File: sextw-removal.ll

package info (click to toggle)
llvm-toolchain-14 1%3A14.0.6-12
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 1,496,180 kB
  • sloc: cpp: 5,593,972; ansic: 986,872; asm: 585,869; python: 184,223; objc: 72,530; lisp: 31,119; f90: 27,793; javascript: 9,780; pascal: 9,762; sh: 9,482; perl: 7,468; ml: 5,432; awk: 3,523; makefile: 2,538; xml: 953; cs: 573; fortran: 567
file content (421 lines) | stat: -rw-r--r-- 13,986 bytes parent folder | download | duplicates (3)
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
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -mtriple=riscv64 -mattr=+m,+f \
; RUN:   | FileCheck %s --check-prefixes=CHECK,RV64I
; RUN: llc < %s -mtriple=riscv64 -mattr=+m,+zbb,+f \
; RUN:   | FileCheck %s --check-prefixes=CHECK,RV64ZBB
; RUN: llc < %s -mtriple=riscv64 -mattr=+m,+zbb,+f \
; RUN:   -riscv-disable-sextw-removal | FileCheck %s --check-prefix=NOREMOVAL

define void @test1(i32 signext %arg, i32 signext %arg1) nounwind {
; CHECK-LABEL: test1:
; CHECK:       # %bb.0: # %bb
; CHECK-NEXT:    addi sp, sp, -32
; CHECK-NEXT:    sd ra, 24(sp) # 8-byte Folded Spill
; CHECK-NEXT:    sd s0, 16(sp) # 8-byte Folded Spill
; CHECK-NEXT:    sd s1, 8(sp) # 8-byte Folded Spill
; CHECK-NEXT:    mv s0, a1
; CHECK-NEXT:    sraw s1, a0, a1
; CHECK-NEXT:  .LBB0_1: # %bb2
; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
; CHECK-NEXT:    mv a0, s1
; CHECK-NEXT:    call bar@plt
; CHECK-NEXT:    sllw s1, s1, s0
; CHECK-NEXT:    bnez a0, .LBB0_1
; CHECK-NEXT:  # %bb.2: # %bb7
; CHECK-NEXT:    ld ra, 24(sp) # 8-byte Folded Reload
; CHECK-NEXT:    ld s0, 16(sp) # 8-byte Folded Reload
; CHECK-NEXT:    ld s1, 8(sp) # 8-byte Folded Reload
; CHECK-NEXT:    addi sp, sp, 32
; CHECK-NEXT:    ret
;
; NOREMOVAL-LABEL: test1:
; NOREMOVAL:       # %bb.0: # %bb
; NOREMOVAL-NEXT:    addi sp, sp, -32
; NOREMOVAL-NEXT:    sd ra, 24(sp) # 8-byte Folded Spill
; NOREMOVAL-NEXT:    sd s0, 16(sp) # 8-byte Folded Spill
; NOREMOVAL-NEXT:    sd s1, 8(sp) # 8-byte Folded Spill
; NOREMOVAL-NEXT:    mv s0, a1
; NOREMOVAL-NEXT:    sraw s1, a0, a1
; NOREMOVAL-NEXT:  .LBB0_1: # %bb2
; NOREMOVAL-NEXT:    # =>This Inner Loop Header: Depth=1
; NOREMOVAL-NEXT:    sext.w a0, s1
; NOREMOVAL-NEXT:    call bar@plt
; NOREMOVAL-NEXT:    sllw s1, s1, s0
; NOREMOVAL-NEXT:    bnez a0, .LBB0_1
; NOREMOVAL-NEXT:  # %bb.2: # %bb7
; NOREMOVAL-NEXT:    ld ra, 24(sp) # 8-byte Folded Reload
; NOREMOVAL-NEXT:    ld s0, 16(sp) # 8-byte Folded Reload
; NOREMOVAL-NEXT:    ld s1, 8(sp) # 8-byte Folded Reload
; NOREMOVAL-NEXT:    addi sp, sp, 32
; NOREMOVAL-NEXT:    ret
bb:
  %i = ashr i32 %arg, %arg1
  br label %bb2

bb2:                                              ; preds = %bb2, %bb
  %i3 = phi i32 [ %i, %bb ], [ %i5, %bb2 ]
  %i4 = tail call signext i32 @bar(i32 signext %i3)
  %i5 = shl i32 %i3, %arg1
  %i6 = icmp eq i32 %i4, 0
  br i1 %i6, label %bb7, label %bb2

bb7:                                              ; preds = %bb2
  ret void
}

declare signext i32 @bar(i32 signext)

