1; RUN: opt -S -jump-threading < %s | FileCheck %s
2
3declare void @foo()
4declare void @bar()
5declare void @baz()
6declare void @quux()
7
8
9; Jump threading of branch with select as condition.
10; Mostly theoretical since instruction combining simplifies all selects of
11; booleans where at least one operand is true/false/undef.
12
13; CHECK-LABEL: @test_br(
14; CHECK-NEXT: entry:
15; CHECK-NEXT: br i1 %cond, label %L1,
16define void @test_br(i1 %cond, i1 %value) nounwind {
17entry:
18  br i1 %cond, label %L0, label %L3
19L0:
20  %expr = select i1 %cond, i1 true, i1 %value
21  br i1 %expr, label %L1, label %L2
22
23L1:
24  call void @foo()
25  ret void
26L2:
27  call void @bar()
28  ret void
29L3:
30  call void @baz()
31  br label %L0
32}
33
34
35; Jump threading of switch with select as condition.
36
37; CHECK-LABEL: @test_switch(
38; CHECK-NEXT: entry:
39; CHECK-NEXT: br i1 %cond, label %L1,
40define void @test_switch(i1 %cond, i8 %value) nounwind {
41entry:
42  br i1 %cond, label %L0, label %L4
43L0:
44  %expr = select i1 %cond, i8 1, i8 %value
45  switch i8 %expr, label %L3 [i8 1, label %L1 i8 2, label %L2]
46
47L1:
48  call void @foo()
49  ret void
50L2:
51  call void @bar()
52  ret void
53L3:
54  call void @baz()
55  ret void
56L4:
57  call void @quux()
58  br label %L0
59}
60
61; Make sure the blocks in the indirectbr test aren't trivially removable as
62; successors by taking their addresses.
63@anchor = constant [3 x i8*] [
64  i8* blockaddress(@test_indirectbr, %L1),
65  i8* blockaddress(@test_indirectbr, %L2),
66  i8* blockaddress(@test_indirectbr, %L3)
67]
68
69
70; Jump threading of indirectbr with select as address.
71
72; CHECK-LABEL: @test_indirectbr(
73; CHECK-NEXT: entry:
74; CHECK-NEXT: br i1 %cond, label %L1, label %L3
75define void @test_indirectbr(i1 %cond, i8* %address) nounwind {
76entry:
77  br i1 %cond, label %L0, label %L3
78L0:
79  %indirect.goto.dest = select i1 %cond, i8* blockaddress(@test_indirectbr, %L1), i8* %address
80  indirectbr i8* %indirect.goto.dest, [label %L1, label %L2, label %L3]
81
82L1:
83  call void @foo()
84  ret void
85L2:
86  call void @bar()
87  ret void
88L3:
89  call void @baz()
90  ret void
91}
92
93
94; Jump threading of indirectbr with select as address.  Test increased
95; duplication threshold for cases where indirectbr is being threaded
96; through.
97
98; CHECK-LABEL: @test_indirectbr_thresh(
99; CHECK-NEXT: entry:
100; CHECK-NEXT: br i1 %cond, label %L1, label %L3
101; CHECK-NOT: indirectbr
102define void @test_indirectbr_thresh(i1 %cond, i8* %address) nounwind {
103entry:
104  br i1 %cond, label %L0, label %L3
105L0:
106  %indirect.goto.dest = select i1 %cond, i8* blockaddress(@test_indirectbr_thresh, %L1), i8* %address
107  call void @quux()
108  call void @quux()
109  call void @quux()
110  indirectbr i8* %indirect.goto.dest, [label %L1, label %L2, label %L3]
111
112L1:
113  call void @foo()
114  ret void
115L2:
116  call void @bar()
117  ret void
118L3:
119  call void @baz()
120  ret void
121}
122
123
124; A more complicated case: the condition is a select based on a comparison.
