aboutsummaryrefslogtreecommitdiff
path: root/test/codegen/arithmetic.go
blob: eb95416b6aabe38725a79ad3daf4615c4fc31991 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
// asmcheck

// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package codegen

// This file contains codegen tests related to arithmetic
// simplifications and optimizations on integer types.
// For codegen tests on float types, see floats.go.

// ----------------- //
//    Subtraction    //
// ----------------- //

var ef int

func SubMem(arr []int, b, c, d int) int {
	// 386:`SUBL\s[A-Z]+,\s8\([A-Z]+\)`
	// amd64:`SUBQ\s[A-Z]+,\s16\([A-Z]+\)`
	arr[2] -= b
	// 386:`SUBL\s[A-Z]+,\s12\([A-Z]+\)`
	// amd64:`SUBQ\s[A-Z]+,\s24\([A-Z]+\)`
	arr[3] -= b
	// 386:`DECL\s16\([A-Z]+\)`
	arr[4]--
	// 386:`ADDL\s[$]-20,\s20\([A-Z]+\)`
	arr[5] -= 20
	// 386:`SUBL\s\([A-Z]+\)\([A-Z]+\*4\),\s[A-Z]+`
	ef -= arr[b]
	// 386:`SUBL\s[A-Z]+,\s\([A-Z]+\)\([A-Z]+\*4\)`
	arr[c] -= b
	// 386:`ADDL\s[$]-15,\s\([A-Z]+\)\([A-Z]+\*4\)`
	arr[d] -= 15
	// 386:`DECL\s\([A-Z]+\)\([A-Z]+\*4\)`
	arr[b]--
	// amd64:`DECQ\s64\([A-Z]+\)`
	arr[8]--
	// 386:"SUBL\t4"
	// amd64:"SUBQ\t8"
	return arr[0] - arr[1]
}

func SubFromConst(a int) int {
	// ppc64le: `SUBC\tR[0-9]+,\s[$]40,\sR`
	// ppc64: `SUBC\tR[0-9]+,\s[$]40,\sR`
	b := 40 - a
	return b
}

func SubFromConstNeg(a int) int {
	// ppc64le: `ADD\t[$]40,\sR[0-9]+,\sR`
	// ppc64: `ADD\t[$]40,\sR[0-9]+,\sR`
	c := 40 - (-a)
	return c
}

func SubSubFromConst(a int) int {
	// ppc64le: `ADD\t[$]20,\sR[0-9]+,\sR`
	// ppc64: `ADD\t[$]20,\sR[0-9]+,\sR`
	c := 40 - (20 - a)
	return c
}

func AddSubFromConst(a int) int {
	// ppc64le: `SUBC\tR[0-9]+,\s[$]60,\sR`
	// ppc64: `SUBC\tR[0-9]+,\s[$]60,\sR`
	c := 40 + (20 - a)
	return c
}

func NegSubFromConst(a int) int {
	// ppc64le: `ADD\t[$]-20,\sR[0-9]+,\sR`
	// ppc64: `ADD\t[$]-20,\sR[0-9]+,\sR`
	c := -(20 - a)
	return c
}

func NegAddFromConstNeg(a int) int {
	// ppc64le: `SUBC\tR[0-9]+,\s[$]40,\sR`
	// ppc64: `SUBC\tR[0-9]+,\s[$]40,\sR`
	c := -(-40 + a)
	return c
}

func SubSubNegSimplify(a, b int) int {
	// amd64:"NEGQ"
	r := (a - b) - a
	return r
}

func SubAddSimplify(a, b int) int {
	// amd64:-"SUBQ",-"ADDQ"
	r := a + (b - a)
	return r
}

func SubAddNegSimplify(a, b int) int {
	// amd64:"NEGQ",-"ADDQ",-"SUBQ"
	r := a - (b + a)
	return r
}

func AddAddSubSimplify(a, b, c int) int {
	// amd64:-"SUBQ"
	r := a + (b + (c - a))
	return r
}

