nir: Replace an odd comparison involving fmin of -b2f
[mesa.git] / src / compiler / nir / nir_opt_algebraic.py
1 #
2 # Copyright (C) 2014 Intel Corporation
3 #
4 # Permission is hereby granted, free of charge, to any person obtaining a
5 # copy of this software and associated documentation files (the "Software"),
6 # to deal in the Software without restriction, including without limitation
7 # the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 # and/or sell copies of the Software, and to permit persons to whom the
9 # Software is furnished to do so, subject to the following conditions:
10 #
11 # The above copyright notice and this permission notice (including the next
12 # paragraph) shall be included in all copies or substantial portions of the
13 # Software.
14 #
15 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 # IN THE SOFTWARE.
22 #
23 # Authors:
24 # Jason Ekstrand (jason@jlekstrand.net)
25
26 import nir_algebraic
27
28 # Convenience variables
29 a = 'a'
30 b = 'b'
31 c = 'c'
32 d = 'd'
33
34 # Written in the form (<search>, <replace>) where <search> is an expression
35 # and <replace> is either an expression or a value. An expression is
36 # defined as a tuple of the form ([~]<op>, <src0>, <src1>, <src2>, <src3>)
37 # where each source is either an expression or a value. A value can be
38 # either a numeric constant or a string representing a variable name.
39 #
40 # If the opcode in a search expression is prefixed by a '~' character, this
41 # indicates that the operation is inexact. Such operations will only get
42 # applied to SSA values that do not have the exact bit set. This should be
43 # used by by any optimizations that are not bit-for-bit exact. It should not,
44 # however, be used for backend-requested lowering operations as those need to
45 # happen regardless of precision.
46 #
47 # Variable names are specified as "[#]name[@type][(cond)]" where "#" inicates
48 # that the given variable will only match constants and the type indicates that
49 # the given variable will only match values from ALU instructions with the
50 # given output type, and (cond) specifies an additional condition function
51 # (see nir_search_helpers.h).
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 # All expression types can have a bit-size specified. For opcodes, this
58 # looks like "op@32", for variables it is "a@32" or "a@uint32" to specify a
59 # type and size, and for literals, you can write "2.0@32". In the search half
60 # of the expression this indicates that it should only match that particular
61 # bit-size. In the replace half of the expression this indicates that the
62 # constructed value should have that bit-size.
63
64 optimizations = [
65
66 (('imul', a, '#b@32(is_pos_power_of_two)'), ('ishl', a, ('find_lsb', b))),
67 (('imul', a, '#b@32(is_neg_power_of_two)'), ('ineg', ('ishl', a, ('find_lsb', ('iabs', b))))),
68 (('udiv', a, 1), a),
69 (('idiv', a, 1), a),
70 (('umod', a, 1), 0),
71 (('imod', a, 1), 0),
72 (('udiv', a, '#b@32(is_pos_power_of_two)'), ('ushr', a, ('find_lsb', b))),
73 (('idiv', a, '#b@32(is_pos_power_of_two)'), ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', b))), 'options->lower_idiv'),
74 (('idiv', a, '#b@32(is_neg_power_of_two)'), ('ineg', ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', ('iabs', b))))), 'options->lower_idiv'),
75 (('umod', a, '#b(is_pos_power_of_two)'), ('iand', a, ('isub', b, 1))),
76
77 (('fneg', ('fneg', a)), a),
78 (('ineg', ('ineg', a)), a),
79 (('fabs', ('fabs', a)), ('fabs', a)),
80 (('fabs', ('fneg', a)), ('fabs', a)),
81 (('fabs', ('u2f32', a)), ('u2f32', a)),
82 (('iabs', ('iabs', a)), ('iabs', a)),
83 (('iabs', ('ineg', a)), ('iabs', a)),
84 (('~fadd', a, 0.0), a),
85 (('iadd', a, 0), a),
86 (('usadd_4x8', a, 0), a),
87 (('usadd_4x8', a, ~0), ~0),
88 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
89 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
90 (('~fadd', ('fneg', a), a), 0.0),
91 (('iadd', ('ineg', a), a), 0),
92 (('iadd', ('ineg', a), ('iadd', a, b)), b),
93 (('iadd', a, ('iadd', ('ineg', a), b)), b),
94 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
95 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
96 (('~fmul', a, 0.0), 0.0),
97 (('imul', a, 0), 0),
98 (('umul_unorm_4x8', a, 0), 0),
99 (('umul_unorm_4x8', a, ~0), a),
100 (('fmul', a, 1.0), a),
101 (('imul', a, 1), a),
102 (('fmul', a, -1.0), ('fneg', a)),
103 (('imul', a, -1), ('ineg', a)),
104 (('~ffma', 0.0, a, b), b),
105 (('~ffma', a, 0.0, b), b),
106 (('~ffma', a, b, 0.0), ('fmul', a, b)),
107 (('ffma', a, 1.0, b), ('fadd', a, b)),
108 (('ffma', 1.0, a, b), ('fadd', a, b)),
109 (('~flrp', a, b, 0.0), a),
110 (('~flrp', a, b, 1.0), b),
111 (('~flrp', a, a, b), a),
112 (('~flrp', 0.0, a, b), ('fmul', a, b)),
113 (('~flrp', a, b, ('b2f', c)), ('bcsel', c, b, a), 'options->lower_flrp32'),
114 (('~flrp', a, 0.0, c), ('fadd', ('fmul', ('fneg', a), c), a)),
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 # fmin(-b2f(a), b) >= 0.0
156 # -b2f(a) >= 0.0 && b >= 0.0
157 # -b2f(a) == 0.0 && b >= 0.0 -b2f can only be 0 or -1, never >0
158 # b2f(a) == 0.0 && b >= 0.0
159 # a == False && b >= 0.0
160 # !a && b >= 0.0
161 #
162 # The fge in the second replacement is not a typo. I leave the proof that
163 # "fmin(-b2f(a), b) >= 0 <=> fmin(-b2f(a), b) == 0" as an exercise for the
164 # reader.