125
126; CHECK-LABEL: @test_switch_cmp(
127; CHECK-NEXT: entry:
128; CHECK-NEXT: br i1 %cond, label %L0, label %[[THREADED:[A-Za-z.0-9]+]]
129; CHECK: [[THREADED]]:
130; CHECK-NEXT: call void @quux
131; CHECK-NEXT: br label %L1
132define void @test_switch_cmp(i1 %cond, i32 %val, i8 %value) nounwind {
133entry:
134  br i1 %cond, label %L0, label %L4
135L0:
136  %val.phi = phi i32 [%val, %entry], [-1, %L4]
137  %cmp = icmp slt i32 %val.phi, 0
138  %expr = select i1 %cmp, i8 1, i8 %value
139  switch i8 %expr, label %L3 [i8 1, label %L1 i8 2, label %L2]
140
141L1:
142  call void @foo()
143  ret void
144L2:
145  call void @bar()
146  ret void
147L3:
148  call void @baz()
149  ret void
150L4:
151  call void @quux()
152  br label %L0
153}
154
155; Make sure the edge value of %0 from entry to L2 includes 0 and L3 is
156; reachable.
157; CHECK: test_switch_default
158; CHECK: entry:
159; CHECK: load
160; CHECK: switch
161; CHECK: [[THREADED:[A-Za-z.0-9]+]]:
162; CHECK: store
163; CHECK: br
164; CHECK: L2:
165; CHECK-SAME: preds = %entry, %entry
166; CHECK-NEXT: phi i32
167define void @test_switch_default(i32* nocapture %status) nounwind {
168entry:
169  %0 = load i32, i32* %status, align 4
170  switch i32 %0, label %L2 [
171    i32 5061, label %L1
172    i32 0, label %L2
173  ]
174
175L1:
176  store i32 10025, i32* %status, align 4
177  br label %L2
178
179L2:
180  %1 = load i32, i32* %status, align 4
181  %cmp57.i = icmp eq i32 %1, 0
182  br i1 %cmp57.i, label %L3, label %L4
183
184L3:
185  store i32 10000, i32* %status, align 4
186  br label %L4
187
188L4:
189  ret void
190}
191
192define void @unfold1(double %x, double %y) nounwind {
193entry:
194  %sub = fsub double %x, %y
195  %cmp = fcmp ogt double %sub, 1.000000e+01
196  br i1 %cmp, label %cond.end4, label %cond.false
197
198cond.false:                                       ; preds = %entry
199  %add = fadd double %x, %y
200  %cmp1 = fcmp ogt double %add, 1.000000e+01
201  %add. = select i1 %cmp1, double %add, double 0.000000e+00
202  br label %cond.end4
203
204cond.end4:                                        ; preds = %entry, %cond.false
205  %cond5 = phi double [ %add., %cond.false ], [ %sub, %entry ]
206  %cmp6 = fcmp oeq double %cond5, 0.000000e+00
207  br i1 %cmp6, label %if.then, label %if.end
208
209if.then:                                          ; preds = %cond.end4
210  call void @foo()
211  br label %if.end
212
213if.end:                                           ; preds = %if.then, %cond.end4
214  ret void
215
216; CHECK-LABEL: @unfold1
217; CHECK: br i1 %cmp, label %cond.end4, label %cond.false
218; CHECK: br i1 %cmp1, label %cond.end4, label %if.then
219; CHECK: br i1 %cmp6, label %if.then, label %if.end
220; CHECK: br label %if.end
221}
222
223
224define void @unfold2(i32 %x, i32 %y) nounwind {
225entry:
226  %sub = sub nsw i32 %x, %y
227  %cmp = icmp sgt i32 %sub, 10
228  br i1 %cmp, label %cond.end4, label %cond.false
229
230cond.false:                                       ; preds = %entry
231  %add = add nsw i32 %x, %y
232  %cmp1 = icmp sgt i32 %add, 10
233  %add. = select i1 %cmp1, i32 0, i32 %add
234  br label %cond.end4
235
236cond.end4:                                        ; preds = %entry, %cond.false