// -------------------- //
//    Multiplication    //
// -------------------- //

func Pow2Muls(n1, n2 int) (int, int) {
	// amd64:"SHLQ\t[$]5",-"IMULQ"
	// 386:"SHLL\t[$]5",-"IMULL"
	// arm:"SLL\t[$]5",-"MUL"
	// arm64:"LSL\t[$]5",-"MUL"
	// ppc64:"SLD\t[$]5",-"MUL"
	// ppc64le:"SLD\t[$]5",-"MUL"
	a := n1 * 32

	// amd64:"SHLQ\t[$]6",-"IMULQ"
	// 386:"SHLL\t[$]6",-"IMULL"
	// arm:"SLL\t[$]6",-"MUL"
	// arm64:`NEG\sR[0-9]+<<6,\sR[0-9]+`,-`LSL`,-`MUL`
	// ppc64:"SLD\t[$]6","NEG\\sR[0-9]+,\\sR[0-9]+",-"MUL"
	// ppc64le:"SLD\t[$]6","NEG\\sR[0-9]+,\\sR[0-9]+",-"MUL"
	b := -64 * n2

	return a, b
}

func Mul_96(n int) int {
	// amd64:`SHLQ\t[$]5`,`LEAQ\t\(.*\)\(.*\*2\),`,-`IMULQ`
	// 386:`SHLL\t[$]5`,`LEAL\t\(.*\)\(.*\*2\),`,-`IMULL`
	// arm64:`LSL\t[$]5`,`ADD\sR[0-9]+<<1,\sR[0-9]+`,-`MUL`
	// arm:`SLL\t[$]5`,`ADD\sR[0-9]+<<1,\sR[0-9]+`,-`MUL`
	// s390x:`SLD\t[$]5`,`SLD\t[$]6`,-`MULLD`
	return n * 96
}

func Mul_n120(n int) int {
	// s390x:`SLD\t[$]3`,`SLD\t[$]7`,-`MULLD`
	return n * -120
}

func MulMemSrc(a []uint32, b []float32) {
	// 386:`IMULL\s4\([A-Z]+\),\s[A-Z]+`
	a[0] *= a[1]
	// 386/sse2:`MULSS\s4\([A-Z]+\),\sX[0-9]+`
	// amd64:`MULSS\s4\([A-Z]+\),\sX[0-9]+`
	b[0] *= b[1]
}

// Multiplications merging tests

func MergeMuls1(n int) int {
	// amd64:"IMUL3Q\t[$]46"
	// 386:"IMUL3L\t[$]46"
	return 15*n + 31*n // 46n
}

func MergeMuls2(n int) int {
	// amd64:"IMUL3Q\t[$]23","(ADDQ\t[$]29)|(LEAQ\t29)"
	// 386:"IMUL3L\t[$]23","ADDL\t[$]29"
	return 5*n + 7*(n+1) + 11*(n+2) // 23n + 29
}

func MergeMuls3(a, n int) int {
	// amd64:"ADDQ\t[$]19",-"IMULQ\t[$]19"
	// 386:"ADDL\t[$]19",-"IMULL\t[$]19"
	return a*n + 19*n // (a+19)n
}

func MergeMuls4(n int) int {
	// amd64:"IMUL3Q\t[$]14"
	// 386:"IMUL3L\t[$]14"
	return 23*n - 9*n // 14n
}

func MergeMuls5(a, n int) int {
	// amd64:"ADDQ\t[$]-19",-"IMULQ\t[$]19"
	// 386:"ADDL\t[$]-19",-"IMULL\t[$]19"
	return a*n - 19*n // (a-19)n
}