165 (('fge', ('fmin', ('fneg', ('b2f', a)), b), 0.0), ('iand', ('inot', a), ('fge', b, 0.0))),
166 (('feq', ('fmin', ('fneg', ('b2f', a)), b), 0.0), ('iand', ('inot', a), ('fge', b, 0.0))),
167
168 # 0.0 < fabs(a)
169 # fabs(a) > 0.0
170 # fabs(a) != 0.0 because fabs(a) must be >= 0
171 # a != 0.0
172 (('flt', 0.0, ('fabs', a)), ('fne', a, 0.0)),
173
174 (('fmax', ('b2f(is_used_once)', a), ('b2f', b)), ('b2f', ('ior', a, b))),
175 (('fmax', ('fneg(is_used_once)', ('b2f(is_used_once)', a)), ('fneg', ('b2f', b))), ('fneg', ('b2f', ('ior', a, b)))),
176 (('fmin', ('b2f(is_used_once)', a), ('b2f', b)), ('b2f', ('iand', a, b))),
177 (('fmin', ('fneg(is_used_once)', ('b2f(is_used_once)', a)), ('fneg', ('b2f', b))), ('fneg', ('b2f', ('iand', a, b)))),
178
179 # ignore this opt when the result is used by a bcsel or if so we can make
180 # use of conditional modifiers on supported hardware.
181 (('flt(is_not_used_by_conditional)', ('fadd(is_used_once)', a, ('fneg', b)), 0.0), ('flt', a, b)),
182
183 (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
184 (('~bcsel', ('flt', b, a), b, a), ('fmin', a, b)),
185 (('~bcsel', ('flt', a, b), b, a), ('fmax', a, b)),
186 (('~bcsel', ('fge', a, b), b, a), ('fmin', a, b)),
187 (('~bcsel', ('fge', b, a), b, a), ('fmax', a, b)),
188 (('bcsel', ('inot', a), b, c), ('bcsel', a, c, b)),
189 (('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)),
190 (('bcsel', a, True, 'b@bool'), ('ior', a, b)),
191 (('fmin', a, a), a),
192 (('fmax', a, a), a),
193 (('imin', a, a), a),
194 (('imax', a, a), a),
195 (('umin', a, a), a),
196 (('umax', a, a), a),
197 (('fmin', a, ('fneg', a)), ('fneg', ('fabs', a))),
198 (('imin', a, ('ineg', a)), ('ineg', ('iabs', a))),
199 (('fmin', a, ('fneg', ('fabs', a))), ('fneg', ('fabs', a))),
200 (('imin', a, ('ineg', ('iabs', a))), ('ineg', ('iabs', a))),
201 (('fmin', a, ('fabs', a)), a),
202 (('imin', a, ('iabs', a)), a),
203 (('fmax', a, ('fneg', ('fabs', a))), a),
204 (('imax', a, ('ineg', ('iabs', a))), a),
205 (('fmax', a, ('fabs', a)), ('fabs', a)),
206 (('imax', a, ('iabs', a)), ('iabs', a)),
207 (('fmax', a, ('fneg', a)), ('fabs', a)),
208 (('imax', a, ('ineg', a)), ('iabs', a)),
209 (('~fmin', ('fmax', a, 0.0), 1.0), ('fsat', a), '!options->lower_fsat'),
210 (('~fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
211 (('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
212 (('fsat', ('fsat', a)), ('fsat', a)),
213 (('fmin', ('fmax', ('fmin', ('fmax', a, b), c), b), c), ('fmin', ('fmax', a, b), c)),
214 (('imin', ('imax', ('imin', ('imax', a, b), c), b), c), ('imin', ('imax', a, b), c)),
215 (('umin', ('umax', ('umin', ('umax', a, b), c), b), c), ('umin', ('umax', a, b), c)),
216 (('fmax', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmax', a, b))),
217 (('fmin', ('fsat', a), '#b@32(is_zero_to_one)'), ('fsat', ('fmin', a, b))),
218 (('extract_u8', ('imin', ('imax', a, 0), 0xff), 0), ('imin', ('imax', a, 0), 0xff)),