237  %cond5 = phi i32 [ %add., %cond.false ], [ %sub, %entry ]
238  %cmp6 = icmp eq i32 %cond5, 0
239  br i1 %cmp6, label %if.then, label %if.end
240
241if.then:                                          ; preds = %cond.end4
242  call void @foo()
243  br label %if.end
244
245if.end:                                           ; preds = %if.then, %cond.end4
246  ret void
247
248; CHECK-LABEL: @unfold2
249; CHECK: br i1 %cmp, label %if.end, label %cond.false
250; CHECK: br i1 %cmp1, label %if.then, label %cond.end4
251; CHECK: br i1 %cmp6, label %if.then, label %if.end
252; CHECK: br label %if.end
253}
254
255
256define i32 @unfold3(i32 %u, i32 %v, i32 %w, i32 %x, i32 %y, i32 %z, i32 %j) nounwind {
257entry:
258  %add3 = add nsw i32 %j, 2
259  %cmp.i = icmp slt i32 %u, %v
260  br i1 %cmp.i, label %.exit, label %cond.false.i
261
262cond.false.i:                                     ; preds = %entry
263  %cmp4.i = icmp sgt i32 %u, %v
264  br i1 %cmp4.i, label %.exit, label %cond.false.6.i
265
266cond.false.6.i:                                   ; preds = %cond.false.i
267  %cmp8.i = icmp slt i32 %w, %x
268  br i1 %cmp8.i, label %.exit, label %cond.false.10.i
269
270cond.false.10.i:                                  ; preds = %cond.false.6.i
271  %cmp13.i = icmp sgt i32 %w, %x
272  br i1 %cmp13.i, label %.exit, label %cond.false.15.i
273
274cond.false.15.i:                                  ; preds = %cond.false.10.i
275  %phitmp = icmp sge i32 %y, %z
276  br label %.exit
277
278.exit:                                  ; preds = %entry, %cond.false.i, %cond.false.6.i, %cond.false.10.i, %cond.false.15.i
279  %cond23.i = phi i1 [ false, %entry ], [ true, %cond.false.i ], [ false, %cond.false.6.i ], [ %phitmp, %cond.false.15.i ], [ true, %cond.false.10.i ]
280  %j.add3 = select i1 %cond23.i, i32 %j, i32 %add3
281  ret i32 %j.add3
282
283; CHECK-LABEL: @unfold3
284; CHECK: br i1 %cmp.i, label %.exit.thread3, label %cond.false.i
285; CHECK: br i1 %cmp4.i, label %.exit.thread, label %cond.false.6.i
286; CHECK: br i1 %cmp8.i, label %.exit.thread3, label %cond.false.10.i
287; CHECK: br i1 %cmp13.i, label %.exit.thread, label %.exit
288; CHECK: br i1 %phitmp, label %.exit.thread, label %.exit.thread3
289; CHECK: br label %.exit.thread3
290}
291
292define i32 @unfold4(i32 %u, i32 %v, i32 %w, i32 %x, i32 %y, i32 %z, i32 %j) nounwind {
293entry:
294  %add3 = add nsw i32 %j, 2
295  %cmp.i = icmp slt i32 %u, %v
296  br i1 %cmp.i, label %.exit, label %cond.false.i
297
298cond.false.i:                                     ; preds = %entry
299  %cmp4.i = icmp sgt i32 %u, %v
300  br i1 %cmp4.i, label %.exit, label %cond.false.6.i
301
302cond.false.6.i:                                   ; preds = %cond.false.i
303  %cmp8.i = icmp slt i32 %w, %x
304  br i1 %cmp8.i, label %.exit, label %cond.false.10.i
305
306cond.false.10.i:                                  ; preds = %cond.false.6.i
307  %cmp13.i = icmp sgt i32 %w, %x
308  br i1 %cmp13.i, label %.exit, label %cond.false.15.i
309
310cond.false.15.i:                                  ; preds = %cond.false.10.i
311  %cmp19.i = icmp sge i32 %y, %z
312  %conv = zext i1 %cmp19.i to i32
313  br label %.exit
314