// -------------- //
//    Division    //
// -------------- //

func DivMemSrc(a []float64) {
	// 386/sse2:`DIVSD\s8\([A-Z]+\),\sX[0-9]+`
	// amd64:`DIVSD\s8\([A-Z]+\),\sX[0-9]+`
	a[0] /= a[1]
}

func Pow2Divs(n1 uint, n2 int) (uint, int) {
	// 386:"SHRL\t[$]5",-"DIVL"
	// amd64:"SHRQ\t[$]5",-"DIVQ"
	// arm:"SRL\t[$]5",-".*udiv"
	// arm64:"LSR\t[$]5",-"UDIV"
	// ppc64:"SRD"
	// ppc64le:"SRD"
	a := n1 / 32 // unsigned

	// amd64:"SARQ\t[$]6",-"IDIVQ"
	// 386:"SARL\t[$]6",-"IDIVL"
	// arm:"SRA\t[$]6",-".*udiv"
	// arm64:"ASR\t[$]6",-"SDIV"
	// ppc64:"SRAD"
	// ppc64le:"SRAD"
	b := n2 / 64 // signed

	return a, b
}

// Check that constant divisions get turned into MULs
func ConstDivs(n1 uint, n2 int) (uint, int) {
	// amd64:"MOVQ\t[$]-1085102592571150095","MULQ",-"DIVQ"
	// 386:"MOVL\t[$]-252645135","MULL",-"DIVL"
	// arm64:`MOVD`,`UMULH`,-`DIV`
	// arm:`MOVW`,`MUL`,-`.*udiv`
	a := n1 / 17 // unsigned

	// amd64:"MOVQ\t[$]-1085102592571150095","IMULQ",-"IDIVQ"
	// 386:"MOVL\t[$]-252645135","IMULL",-"IDIVL"
	// arm64:`SMULH`,-`DIV`
	// arm:`MOVW`,`MUL`,-`.*udiv`
	b := n2 / 17 // signed

	return a, b
}

func FloatDivs(a []float32) float32 {
	// amd64:`DIVSS\s8\([A-Z]+\),\sX[0-9]+`
	// 386/sse2:`DIVSS\s8\([A-Z]+\),\sX[0-9]+`
	return a[1] / a[2]
}

func Pow2Mods(n1 uint, n2 int) (uint, int) {
	// 386:"ANDL\t[$]31",-"DIVL"
	// amd64:"ANDQ\t[$]31",-"DIVQ"
	// arm:"AND\t[$]31",-".*udiv"
	// arm64:"AND\t[$]31",-"UDIV"
	// ppc64:"ANDCC\t[$]31"
	// ppc64le:"ANDCC\t[$]31"
	a := n1 % 32 // unsigned

	// 386:"SHRL",-"IDIVL"
	// amd64:"SHRQ",-"IDIVQ"
	// arm:"SRA",-".*udiv"
	// arm64:"ASR",-"REM"
	// ppc64:"SRAD"
	// ppc64le:"SRAD"
	b := n2 % 64 // signed

	return a, b
}

// Check that signed divisibility checks get converted to AND on low bits
func Pow2DivisibleSigned(n1, n2 int) (bool, bool) {
	// 386:"TESTL\t[$]63",-"DIVL",-"SHRL"
	// amd64:"TESTQ\t[$]63",-"DIVQ",-"SHRQ"
	// arm:"AND\t[$]63",-".*udiv",-"SRA"
	// arm64:"AND\t[$]63",-"UDIV",-"ASR"
	// ppc64:"ANDCC\t[$]63",-"SRAD"
	// ppc64le:"ANDCC\t[$]63",-"SRAD"
	a := n1%64 == 0 // signed divisible

	// 386:"TESTL\t[$]63",-"DIVL",-"SHRL"
	// amd64:"TESTQ\t[$]63",-"DIVQ",-"SHRQ"
	// arm:"AND\t[$]63",-".*udiv",-"SRA"
	// arm64:"AND\t[$]63",-"UDIV",-"ASR"
	// ppc64:"ANDCC\t[$]63",-"SRAD"
	// ppc64le:"ANDCC\t[$]63",-"SRAD"
	b := n2%64 != 0 // signed indivisible

	return a, b
}

// Check that constant modulo divs get turned into MULs
func ConstMods(n1 uint, n2 int) (uint, int) {
	// amd64:"MOVQ\t[$]-1085102592571150095","MULQ",-"DIVQ"
	// 386:"MOVL\t[$]-252645135","MULL",-"DIVL"
	// arm64:`MOVD`,`UMULH`,-`DIV`
	// arm:`MOVW`,`MUL`,-`.*udiv`
	a := n1 % 17 // unsigned