219 (('~ior', ('flt(is_used_once)', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
220 (('~ior', ('flt(is_used_once)', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
221 (('~ior', ('fge(is_used_once)', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
222 (('~ior', ('fge(is_used_once)', a, c), ('fge', b, c)), ('fge', ('fmax', a, b), c)),
223 (('~ior', ('flt', a, '#b'), ('flt', a, '#c')), ('flt', a, ('fmax', b, c))),
224 (('~ior', ('flt', '#a', c), ('flt', '#b', c)), ('flt', ('fmin', a, b), c)),
225 (('~ior', ('fge', a, '#b'), ('fge', a, '#c')), ('fge', a, ('fmin', b, c))),
226 (('~ior', ('fge', '#a', c), ('fge', '#b', c)), ('fge', ('fmax', a, b), c)),
227 (('~iand', ('flt(is_used_once)', a, b), ('flt', a, c)), ('flt', a, ('fmin', b, c))),
228 (('~iand', ('flt(is_used_once)', a, c), ('flt', b, c)), ('flt', ('fmax', a, b), c)),
229 (('~iand', ('fge(is_used_once)', a, b), ('fge', a, c)), ('fge', a, ('fmax', b, c))),
230 (('~iand', ('fge(is_used_once)', a, c), ('fge', b, c)), ('fge', ('fmin', a, b), c)),
231 (('~iand', ('flt', a, '#b'), ('flt', a, '#c')), ('flt', a, ('fmin', b, c))),
232 (('~iand', ('flt', '#a', c), ('flt', '#b', c)), ('flt', ('fmax', a, b), c)),
233 (('~iand', ('fge', a, '#b'), ('fge', a, '#c')), ('fge', a, ('fmax', b, c))),
234 (('~iand', ('fge', '#a', c), ('fge', '#b', c)), ('fge', ('fmin', a, b), c)),
235
236 (('ior', ('ilt(is_used_once)', a, b), ('ilt', a, c)), ('ilt', a, ('imax', b, c))),
237 (('ior', ('ilt(is_used_once)', a, c), ('ilt', b, c)), ('ilt', ('imin', a, b), c)),
238 (('ior', ('ige(is_used_once)', a, b), ('ige', a, c)), ('ige', a, ('imin', b, c))),
239 (('ior', ('ige(is_used_once)', a, c), ('ige', b, c)), ('ige', ('imax', a, b), c)),
240 (('ior', ('ult(is_used_once)', a, b), ('ult', a, c)), ('ult', a, ('umax', b, c))),
241 (('ior', ('ult(is_used_once)', a, c), ('ult', b, c)), ('ult', ('umin', a, b), c)),
242 (('ior', ('uge(is_used_once)', a, b), ('uge', a, c)), ('uge', a, ('umin', b, c))),
243 (('ior', ('uge(is_used_once)', a, c), ('uge', b, c)), ('uge', ('umax', a, b), c)),
244 (('iand', ('ilt(is_used_once)', a, b), ('ilt', a, c)), ('ilt', a, ('imin', b, c))),
245 (('iand', ('ilt(is_used_once)', a, c), ('ilt', b, c)), ('ilt', ('imax', a, b), c)),
246 (('iand', ('ige(is_used_once)', a, b), ('ige', a, c)), ('ige', a, ('imax', b, c))),
247 (('iand', ('ige(is_used_once)', a, c), ('ige', b, c)), ('ige', ('imin', a, b), c)),
248 (('iand', ('ult(is_used_once)', a, b), ('ult', a, c)), ('ult', a, ('umin', b, c))),
249 (('iand', ('ult(is_used_once)', a, c), ('ult', b, c)), ('ult', ('umax', a, b), c)),
250 (('iand', ('uge(is_used_once)', a, b), ('uge', a, c)), ('uge', a, ('umax', b, c))),
251 (('iand', ('uge(is_used_once)', a, c), ('uge', b, c)), ('uge', ('umin', a, b), c)),
252
253 # These patterns can result when (a < b || a < c) => (a < min(b, c))
254 # transformations occur before constant propagation and loop-unrolling.
