', 'bits'),
306 ('bcsel', ('ult', 31, 'bits'), 'value',
307 ('ubfe', 'value', 'offset', 'bits')),
308 'options->lower_bitfield_extract'),
309
310 (('extract_i8', a, b),
311 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
312 'options->lower_extract_byte'),
313
314 (('extract_u8', a, b),
315 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
316 'options->lower_extract_byte'),
317
318 (('extract_i16', a, b),
319 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
320 'options->lower_extract_word'),
321
322 (('extract_u16', a, b),
323 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
324 'options->lower_extract_word'),
325
326 (('pack_unorm_2x16', 'v'),
327 ('pack_uvec2_to_uint',
328 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
329 'options->lower_pack_unorm_2x16'),
330
331 (('pack_unorm_4x8', 'v'),
332 ('pack_uvec4_to_uint',
333 ('f2u', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
334 'options->lower_pack_unorm_4x8'),
335
336 (('pack_snorm_2x16', 'v'),
337 ('pack_uvec2_to_uint',
338 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
339 'options->lower_pack_snorm_2x16'),
340
341 (('pack_snorm_4x8', 'v'),
342 ('pack_uvec4_to_uint',
343 ('f2i', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
344 'options->lower_pack_snorm_4x8'),
345
346 (('unpack_unorm_2x16', 'v'),
347 ('fdiv', ('u2f', ('vec2', ('extract_u16', 'v', 0),
348 ('extract_u16', 'v', 1))),
349 65535.0),
350 'options->lower_unpack_unorm_2x16'),
351
352 (('unpack_unorm_4x8', 'v'),
353 ('fdiv', ('u2f', ('vec4', ('extract_u8', 'v', 0),
354 ('extract_u8', 'v', 1),
355 ('extract_u8', 'v', 2),
356 ('extract_u8', 'v', 3))),
357 255.0),
358 'options->lower_unpack_unorm_4x8'),
359
360 (('unpack_snorm_2x16', 'v'),
361 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec2', ('extract_i16', 'v', 0),
362 ('extract_i16', 'v', 1))),
363 32767.0))),
364 'options->lower_unpack_snorm_2x16'),
365
366 (('unpack_snorm_4x8', 'v'),
367 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f', ('vec4', ('extract_i8', 'v', 0),
368 ('extract_i8', 'v', 1),
369 ('extract_i8', 'v', 2),
370 ('extract_i8', 'v', 3))),
371 127.0))),
372 'options->lower_unpack_snorm_4x8'),
373 ]
374
375 def fexp2i(exp):
376 # We assume that exp is already in the range [-126, 127].
377 return ('ishl', ('iadd', exp, 127), 23)
378
379 def ldexp32(f, exp):
380 # First, we clamp exp to a reasonable range. The maximum possible range
381 # for a normal exponent is [-126, 127] and, throwing in denormals, you get
382 # a maximum range of [-149, 127]. This means that we can potentially have
383 # a swing of +-276. If you start with FLT_MAX, you actually have to do
384 # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
385 # spec, on the other hand, only requires that we handle an exponent value
386 # in the range [-126, 128]. This implementation is *mostly* correct; it
387 # handles a range on exp of [-252, 254] which allows you to create any
388 # value (including denorms if the hardware supports it) and to adjust the
389 # exponent of any normal value to anything you want.
390 exp = ('imin', ('imax', exp, -252), 254)
391
392 # Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
393 # (We use ishr which isn't the same for -1, but the -1 case still works
394 # since we use exp-exp/2 as the second exponent.) While the spec
395 # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
396 # work with denormals and doesn't allow for the full swing in exponents
397 # that you can get with normalized values. Instead, we create two powers
398 # of two and multiply by them each in turn. That way the effective range
399 # of our exponent is doubled.
400 pow2_1 = fexp2i(('ishr', exp, 1))
401 pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)))
402 return ('fmul', ('fmul', f, pow2_1), pow2_2)
403
404 optimizations += [(('ldexp', 'x', 'exp'), ldexp32('x', 'exp'))]
405
406 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
407 def bitfield_reverse(u):
408 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
409 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
410 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
411 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
412 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
413
414 return step5
415
416 optimizations += [(bitfield_reverse('x'), ('bitfield_reverse', 'x'))]
417
418
419 # Add optimizations to handle the case where the result of a ternary is
420 # compared to a constant. This way we can take things like
421 #
422 # (a ? 0 : 1) > 0
423 #
424 # and turn it into
425 #
426 # a ? (0 > 0) : (1 > 0)
427 #
428 # which constant folding will eat for lunch. The resulting ternary will
429 # further get cleaned up by the boolean reductions above and we will be
430 # left with just the original variable "a".
431 for op in ['flt', 'fge', 'feq', 'fne',
432 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
433 optimizations += [
434 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
435 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
436 ((op, '#d', ('bcsel', a, '#b', '#c')),
437 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
438 ]
439
440 # This section contains "late" optimizations that should be run after the
441 # regular optimizations have finished. Optimizations should go here if
442 # they help code generation but do not necessarily produce code that is
443 # more easily optimizable.
444 late_optimizations = [
445 # Most of these optimizations aren't quite safe when you get infinity or
446 # Nan involved but the first one should be fine.
447 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
448 (('~fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
449 (('~feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
450 (('~fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
451
452 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
453 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
454 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
455 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
456 ]
457
458 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
459 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
460 late_optimizations).render()