	// amd64:"MOVQ\t[$]-1085102592571150095","IMULQ",-"IDIVQ"
	// 386:"MOVL\t[$]-252645135","IMULL",-"IDIVL"
	// arm64:`SMULH`,-`DIV`
	// arm:`MOVW`,`MUL`,-`.*udiv`
	b := n2 % 17 // signed

	return a, b
}

// Check that divisibility checks x%c==0 are converted to MULs and rotates
func Divisible(n1 uint, n2 int) (bool, bool, bool, bool) {
	// amd64:"MOVQ\t[$]-6148914691236517205","IMULQ","ROLQ\t[$]63",-"DIVQ"
	// 386:"IMUL3L\t[$]-1431655765","ROLL\t[$]31",-"DIVQ"
	// arm64:"MOVD\t[$]-6148914691236517205","MUL","ROR",-"DIV"
	// arm:"MUL","CMP\t[$]715827882",-".*udiv"
	// ppc64:"MULLD","ROTL\t[$]63"
	// ppc64le:"MULLD","ROTL\t[$]63"
	evenU := n1%6 == 0

	// amd64:"MOVQ\t[$]-8737931403336103397","IMULQ",-"ROLQ",-"DIVQ"
	// 386:"IMUL3L\t[$]678152731",-"ROLL",-"DIVQ"
	// arm64:"MOVD\t[$]-8737931403336103397","MUL",-"ROR",-"DIV"
	// arm:"MUL","CMP\t[$]226050910",-".*udiv"
	// ppc64:"MULLD",-"ROTL"
	// ppc64le:"MULLD",-"ROTL"
	oddU := n1%19 == 0

	// amd64:"IMULQ","ADD","ROLQ\t[$]63",-"DIVQ"
	// 386:"IMUL3L\t[$]-1431655765","ADDL\t[$]715827882","ROLL\t[$]31",-"DIVQ"
	// arm64:"MUL","ADD\t[$]3074457345618258602","ROR",-"DIV"
	// arm:"MUL","ADD\t[$]715827882",-".*udiv"
	// ppc64/power8:"MULLD","ADD","ROTL\t[$]63"
	// ppc64le/power8:"MULLD","ADD","ROTL\t[$]63"
	// ppc64/power9:"MADDLD","ROTL\t[$]63"
	// ppc64le/power9:"MADDLD","ROTL\t[$]63"
	evenS := n2%6 == 0

	// amd64:"IMULQ","ADD",-"ROLQ",-"DIVQ"
	// 386:"IMUL3L\t[$]678152731","ADDL\t[$]113025455",-"ROLL",-"DIVQ"
	// arm64:"MUL","ADD\t[$]485440633518672410",-"ROR",-"DIV"
	// arm:"MUL","ADD\t[$]113025455",-".*udiv"
	// ppc64/power8:"MULLD","ADD",-"ROTL"
	// ppc64/power9:"MADDLD",-"ROTL"
	// ppc64le/power8:"MULLD","ADD",-"ROTL"
	// ppc64le/power9:"MADDLD",-"ROTL"
	oddS := n2%19 == 0

	return evenU, oddU, evenS, oddS
}

// Check that fix-up code is not generated for divisions where it has been proven that
// that the divisor is not -1 or that the dividend is > MinIntNN.
func NoFix64A(divr int64) (int64, int64) {
	var d int64 = 42
	var e int64 = 84
	if divr > 5 {
		d /= divr // amd64:-"JMP"
		e %= divr // amd64:-"JMP"
		// The following statement is to avoid conflict between the above check
		// and the normal JMP generated at the end of the block.
		d += e
	}
	return d, e
}