255 (('~flt', a, ('fmax', b, a)), ('flt', a, b)),
256 (('~flt', ('fmin', a, b), a), ('flt', b, a)),
257 (('~fge', a, ('fmin', b, a)), True),
258 (('~fge', ('fmax', a, b), a), True),
259 (('~flt', a, ('fmin', b, a)), False),
260 (('~flt', ('fmax', a, b), a), False),
261
262 (('ilt', a, ('imax', b, a)), ('ilt', a, b)),
263 (('ilt', ('imin', a, b), a), ('ilt', b, a)),
264 (('ige', a, ('imin', b, a)), True),
265 (('ige', ('imax', a, b), a), True),
266 (('ult', a, ('umax', b, a)), ('ult', a, b)),
267 (('ult', ('umin', a, b), a), ('ult', b, a)),
268 (('uge', a, ('umin', b, a)), True),
269 (('uge', ('umax', a, b), a), True),
270
271 (('ilt', '#a', ('imin', '#b', c)), ('iand', ('ilt', a, b), ('ilt', a, c))),
272 (('ilt', ('imax', '#a', b), '#c'), ('iand', ('ilt', a, c), ('ilt', b, c))),
273 (('ige', '#a', ('imax', '#b', c)), ('iand', ('ige', a, b), ('ige', a, c))),
274 (('ige', ('imin', '#a', b), '#c'), ('iand', ('ige', a, c), ('ige', b, c))),
275 (('ult', '#a', ('umin', '#b', c)), ('iand', ('ult', a, b), ('ult', a, c))),
276 (('ult', ('umax', '#a', b), '#c'), ('iand', ('ult', a, c), ('ult', b, c))),
277 (('uge', '#a', ('umax', '#b', c)), ('iand', ('uge', a, b), ('uge', a, c))),
278 (('uge', ('umin', '#a', b), '#c'), ('iand', ('uge', a, c), ('uge', b, c))),
279
280 (('fabs', ('slt', a, b)), ('slt', a, b)),
281 (('fabs', ('sge', a, b)), ('sge', a, b)),
282 (('fabs', ('seq', a, b)), ('seq', a, b)),
283 (('fabs', ('sne', a, b)), ('sne', a, b)),
284 (('slt', a, b), ('b2f', ('flt', a, b)), 'options->lower_scmp'),
285 (('sge', a, b), ('b2f', ('fge', a, b)), 'options->lower_scmp'),
286 (('seq', a, b), ('b2f', ('feq', a, b)), 'options->lower_scmp'),
287 (('sne', a, b), ('b2f', ('fne', a, b)), 'options->lower_scmp'),
288 (('fne', ('fneg', a), a), ('fne', a, 0.0)),
289 (('feq', ('fneg', a), a), ('feq', a, 0.0)),
290 # Emulating booleans
291 (('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
292 (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
293 (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
294 (('iand', 'a@bool', 1.0), ('b2f', a)),
295 # True/False are ~0 and 0 in NIR. b2i of True is 1, and -1 is ~0 (True).
296 (('ineg', ('b2i@32', a)), a),
297 (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
298 (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
299 # Comparison with the same args. Note that these are not done for
300 # the float versions because NaN always returns false on float
301 # inequalities.
302 (('ilt', a, a), False),
303 (('ige', a, a), True),
304 (('ieq', a, a), True),
305 (('ine', a, a), False),
306 (('ult', a, a), False),
307 (('uge', a, a), True),
308 # Logical and bit operations
309 (('fand', a, 0.0), 0.0),
310 (('iand', a, a), a),
311 (('iand', a, ~0), a),
312 (('iand', a, 0), 0),
313 (('ior', a, a), a),
314 (('ior', a, 0), a),
315 (('ior', a, True), True),
316 (('fxor', a, a), 0.0),
317 (('ixor', a, a), 0),
318 (('ixor', a, 0), a),
319 (('inot', ('inot', a)), a),
320 # DeMorgan's Laws
321 (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))),
322 (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))),
323 # Shift optimizations
324 (('ishl', 0, a), 0),
325 (('ishl', a, 0), a),
326 (('ishr', 0, a), 0),
327 (('ishr', a, 0), a),
328 (('ushr', 0, a), 0),
329 (('ushr', a, 0), a),
330 (('iand', 0xff, ('ushr@32', a, 24)), ('ushr', a, 24)),
331 (('iand', 0xffff, ('ushr@32', a, 16)), ('ushr', a, 16)),
332 # Exponential/logarithmic identities
333 (('~fexp2', ('flog2', a)), a), # 2^lg2(a) = a
334 (('~flog2', ('fexp2', a)), a), # lg2(2^a) = a
335 (('fpow', a, b), ('fexp2', ('fmul', ('flog2', a), b)), 'options->lower_fpow'), # a^b = 2^(lg2(a)*b)
336 (('~fexp2', ('fmul', ('flog2', a), b)), ('fpow', a, b), '!options->lower_fpow'), # 2^(lg2(a)*b) = a^b
337 (('~fexp2', ('fadd', ('fmul', ('flog2', a), b), ('fmul', ('flog2', c), d))),
338 ('~fmul', ('fpow', a, b), ('fpow', c, d)), '!options->lower_fpow'), # 2^(lg2(a) * b + lg2(c) + d) = a^b * c^d