; The load here will be an anyext load in isel and sext.w will be emitted for
; the ret. Make sure we can look through logic ops to prove the sext.w is
; unnecessary.
define signext i32 @test2(i32* %p, i32 signext %b) nounwind {
; RV64I-LABEL: test2:
; RV64I:       # %bb.0:
; RV64I-NEXT:    lw a0, 0(a0)
; RV64I-NEXT:    li a2, 1
; RV64I-NEXT:    sllw a1, a2, a1
; RV64I-NEXT:    not a1, a1
; RV64I-NEXT:    and a0, a1, a0
; RV64I-NEXT:    ret
;
; RV64ZBB-LABEL: test2:
; RV64ZBB:       # %bb.0:
; RV64ZBB-NEXT:    lw a0, 0(a0)
; RV64ZBB-NEXT:    li a2, 1
; RV64ZBB-NEXT:    sllw a1, a2, a1
; RV64ZBB-NEXT:    andn a0, a0, a1
; RV64ZBB-NEXT:    ret
;
; NOREMOVAL-LABEL: test2:
; NOREMOVAL:       # %bb.0:
; NOREMOVAL-NEXT:    lw a0, 0(a0)
; NOREMOVAL-NEXT:    li a2, 1
; NOREMOVAL-NEXT:    sllw a1, a2, a1
; NOREMOVAL-NEXT:    andn a0, a0, a1
; NOREMOVAL-NEXT:    sext.w a0, a0
; NOREMOVAL-NEXT:    ret
  %a = load i32, i32* %p
  %shl = shl i32 1, %b
  %neg = xor i32 %shl, -1
  %and1 = and i32 %neg, %a
  ret i32 %and1
}

define signext i32 @test3(i32* %p, i32 signext %b) nounwind {
; RV64I-LABEL: test3:
; RV64I:       # %bb.0:
; RV64I-NEXT:    lw a0, 0(a0)
; RV64I-NEXT:    li a2, 1
; RV64I-NEXT:    sllw a1, a2, a1
; RV64I-NEXT:    not a1, a1
; RV64I-NEXT:    or a0, a1, a0
; RV64I-NEXT:    ret
;
; RV64ZBB-LABEL: test3:
; RV64ZBB:       # %bb.0:
; RV64ZBB-NEXT:    lw a0, 0(a0)
; RV64ZBB-NEXT:    li a2, 1
; RV64ZBB-NEXT:    sllw a1, a2, a1
; RV64ZBB-NEXT:    orn a0, a0, a1
; RV64ZBB-NEXT:    ret
;
; NOREMOVAL-LABEL: test3:
; NOREMOVAL:       # %bb.0:
; NOREMOVAL-NEXT:    lw a0, 0(a0)
; NOREMOVAL-NEXT:    li a2, 1
; NOREMOVAL-NEXT:    sllw a1, a2, a1
; NOREMOVAL-NEXT:    orn a0, a0, a1
; NOREMOVAL-NEXT:    sext.w a0, a0
; NOREMOVAL-NEXT:    ret
  %a = load i32, i32* %p
  %shl = shl i32 1, %b
  %neg = xor i32 %shl, -1
  %and1 = or i32 %neg, %a
  ret i32 %and1
}

define signext i32 @test4(i32* %p, i32 signext %b) nounwind {
; RV64I-LABEL: test4:
; RV64I:       # %bb.0:
; RV64I-NEXT:    lw a0, 0(a0)
; RV64I-NEXT:    li a2, 1
; RV64I-NEXT:    sllw a1, a2, a1
; RV64I-NEXT:    xor a0, a1, a0
; RV64I-NEXT:    not a0, a0
; RV64I-NEXT:    ret
;
; RV64ZBB-LABEL: test4:
; RV64ZBB:       # %bb.0:
; RV64ZBB-NEXT:    lw a0, 0(a0)
; RV64ZBB-NEXT:    li a2, 1
; RV64ZBB-NEXT:    sllw a1, a2, a1
; RV64ZBB-NEXT:    xnor a0, a1, a0
; RV64ZBB-NEXT:    ret
;
; NOREMOVAL-LABEL: test4:
; NOREMOVAL:       # %bb.0:
; NOREMOVAL-NEXT:    lw a0, 0(a0)
; NOREMOVAL-NEXT:    li a2, 1
; NOREMOVAL-NEXT:    sllw a1, a2, a1
; NOREMOVAL-NEXT:    xnor a0, a1, a0
; NOREMOVAL-NEXT:    sext.w a0, a0
; NOREMOVAL-NEXT:    ret
  %a = load i32, i32* %p
  %shl = shl i32 1, %b
  %neg = xor i32 %shl, -1
  %and1 = xor i32 %neg, %a
  ret i32 %and1
}