func NoFix64B(divd int64) (int64, int64) {
	var d int64
	var e int64
	var divr int64 = -1
	if divd > -9223372036854775808 {
		d = divd / divr // amd64:-"JMP"
		e = divd % divr // amd64:-"JMP"
		d += e
	}
	return d, e
}

func NoFix32A(divr int32) (int32, int32) {
	var d int32 = 42
	var e int32 = 84
	if divr > 5 {
		// amd64:-"JMP"
		// 386:-"JMP"
		d /= divr
		// amd64:-"JMP"
		// 386:-"JMP"
		e %= divr
		d += e
	}
	return d, e
}

func NoFix32B(divd int32) (int32, int32) {
	var d int32
	var e int32
	var divr int32 = -1
	if divd > -2147483648 {
		// amd64:-"JMP"
		// 386:-"JMP"
		d = divd / divr
		// amd64:-"JMP"
		// 386:-"JMP"
		e = divd % divr
		d += e
	}
	return d, e
}

func NoFix16A(divr int16) (int16, int16) {
	var d int16 = 42
	var e int16 = 84
	if divr > 5 {
		// amd64:-"JMP"
		// 386:-"JMP"
		d /= divr
		// amd64:-"JMP"
		// 386:-"JMP"
		e %= divr
		d += e
	}
	return d, e
}

func NoFix16B(divd int16) (int16, int16) {
	var d int16
	var e int16
	var divr int16 = -1
	if divd > -32768 {
		// amd64:-"JMP"
		// 386:-"JMP"
		d = divd / divr
		// amd64:-"JMP"
		// 386:-"JMP"
		e = divd % divr
		d += e
	}
	return d, e
}

// Check that len() and cap() calls divided by powers of two are
// optimized into shifts and ands

func LenDiv1(a []int) int {
	// 386:"SHRL\t[$]10"
	// amd64:"SHRQ\t[$]10"
	// arm64:"LSR\t[$]10",-"SDIV"
	// arm:"SRL\t[$]10",-".*udiv"
	// ppc64:"SRD"\t[$]10"
	// ppc64le:"SRD"\t[$]10"
	return len(a) / 1024
}

func LenDiv2(s string) int {
	// 386:"SHRL\t[$]11"
	// amd64:"SHRQ\t[$]11"
	// arm64:"LSR\t[$]11",-"SDIV"
	// arm:"SRL\t[$]11",-".*udiv"
	// ppc64:"SRD\t[$]11"
	// ppc64le:"SRD\t[$]11"
	return len(s) / (4097 >> 1)
}

func LenMod1(a []int) int {
	// 386:"ANDL\t[$]1023"
	// amd64:"ANDQ\t[$]1023"
	// arm64:"AND\t[$]1023",-"SDIV"
	// arm/6:"AND",-".*udiv"
	// arm/7:"BFC",-".*udiv",-"AND"
	// ppc64:"ANDCC\t[$]1023"
	// ppc64le:"ANDCC\t[$]1023"
	return len(a) % 1024
}

func LenMod2(s string) int {
	// 386:"ANDL\t[$]2047"
	// amd64:"ANDQ\t[$]2047"
	// arm64:"AND\t[$]2047",-"SDIV"
	// arm/6:"AND",-".*udiv"
	// arm/7:"BFC",-".*udiv",-"AND"
	// ppc64:"ANDCC\t[$]2047"
	// ppc64le:"ANDCC\t[$]2047"
	return len(s) % (4097 >> 1)
}

func CapDiv(a []int) int {
	// 386:"SHRL\t[$]12"
	// amd64:"SHRQ\t[$]12"
	// arm64:"LSR\t[$]12",-"SDIV"
	// arm:"SRL\t[$]12",-".*udiv"
	// ppc64:"SRD\t[$]12"
	// ppc64le:"SRD\t[$]12"
	return cap(a) / ((1 << 11) + 2048)
}