339 (('~fexp2', ('fmul', ('flog2', a), 2.0)), ('fmul', a, a)),
340 (('~fexp2', ('fmul', ('flog2', a), 4.0)), ('fmul', ('fmul', a, a), ('fmul', a, a))),
341 (('~fpow', a, 1.0), a),
342 (('~fpow', a, 2.0), ('fmul', a, a)),
343 (('~fpow', a, 4.0), ('fmul', ('fmul', a, a), ('fmul', a, a))),
344 (('~fpow', 2.0, a), ('fexp2', a)),
345 (('~fpow', ('fpow', a, 2.2), 0.454545), a),
346 (('~fpow', ('fabs', ('fpow', a, 2.2)), 0.454545), ('fabs', a)),
347 (('~fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
348 (('~frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
349 (('~frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
350 (('~flog2', ('fsqrt', a)), ('fmul', 0.5, ('flog2', a))),
351 (('~flog2', ('frcp', a)), ('fneg', ('flog2', a))),
352 (('~flog2', ('frsq', a)), ('fmul', -0.5, ('flog2', a))),
353 (('~flog2', ('fpow', a, b)), ('fmul', b, ('flog2', a))),
354 (('~fmul', ('fexp2(is_used_once)', a), ('fexp2(is_used_once)', b)), ('fexp2', ('fadd', a, b))),
355 # Division and reciprocal
356 (('~fdiv', 1.0, a), ('frcp', a)),
357 (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
358 (('~frcp', ('frcp', a)), a),
359 (('~frcp', ('fsqrt', a)), ('frsq', a)),
360 (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
361 (('~frcp', ('frsq', a)), ('fsqrt', a), '!options->lower_fsqrt'),
362 # Boolean simplifications
363 (('ieq', 'a@bool', True), a),
364 (('ine(is_not_used_by_if)', 'a@bool', True), ('inot', a)),
365 (('ine', 'a@bool', False), a),
366 (('ieq(is_not_used_by_if)', 'a@bool', False), ('inot', 'a')),
367 (('bcsel', a, True, False), a),
368 (('bcsel', a, False, True), ('inot', a)),
369 (('bcsel@32', a, 1.0, 0.0), ('b2f', a)),
370 (('bcsel@32', a, 0.0, 1.0), ('b2f', ('inot', a))),
371 (('bcsel@32', a, -1.0, -0.0), ('fneg', ('b2f', a))),
372 (('bcsel@32', a, -0.0, -1.0), ('fneg', ('b2f', ('inot', a)))),
373 (('bcsel', True, b, c), b),
374 (('bcsel', False, b, c), c),
375 # The result of this should be hit by constant propagation and, in the
376 # next round of opt_algebraic, get picked up by one of the above two.
377 (('bcsel', '#a', b, c), ('bcsel', ('ine', 'a', 0), b, c)),
378
379 (('bcsel', a, b, b), b),
380 (('fcsel', a, b, b), b),
381
382 # Conversions
383 (('i2b', ('b2i', a)), a),
384 (('f2i32', ('ftrunc', a)), ('f2i32', a)),
385 (('f2u32', ('ftrunc', a)), ('f2u32', a)),
386 (('i2b', ('ineg', a)), ('i2b', a)),
387 (('i2b', ('iabs', a)), ('i2b', a)),
388 (('fabs', ('b2f', a)), ('b2f', a)),
389 (('iabs', ('b2i', a)), ('b2i', a)),
390
391 # Packing and then unpacking does nothing
392 (('unpack_64_2x32_split_x', ('pack_64_2x32_split', a, b)), a),
393 (('unpack_64_2x32_split_y', ('pack_64_2x32_split', a, b)), b),
394 (('pack_64_2x32_split', ('unpack_64_2x32_split_x', a),
395 ('unpack_64_2x32_split_y', a)), a),
396
397 # Byte extraction
398 (('ushr', a, 24), ('extract_u8', a, 3), '!options->lower_extract_byte'),
399 (('iand', 0xff, ('ushr', a, 16)), ('extract_u8', a, 2), '!options->lower_extract_byte'),
400 (('iand', 0xff, ('ushr', a, 8)), ('extract_u8', a, 1), '!options->lower_extract_byte'),
401 (('iand', 0xff, a), ('extract_u8', a, 0), '!options->lower_extract_byte'),
402
403 # Word extraction
404 (('ushr', a, 16), ('extract_u16', a, 1), '!options->lower_extract_word'),
405 (('iand', 0xffff, a), ('extract_u16', a, 0), '!options->lower_extract_word'),
406
407 # Subtracts
408 (('~fsub', a, ('fsub', 0.0, b)), ('fadd', a, b)),
409 (('isub', a, ('isub', 0, b)), ('iadd', a, b)),
410 (('ussub_4x8', a, 0), a),
411 (('ussub_4x8', a, ~0), 0),
412 (('fsub', a, b), ('fadd', a, ('fneg', b)), 'options->lower_sub'),
413 (('isub', a, b), ('iadd', a, ('ineg', b)), 'options->lower_sub'),
414 (('fneg', a), ('fsub', 0.0, a), 'options->lower_negate'),
415 (('ineg', a), ('isub', 0, a), 'options->lower_negate'),
416 (('~fadd', a, ('fsub', 0.0, b)), ('fsub', a, b)),
417 (('iadd', a, ('isub', 0, b)), ('isub', a, b)),
418 (('fabs', ('fsub', 0.0, a)), ('fabs', a)),