; Make sure we don't put a sext.w before bar when using cpopw.
define void @test5(i32 signext %arg, i32 signext %arg1) nounwind {
; RV64I-LABEL: test5:
; RV64I:       # %bb.0: # %bb
; RV64I-NEXT:    addi sp, sp, -48
; RV64I-NEXT:    sd ra, 40(sp) # 8-byte Folded Spill
; RV64I-NEXT:    sd s0, 32(sp) # 8-byte Folded Spill
; RV64I-NEXT:    sd s1, 24(sp) # 8-byte Folded Spill
; RV64I-NEXT:    sd s2, 16(sp) # 8-byte Folded Spill
; RV64I-NEXT:    sd s3, 8(sp) # 8-byte Folded Spill
; RV64I-NEXT:    sraw a0, a0, a1
; RV64I-NEXT:    lui a1, 349525
; RV64I-NEXT:    addiw s0, a1, 1365
; RV64I-NEXT:    lui a1, 209715
; RV64I-NEXT:    addiw s1, a1, 819
; RV64I-NEXT:    lui a1, 61681
; RV64I-NEXT:    addiw s2, a1, -241
; RV64I-NEXT:    lui a1, 4112
; RV64I-NEXT:    addiw s3, a1, 257
; RV64I-NEXT:  .LBB4_1: # %bb2
; RV64I-NEXT:    # =>This Inner Loop Header: Depth=1
; RV64I-NEXT:    call bar@plt
; RV64I-NEXT:    mv a1, a0
; RV64I-NEXT:    srli a0, a0, 1
; RV64I-NEXT:    and a0, a0, s0
; RV64I-NEXT:    subw a0, a1, a0
; RV64I-NEXT:    and a2, a0, s1
; RV64I-NEXT:    srli a0, a0, 2
; RV64I-NEXT:    and a0, a0, s1
; RV64I-NEXT:    add a0, a2, a0
; RV64I-NEXT:    srli a2, a0, 4
; RV64I-NEXT:    add a0, a0, a2
; RV64I-NEXT:    and a0, a0, s2
; RV64I-NEXT:    mulw a0, a0, s3
; RV64I-NEXT:    srliw a0, a0, 24
; RV64I-NEXT:    bnez a1, .LBB4_1
; RV64I-NEXT:  # %bb.2: # %bb7
; RV64I-NEXT:    ld ra, 40(sp) # 8-byte Folded Reload
; RV64I-NEXT:    ld s0, 32(sp) # 8-byte Folded Reload
; RV64I-NEXT:    ld s1, 24(sp) # 8-byte Folded Reload
; RV64I-NEXT:    ld s2, 16(sp) # 8-byte Folded Reload
; RV64I-NEXT:    ld s3, 8(sp) # 8-byte Folded Reload
; RV64I-NEXT:    addi sp, sp, 48
; RV64I-NEXT:    ret
;
; RV64ZBB-LABEL: test5:
; RV64ZBB:       # %bb.0: # %bb
; RV64ZBB-NEXT:    addi sp, sp, -16
; RV64ZBB-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
; RV64ZBB-NEXT:    sraw a0, a0, a1
; RV64ZBB-NEXT:  .LBB4_1: # %bb2
; RV64ZBB-NEXT:    # =>This Inner Loop Header: Depth=1
; RV64ZBB-NEXT:    call bar@plt
; RV64ZBB-NEXT:    mv a1, a0
; RV64ZBB-NEXT:    cpopw a0, a0
; RV64ZBB-NEXT:    bnez a1, .LBB4_1
; RV64ZBB-NEXT:  # %bb.2: # %bb7
; RV64ZBB-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
; RV64ZBB-NEXT:    addi sp, sp, 16
; RV64ZBB-NEXT:    ret
;
; NOREMOVAL-LABEL: test5:
; NOREMOVAL:       # %bb.0: # %bb
; NOREMOVAL-NEXT:    addi sp, sp, -16
; NOREMOVAL-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
; NOREMOVAL-NEXT:    sraw a1, a0, a1
; NOREMOVAL-NEXT:  .LBB4_1: # %bb2
; NOREMOVAL-NEXT:    # =>This Inner Loop Header: Depth=1
; NOREMOVAL-NEXT:    sext.w a0, a1
; NOREMOVAL-NEXT:    call bar@plt
; NOREMOVAL-NEXT:    cpopw a1, a0
; NOREMOVAL-NEXT:    bnez a0, .LBB4_1
; NOREMOVAL-NEXT:  # %bb.2: # %bb7
; NOREMOVAL-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
; NOREMOVAL-NEXT:    addi sp, sp, 16
; NOREMOVAL-NEXT:    ret
bb:
  %i = ashr i32 %arg, %arg1
  br label %bb2