315.exit:                                  ; preds = %entry, %cond.false.i, %cond.false.6.i, %cond.false.10.i, %cond.false.15.i
316  %cond23.i = phi i32 [ 1, %entry ], [ 0, %cond.false.i ], [ 1, %cond.false.6.i ], [ %conv, %cond.false.15.i ], [ 0, %cond.false.10.i ]
317  %lnot.i18 = icmp eq i32 %cond23.i, 1
318  %j.add3 = select i1 %lnot.i18, i32 %j, i32 %add3
319  ret i32 %j.add3
320
321; CHECK-LABEL: @unfold4
322; CHECK: br i1 %cmp.i, label %.exit.thread, label %cond.false.i
323; CHECK: br i1 %cmp4.i, label %.exit.thread4, label %cond.false.6.i
324; CHECK: br i1 %cmp8.i, label %.exit.thread, label %cond.false.10.i
325; CHECK: br i1 %cmp13.i, label %.exit.thread4, label %.exit
326; CHECK: br i1 %lnot.i18, label %.exit.thread, label %.exit.thread4
327; CHECK: br label %.exit.thread4
328}
329
330define i32 @unfold5(i32 %u, i32 %v, i32 %w, i32 %x, i32 %y, i32 %z, i32 %j) nounwind {
331entry:
332  %add3 = add nsw i32 %j, 2
333  %cmp.i = icmp slt i32 %u, %v
334  br i1 %cmp.i, label %.exit, label %cond.false.i
335
336cond.false.i:                                     ; preds = %entry
337  %cmp4.i = icmp sgt i32 %u, %v
338  br i1 %cmp4.i, label %.exit, label %cond.false.6.i
339
340cond.false.6.i:                                   ; preds = %cond.false.i
341  %cmp8.i = icmp slt i32 %w, %x
342  br i1 %cmp8.i, label %.exit, label %cond.false.10.i
343
344cond.false.10.i:                                  ; preds = %cond.false.6.i
345  %cmp13.i = icmp sgt i32 %w, %x
346  br i1 %cmp13.i, label %.exit, label %cond.false.15.i
347
348cond.false.15.i:                                  ; preds = %cond.false.10.i
349  %cmp19.i = icmp sge i32 %y, %z
350  %conv = zext i1 %cmp19.i to i32
351  br label %.exit
352
353.exit:                                  ; preds = %entry, %cond.false.i, %cond.false.6.i, %cond.false.10.i, %cond.false.15.i
354  %cond23.i = phi i32 [ 2, %entry ], [ 3, %cond.false.i ], [ 1, %cond.false.6.i ], [ %conv, %cond.false.15.i ], [ 7, %cond.false.10.i ]
355  %lnot.i18 = icmp sgt i32 %cond23.i, 5
356  %j.add3 = select i1 %lnot.i18, i32 %j, i32 %cond23.i
357  ret i32 %j.add3
358
359; CHECK-LABEL: @unfold5
360; CHECK: br i1 %cmp.i, label %.exit, label %cond.false.i
361; CHECK: br i1 %cmp4.i, label %.exit, label %cond.false.6.i
362; CHECK: br i1 %cmp8.i, label %.exit, label %cond.false.10.i
363; CHECK: br i1 %cmp13.i, label %.exit, label %cond.false.15.i
364; CHECK: br label %.exit
365}
366
367; When a select has a constant operand in one branch, and it feeds a phi node
368; and the phi node feeds a switch we unfold the select
369define void @test_func(i32* nocapture readonly %a, i32* nocapture readonly %b, i32* nocapture readonly %c, i32 %n) local_unnamed_addr #0 {
370entry:
371  br label %for.cond
372
373for.cond:                                         ; preds = %sw.default, %entry
374  %i.0 = phi i32 [ 0, %entry ], [ %inc, %sw.default ]
375  %cmp = icmp slt i32 %i.0, %n
376  br i1 %cmp, label %for.body, label %for.cond.cleanup
377
378for.cond.cleanup:                                 ; preds = %for.cond
379  ret void
380
381for.body:                                         ; preds = %for.cond
382  %0 = zext i32 %i.0 to i64
383  %arrayidx = getelementptr inbounds i32, i32* %a, i64 %0
384  %1 = load i32, i32* %arrayidx, align 4