419 (('iabs', ('isub', 0, a)), ('iabs', a)),
420
421 # Propagate negation up multiplication chains
422 (('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
423 (('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
424
425 # Propagate constants up multiplication chains
426 (('~fmul(is_used_once)', ('fmul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fmul', ('fmul', a, c), b)),
427 (('imul(is_used_once)', ('imul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('imul', ('imul', a, c), b)),
428 (('~fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fadd', ('fadd', a, c), b)),
429 (('iadd(is_used_once)', ('iadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('iadd', ('iadd', a, c), b)),
430
431 # Reassociate constants in add/mul chains so they can be folded together.
432 # For now, we mostly only handle cases where the constants are separated by
433 # a single non-constant. We could do better eventually.
434 (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
435 (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
436 (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
437 (('~fadd', '#a', ('fneg', ('fadd', b, '#c'))), ('fadd', ('fadd', a, ('fneg', c)), ('fneg', b))),
438 (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
439
440 # By definition...
441 (('bcsel', ('ige', ('find_lsb', a), 0), ('find_lsb', a), -1), ('find_lsb', a)),
442 (('bcsel', ('ige', ('ifind_msb', a), 0), ('ifind_msb', a), -1), ('ifind_msb', a)),
443 (('bcsel', ('ige', ('ufind_msb', a), 0), ('ufind_msb', a), -1), ('ufind_msb', a)),
444
445 (('bcsel', ('ine', a, 0), ('find_lsb', a), -1), ('find_lsb', a)),
446 (('bcsel', ('ine', a, 0), ('ifind_msb', a), -1), ('ifind_msb', a)),
447 (('bcsel', ('ine', a, 0), ('ufind_msb', a), -1), ('ufind_msb', a)),
448
449 (('bcsel', ('ine', a, -1), ('ifind_msb', a), -1), ('ifind_msb', a)),
450
451 # Misc. lowering
452 (('fmod@32', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod32'),
453 (('fmod@64', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod64'),
454 (('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod32'),
455 (('uadd_carry@32', a, b), ('b2i', ('ult', ('iadd', a, b), a)), 'options->lower_uadd_carry'),
456 (('usub_borrow@32', a, b), ('b2i', ('ult', a, b)), 'options->lower_usub_borrow'),
457
458 (('bitfield_insert', 'base', 'insert', 'offset', 'bits'),
459 ('bcsel', ('ilt', 31, 'bits'), 'insert',
460 ('bfi', ('bfm', 'bits', 'offset'), 'insert', 'base')),
461 'options->lower_bitfield_insert'),
462
463 (('ibitfield_extract', 'value', 'offset', 'bits'),
464 ('bcsel', ('ilt', 31, 'bits'), 'value',
465 ('ibfe', 'value', 'offset', 'bits')),
466 'options->lower_bitfield_extract'),
467
468 (('ubitfield_extract', 'value', 'offset', 'bits'),
469 ('bcsel', ('ult', 31, 'bits'), 'value',
470 ('ubfe', 'value', 'offset', 'bits')),
471 'options->lower_bitfield_extract'),
472
473 (('extract_i8', a, 'b@32'),
474 ('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
475 'options->lower_extract_byte'),
476
477 (('extract_u8', a, 'b@32'),
478 ('iand', ('ushr', a, ('imul', b, 8)), 0xff),
479 'options->lower_extract_byte'),
480
481 (('extract_i16', a, 'b@32'),
482 ('ishr', ('ishl', a, ('imul', ('isub', 1, b), 16)), 16),
483 'options->lower_extract_word'),
484
485 (('extract_u16', a, 'b@32'),
486 ('iand', ('ushr', a, ('imul', b, 16)), 0xffff),
487 'options->lower_extract_word'),
488
489 (('pack_unorm_2x16', 'v'),
490 ('pack_uvec2_to_uint',
491 ('f2u32', ('fround_even', ('fmul', ('fsat', 'v'), 65535.0)))),
492 'options->lower_pack_unorm_2x16'),
493
494 (('pack_unorm_4x8', 'v'),
495 ('pack_uvec4_to_uint',
496 ('f2u32', ('fround_even', ('fmul', ('fsat', 'v'), 255.0)))),
497 'options->lower_pack_unorm_4x8'),
498
499 (('pack_snorm_2x16', 'v'),
500 ('pack_uvec2_to_uint',
501 ('f2i32', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 32767.0)))),
502 'options->lower_pack_snorm_2x16'),
503