bb2:                                              ; preds = %bb2, %bb
  %i3 = phi i32 [ %i, %bb ], [ %i5, %bb2 ]
  %i4 = tail call signext i32 @bar(i32 signext %i3)
  %i5 = tail call i32 @llvm.ctpop.i32(i32 %i4)
  %i6 = icmp eq i32 %i4, 0
  br i1 %i6, label %bb7, label %bb2

bb7:                                              ; preds = %bb2
  ret void
}

declare i32 @llvm.ctpop.i32(i32)

define void @test6(i32 signext %arg, i32 signext %arg1) nounwind {
; CHECK-LABEL: test6:
; CHECK:       # %bb.0: # %bb
; CHECK-NEXT:    addi sp, sp, -16
; CHECK-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
; CHECK-NEXT:    sraw a0, a0, a1
; CHECK-NEXT:    fmv.w.x ft0, zero
; CHECK-NEXT:    fsw ft0, 4(sp) # 4-byte Folded Spill
; CHECK-NEXT:  .LBB5_1: # %bb2
; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
; CHECK-NEXT:    call baz@plt
; CHECK-NEXT:    fmv.w.x ft0, a0
; CHECK-NEXT:    flw ft1, 4(sp) # 4-byte Folded Reload
; CHECK-NEXT:    feq.s a1, ft0, ft1
; CHECK-NEXT:    fcvt.w.s a0, ft0, rtz
; CHECK-NEXT:    beqz a1, .LBB5_1
; CHECK-NEXT:  # %bb.2: # %bb7
; CHECK-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
; CHECK-NEXT:    addi sp, sp, 16
; CHECK-NEXT:    ret
;
; NOREMOVAL-LABEL: test6:
; NOREMOVAL:       # %bb.0: # %bb
; NOREMOVAL-NEXT:    addi sp, sp, -16
; NOREMOVAL-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
; NOREMOVAL-NEXT:    sraw a0, a0, a1
; NOREMOVAL-NEXT:    fmv.w.x ft0, zero
; NOREMOVAL-NEXT:    fsw ft0, 4(sp) # 4-byte Folded Spill
; NOREMOVAL-NEXT:  .LBB5_1: # %bb2
; NOREMOVAL-NEXT:    # =>This Inner Loop Header: Depth=1
; NOREMOVAL-NEXT:    sext.w a0, a0
; NOREMOVAL-NEXT:    call baz@plt
; NOREMOVAL-NEXT:    fmv.w.x ft0, a0
; NOREMOVAL-NEXT:    flw ft1, 4(sp) # 4-byte Folded Reload
; NOREMOVAL-NEXT:    feq.s a1, ft0, ft1
; NOREMOVAL-NEXT:    fcvt.w.s a0, ft0, rtz
; NOREMOVAL-NEXT:    beqz a1, .LBB5_1
; NOREMOVAL-NEXT:  # %bb.2: # %bb7
; NOREMOVAL-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
; NOREMOVAL-NEXT:    addi sp, sp, 16
; NOREMOVAL-NEXT:    ret
bb:
  %i = ashr i32 %arg, %arg1
  br label %bb2

bb2:                                              ; preds = %bb2, %bb
  %i3 = phi i32 [ %i, %bb ], [ %i5, %bb2 ]
  %i4 = tail call float @baz(i32 signext %i3)
  %i5 = fptosi float %i4 to i32
  %i6 = fcmp oeq float %i4, zeroinitializer
  br i1 %i6, label %bb7, label %bb2

bb7:                                              ; preds = %bb2
  ret void
}
declare float @baz(i32 signext %i3)