func CapMod(a []int) int {
	// 386:"ANDL\t[$]4095"
	// amd64:"ANDQ\t[$]4095"
	// arm64:"AND\t[$]4095",-"SDIV"
	// arm/6:"AND",-".*udiv"
	// arm/7:"BFC",-".*udiv",-"AND"
	// ppc64:"ANDCC\t[$]4095"
	// ppc64le:"ANDCC\t[$]4095"
	return cap(a) % ((1 << 11) + 2048)
}

func AddMul(x int) int {
	// amd64:"LEAQ\t1"
	return 2*x + 1
}

func MULA(a, b, c uint32) (uint32, uint32, uint32) {
	// arm:`MULA`,-`MUL\s`
	// arm64:`MADDW`,-`MULW`
	r0 := a*b + c
	// arm:`MULA`,-`MUL\s`
	// arm64:`MADDW`,-`MULW`
	r1 := c*79 + a
	// arm:`ADD`,-`MULA`,-`MUL\s`
	// arm64:`ADD`,-`MADD`,-`MULW`
	r2 := b*64 + c
	return r0, r1, r2
}

func MULS(a, b, c uint32) (uint32, uint32, uint32) {
	// arm/7:`MULS`,-`MUL\s`
	// arm/6:`SUB`,`MUL\s`,-`MULS`
	// arm64:`MSUBW`,-`MULW`
	r0 := c - a*b
	// arm/7:`MULS`,-`MUL\s`
	// arm/6:`SUB`,`MUL\s`,-`MULS`
	// arm64:`MSUBW`,-`MULW`
	r1 := a - c*79
	// arm/7:`SUB`,-`MULS`,-`MUL\s`
	// arm64:`SUB`,-`MSUBW`,-`MULW`
	r2 := c - b*64
	return r0, r1, r2
}

func addSpecial(a, b, c uint32) (uint32, uint32, uint32) {
	// amd64:`INCL`
	a++
	// amd64:`DECL`
	b--
	// amd64:`SUBL.*-128`
	c += 128
	return a, b, c
}

// Divide -> shift rules usually require fixup for negative inputs.
// If the input is non-negative, make sure the fixup is eliminated.
func divInt(v int64) int64 {
	if v < 0 {
		return 0
	}
	// amd64:-`.*SARQ.*63,`, -".*SHRQ", ".*SARQ.*[$]9,"
	return v / 512
}

// The reassociate rules "x - (z + C) -> (x - z) - C" and
// "(z + C) -x -> C + (z - x)" can optimize the following cases.
func constantFold1(i0, j0, i1, j1, i2, j2, i3, j3 int) (int, int, int, int) {
	// arm64:"SUB","ADD\t[$]2"
	r0 := (i0 + 3) - (j0 + 1)
	// arm64:"SUB","SUB\t[$]4"
	r1 := (i1 - 3) - (j1 + 1)
	// arm64:"SUB","ADD\t[$]4"
	r2 := (i2 + 3) - (j2 - 1)
	// arm64:"SUB","SUB\t[$]2"
	r3 := (i3 - 3) - (j3 - 1)
	return r0, r1, r2, r3
}

// The reassociate rules "x - (z + C) -> (x - z) - C" and
// "(C - z) - x -> C - (z + x)" can optimize the following cases.
func constantFold2(i0, j0, i1, j1 int) (int, int) {
	// arm64:"ADD","MOVD\t[$]2","SUB"
	r0 := (3 - i0) - (j0 + 1)
	// arm64:"ADD","MOVD\t[$]4","SUB"
	r1 := (3 - i1) - (j1 - 1)
	return r0, r1
}

func constantFold3(i, j int) int {
	// arm64: "MOVD\t[$]30","MUL",-"ADD",-"LSL"
	r := (5 * i) * (6 * j)
	return r
}