504 (('pack_snorm_4x8', 'v'),
505 ('pack_uvec4_to_uint',
506 ('f2i32', ('fround_even', ('fmul', ('fmin', 1.0, ('fmax', -1.0, 'v')), 127.0)))),
507 'options->lower_pack_snorm_4x8'),
508
509 (('unpack_unorm_2x16', 'v'),
510 ('fdiv', ('u2f32', ('vec2', ('extract_u16', 'v', 0),
511 ('extract_u16', 'v', 1))),
512 65535.0),
513 'options->lower_unpack_unorm_2x16'),
514
515 (('unpack_unorm_4x8', 'v'),
516 ('fdiv', ('u2f32', ('vec4', ('extract_u8', 'v', 0),
517 ('extract_u8', 'v', 1),
518 ('extract_u8', 'v', 2),
519 ('extract_u8', 'v', 3))),
520 255.0),
521 'options->lower_unpack_unorm_4x8'),
522
523 (('unpack_snorm_2x16', 'v'),
524 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f32', ('vec2', ('extract_i16', 'v', 0),
525 ('extract_i16', 'v', 1))),
526 32767.0))),
527 'options->lower_unpack_snorm_2x16'),
528
529 (('unpack_snorm_4x8', 'v'),
530 ('fmin', 1.0, ('fmax', -1.0, ('fdiv', ('i2f32', ('vec4', ('extract_i8', 'v', 0),
531 ('extract_i8', 'v', 1),
532 ('extract_i8', 'v', 2),
533 ('extract_i8', 'v', 3))),
534 127.0))),
535 'options->lower_unpack_snorm_4x8'),
536 ]
537
538 def fexp2i(exp, bits):
539 # We assume that exp is already in the right range.
540 if bits == 32:
541 return ('ishl', ('iadd', exp, 127), 23)
542 elif bits == 64:
543 return ('pack_64_2x32_split', 0, ('ishl', ('iadd', exp, 1023), 20))
544 else:
545 assert False
546
547 def ldexp(f, exp, bits):
548 # First, we clamp exp to a reasonable range. The maximum possible range
549 # for a normal exponent is [-126, 127] and, throwing in denormals, you get
550 # a maximum range of [-149, 127]. This means that we can potentially have
551 # a swing of +-276. If you start with FLT_MAX, you actually have to do
552 # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
553 # spec, on the other hand, only requires that we handle an exponent value
554 # in the range [-126, 128]. This implementation is *mostly* correct; it
555 # handles a range on exp of [-252, 254] which allows you to create any
556 # value (including denorms if the hardware supports it) and to adjust the
557 # exponent of any normal value to anything you want.
558 if bits == 32:
559 exp = ('imin', ('imax', exp, -252), 254)
560 elif bits == 64:
561 exp = ('imin', ('imax', exp, -2044), 2046)
562 else:
563 assert False
564
565 # Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
566 # (We use ishr which isn't the same for -1, but the -1 case still works
567 # since we use exp-exp/2 as the second exponent.) While the spec
568 # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
569 # work with denormals and doesn't allow for the full swing in exponents
570 # that you can get with normalized values. Instead, we create two powers
571 # of two and multiply by them each in turn. That way the effective range
572 # of our exponent is doubled.
573 pow2_1 = fexp2i(('ishr', exp, 1), bits)
574 pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)), bits)
575 return ('fmul', ('fmul', f, pow2_1), pow2_2)
576
577 optimizations += [
578 (('ldexp@32', 'x', 'exp'), ldexp('x', 'exp', 32), 'options->lower_ldexp'),
579 (('ldexp@64', 'x', 'exp'), ldexp('x', 'exp', 64), 'options->lower_ldexp'),
580 ]
581
582 # Unreal Engine 4 demo applications open-codes bitfieldReverse()
583 def bitfield_reverse(u):
584 step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16))
585 step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8))
586 step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4))
587 step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2))
588 step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1))
589
590 return step5
591
592 optimizations += [(bitfield_reverse('x@32'), ('bitfield_reverse', 'x'))]
593
594 # For any float comparison operation, "cmp", if you have "a == a && a cmp b"
595 # then the "a == a" is redundant because it's equivalent to "a is not NaN"
596 # and, if a is a NaN then the second comparison will fail anyway.