define void @test8(i32 signext %arg, i32 signext %arg1) nounwind {
; CHECK-LABEL: test8:
; CHECK:       # %bb.0: # %bb
; CHECK-NEXT:    addi sp, sp, -16
; CHECK-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
; CHECK-NEXT:    sraw a0, a0, a1
; CHECK-NEXT:  .LBB6_1: # %bb2
; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
; CHECK-NEXT:    call foo@plt
; CHECK-NEXT:    ori a0, a0, -256
; CHECK-NEXT:    bnez a0, .LBB6_1
; CHECK-NEXT:  # %bb.2: # %bb7
; CHECK-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
; CHECK-NEXT:    addi sp, sp, 16
; CHECK-NEXT:    ret
;
; NOREMOVAL-LABEL: test8:
; NOREMOVAL:       # %bb.0: # %bb
; NOREMOVAL-NEXT:    addi sp, sp, -16
; NOREMOVAL-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
; NOREMOVAL-NEXT:    sraw a0, a0, a1
; NOREMOVAL-NEXT:  .LBB6_1: # %bb2
; NOREMOVAL-NEXT:    # =>This Inner Loop Header: Depth=1
; NOREMOVAL-NEXT:    sext.w a0, a0
; NOREMOVAL-NEXT:    call foo@plt
; NOREMOVAL-NEXT:    ori a0, a0, -256
; NOREMOVAL-NEXT:    bnez a0, .LBB6_1
; NOREMOVAL-NEXT:  # %bb.2: # %bb7
; NOREMOVAL-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
; NOREMOVAL-NEXT:    addi sp, sp, 16
; NOREMOVAL-NEXT:    ret
bb:
  %i = ashr i32 %arg, %arg1
  br label %bb2

bb2:                                              ; preds = %bb2, %bb
  %i3 = phi i32 [ %i, %bb ], [ %i6, %bb2 ]
  %i4 = tail call signext i64 @foo(i32 signext %i3)
  %i5 = or i64 %i4, -256
  %i6 = trunc i64 %i5 to i32
  %i7 = icmp eq i32 %i6, 0
  br i1 %i7, label %bb7, label %bb2

bb7:                                              ; preds = %bb2
  ret void
}

declare i64 @foo(i32 signext)

define void @test9(i32 signext %arg, i32 signext %arg1) nounwind {
; CHECK-LABEL: test9:
; CHECK:       # %bb.0: # %bb
; CHECK-NEXT:    addi sp, sp, -16
; CHECK-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
; CHECK-NEXT:    sd s0, 0(sp) # 8-byte Folded Spill
; CHECK-NEXT:    sraw a0, a0, a1
; CHECK-NEXT:    li s0, 254
; CHECK-NEXT:  .LBB7_1: # %bb2
; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
; CHECK-NEXT:    call bar@plt
; CHECK-NEXT:    mv a1, a0
; CHECK-NEXT:    slti a0, a0, 255
; CHECK-NEXT:    blt s0, a1, .LBB7_1
; CHECK-NEXT:  # %bb.2: # %bb7
; CHECK-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
; CHECK-NEXT:    ld s0, 0(sp) # 8-byte Folded Reload
; CHECK-NEXT:    addi sp, sp, 16
; CHECK-NEXT:    ret
;
; NOREMOVAL-LABEL: test9:
; NOREMOVAL:       # %bb.0: # %bb
; NOREMOVAL-NEXT:    addi sp, sp, -16
; NOREMOVAL-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
; NOREMOVAL-NEXT:    sd s0, 0(sp) # 8-byte Folded Spill
; NOREMOVAL-NEXT:    sraw a1, a0, a1
; NOREMOVAL-NEXT:    li s0, 254
; NOREMOVAL-NEXT:  .LBB7_1: # %bb2
; NOREMOVAL-NEXT:    # =>This Inner Loop Header: Depth=1
; NOREMOVAL-NEXT:    sext.w a0, a1
; NOREMOVAL-NEXT:    call bar@plt
; NOREMOVAL-NEXT:    slti a1, a0, 255
; NOREMOVAL-NEXT:    blt s0, a0, .LBB7_1
; NOREMOVAL-NEXT:  # %bb.2: # %bb7
; NOREMOVAL-NEXT:    ld ra, 8(sp) # 8-byte Folded Reload
; NOREMOVAL-NEXT:    ld s0, 0(sp) # 8-byte Folded Reload
; NOREMOVAL-NEXT:    addi sp, sp, 16
; NOREMOVAL-NEXT:    ret
bb:
  %i = ashr i32 %arg, %arg1
  br label %bb2

bb2:                                              ; preds = %bb2, %bb
  %i3 = phi i32 [ %i, %bb ], [ %i7, %bb2 ]
  %i4 = tail call signext i32 @bar(i32 signext %i3)
  %i5 = icmp slt i32 %i4, 255
  %i6 = sext i1 %i5 to i32
  %i7 = sub i32 0, %i6
  br i1 %i5, label %bb7, label %bb2

bb7:                                              ; preds = %bb2
  ret void
}