385  %cmp1 = icmp eq i32 %1, 4
386  br i1 %cmp1, label %land.lhs.true, label %if.end
387
388land.lhs.true:                                    ; preds = %for.body
389  %arrayidx3 = getelementptr inbounds i32, i32* %b, i64 %0
390  %2 = load i32, i32* %arrayidx3, align 4
391  %arrayidx5 = getelementptr inbounds i32, i32* %c, i64 %0
392  %3 = load i32, i32* %arrayidx5, align 4
393  %cmp6 = icmp eq i32 %2, %3
394  %spec.select = select i1 %cmp6, i32 2, i32 4
395  br label %if.end
396
397if.end:                                           ; preds = %land.lhs.true, %for.body
398  %local_var.0 = phi i32 [ %1, %for.body ], [ %spec.select, %land.lhs.true ]
399  switch i32 %local_var.0, label %sw.default [
400    i32 2, label %sw.bb
401    i32 4, label %sw.bb7
402    i32 5, label %sw.bb8
403    i32 7, label %sw.bb9
404  ]
405
406sw.bb:                                            ; preds = %if.end
407  call void @foo()
408  br label %sw.bb7
409
410sw.bb7:                                           ; preds = %if.end, %sw.bb
411  call void @bar()
412  br label %sw.bb8
413
414sw.bb8:                                           ; preds = %if.end, %sw.bb7
415  call void @baz()
416  br label %sw.bb9
417
418sw.bb9:                                           ; preds = %if.end, %sw.bb8
419  call void @quux()
420  br label %sw.default
421
422sw.default:                                       ; preds = %if.end, %sw.bb9
423  call void @baz()
424  %inc = add nuw nsw i32 %i.0, 1
425  br label %for.cond
426
427; CHECK-LABEL: @test_func(
428; CHECK: [[REG:%[0-9]+]] = load
429; CHECK-NOT: select
430; CHECK: br i1
431; CHECK-NOT: select
432; CHECK: br i1 {{.*}}, label [[DEST1:%.*]], label [[DEST2:%.*]]
433
434; The following line checks existence of a phi node, and makes sure
435; it only has one incoming value. To do this, we check every '%'. Note
436; that REG and REG2 each contain one '%;. There is another one in the
437; beginning of the incoming block name. After that there should be no other '%'.
438
439; CHECK: [[REG2:%.*]] = phi i32 {{[^%]*}}[[REG]]{{[^%]*%[^%]*}}
440; CHECK: switch i32 [[REG2]]
441; CHECK: i32 2, label [[DEST1]]
442; CHECK: i32 4, label [[DEST2]]
443}
444
445; FIXME: This is an invalid transform. If %b is false and %x is poison,
446; then the select produces poison (the result of the program is poison).
447; But with this transform, we may be branching on poison, and that is UB.
448
449define i32 @TryToUnfoldSelectInCurrBB(i1 %b, i1 %ui, i32 %s, i1 %x) {
450; CHECK-LABEL: @TryToUnfoldSelectInCurrBB(
451; CHECK-NEXT:  entry:
452; CHECK-NEXT:    br i1 [[B:%.*]], label [[IF_END_THREAD:%.*]], label [[IF_END:%.*]]
453; CHECK:       if.end:
454; CHECK-NEXT:    br i1 [[X:%.*]], label [[TMP0:%.*]], label [[IF_END_THREAD]]
455; CHECK:       0:
456; CHECK-NEXT:    br label [[IF_END_THREAD]]
457; CHECK:       if.end.thread:
458; CHECK-NEXT:    [[TMP1:%.*]] = phi i32 [ [[S:%.*]], [[TMP0]] ], [ 42, [[IF_END]] ], [ 42, [[ENTRY:%.*]] ]
459; CHECK-NEXT:    ret i32 [[TMP1]]
460;
461entry:
462  br i1 %b, label %if.end, label %if.else
463
464if.else:
465  br label %if.end
466
467if.end:
468  %v = phi i1 [ %x, %if.else ], [ false, %entry ]
469  %v1 = select i1 %v, i32 %s, i32 42
470  ret i32 %v1
471}
472