597 for op in ['flt', 'fge', 'feq']:
598 optimizations += [
599 (('iand', ('feq', a, a), (op, a, b)), (op, a, b)),
600 (('iand', ('feq', a, a), (op, b, a)), (op, b, a)),
601 ]
602
603 # Add optimizations to handle the case where the result of a ternary is
604 # compared to a constant. This way we can take things like
605 #
606 # (a ? 0 : 1) > 0
607 #
608 # and turn it into
609 #
610 # a ? (0 > 0) : (1 > 0)
611 #
612 # which constant folding will eat for lunch. The resulting ternary will
613 # further get cleaned up by the boolean reductions above and we will be
614 # left with just the original variable "a".
615 for op in ['flt', 'fge', 'feq', 'fne',
616 'ilt', 'ige', 'ieq', 'ine', 'ult', 'uge']:
617 optimizations += [
618 ((op, ('bcsel', 'a', '#b', '#c'), '#d'),
619 ('bcsel', 'a', (op, 'b', 'd'), (op, 'c', 'd'))),
620 ((op, '#d', ('bcsel', a, '#b', '#c')),
621 ('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
622 ]
623
624
625 # For example, this converts things like
626 #
627 # 1 + mix(0, a - 1, condition)
628 #
629 # into
630 #
631 # mix(1, (a-1)+1, condition)
632 #
633 # Other optimizations will rearrange the constants.
634 for op in ['fadd', 'fmul', 'iadd', 'imul']:
635 optimizations += [
636 ((op, ('bcsel(is_used_once)', a, '#b', c), '#d'), ('bcsel', a, (op, b, d), (op, c, d)))
637 ]
638
639 # This section contains "late" optimizations that should be run before
640 # creating ffmas and calling regular optimizations for the final time.
641 # Optimizations should go here if they help code generation and conflict
642 # with the regular optimizations.
643 before_ffma_optimizations = [
644 # Propagate constants down multiplication chains
645 (('~fmul(is_used_once)', ('fmul(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('fmul', ('fmul', a, c), b)),
646 (('imul(is_used_once)', ('imul(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('imul', ('imul', a, c), b)),
647 (('~fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('fadd', ('fadd', a, c), b)),
648 (('iadd(is_used_once)', ('iadd(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('iadd', ('iadd', a, c), b)),
649
650 (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
651 (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
652 (('~fadd', ('fneg', a), a), 0.0),
653 (('iadd', ('ineg', a), a), 0),
654 (('iadd', ('ineg', a), ('iadd', a, b)), b),
655 (('iadd', a, ('iadd', ('ineg', a), b)), b),
656 (('~fadd', ('fneg', a), ('fadd', a, b)), b),
657 (('~fadd', a, ('fadd', ('fneg', a), b)), b),
658 ]
659
660 # This section contains "late" optimizations that should be run after the
661 # regular optimizations have finished. Optimizations should go here if
662 # they help code generation but do not necessarily produce code that is
663 # more easily optimizable.
664 late_optimizations = [
665 # Most of these optimizations aren't quite safe when you get infinity or
666 # Nan involved but the first one should be fine.
667 (('flt', ('fadd', a, b), 0.0), ('flt', a, ('fneg', b))),
668 (('flt', ('fneg', ('fadd', a, b)), 0.0), ('flt', ('fneg', a), b)),
669 (('~fge', ('fadd', a, b), 0.0), ('fge', a, ('fneg', b))),
670 (('~fge', ('fneg', ('fadd', a, b)), 0.0), ('fge', ('fneg', a), b)),
671 (('~feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),
672 (('~fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
673
674 (('~fge', ('fmin(is_used_once)', ('fadd(is_used_once)', a, b), ('fadd', c, d)), 0.0), ('iand', ('fge', a, ('fneg', b)), ('fge', c, ('fneg', d)))),
675
676 (('fdot2', a, b), ('fdot_replicated2', a, b), 'options->fdot_replicates'),
677 (('fdot3', a, b), ('fdot_replicated3', a, b), 'options->fdot_replicates'),
678 (('fdot4', a, b), ('fdot_replicated4', a, b), 'options->fdot_replicates'),
679 (('fdph', a, b), ('fdph_replicated', a, b), 'options->fdot_replicates'),
680
681 (('b2f(is_used_more_than_once)', ('inot', a)), ('bcsel', a, 0.0, 1.0)),
682 (('fneg(is_used_more_than_once)', ('b2f', ('inot', a))), ('bcsel', a, -0.0, -1.0)),
683
684 # we do these late so that we don't get in the way of creating ffmas
685 (('fmin', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c', b)), ('fadd', c, ('fmin', a, b))),
686 (('fmax', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c', b)), ('fadd', c, ('fmax', a, b))),
687 ]
688
689 print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
690 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_before_ffma",
691 before_ffma_optimizations).render()
692 print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
693 late_optimizations).render()