xref: /llvm-project/llvm/test/Transforms/IndVarSimplify/promote-iv-to-eliminate-casts.ll (revision ffb2af3ed6a95a4eb55b81a3d1351d5d4bd66eb5)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; RUN: opt < %s -passes=indvars -S | FileCheck %s
3
4; Provide legal integer types.
5target datalayout = "n8:16:32:64"
6
7; CHECK-NOT: sext
8
9define i64 @test(ptr nocapture %first, i32 %count) nounwind readonly {
10; CHECK-LABEL: @test(
11; CHECK-NEXT:  entry:
12; CHECK-NEXT:    [[T0:%.*]] = icmp sgt i32 [[COUNT:%.*]], 0
13; CHECK-NEXT:    br i1 [[T0]], label [[BB_NPH:%.*]], label [[BB2:%.*]]
14; CHECK:       bb.nph:
15; CHECK-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[COUNT]] to i64
16; CHECK-NEXT:    br label [[BB:%.*]]
17; CHECK:       bb:
18; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[BB1:%.*]] ], [ 0, [[BB_NPH]] ]
19; CHECK-NEXT:    [[RESULT_02:%.*]] = phi i64 [ [[T5:%.*]], [[BB1]] ], [ 0, [[BB_NPH]] ]
20; CHECK-NEXT:    [[T2:%.*]] = getelementptr i64, ptr [[FIRST:%.*]], i64 [[INDVARS_IV]]
21; CHECK-NEXT:    [[T3:%.*]] = load i64, ptr [[T2]], align 8
22; CHECK-NEXT:    [[T4:%.*]] = lshr i64 [[T3]], 4
23; CHECK-NEXT:    [[T5]] = add i64 [[T4]], [[RESULT_02]]
24; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
25; CHECK-NEXT:    br label [[BB1]]
26; CHECK:       bb1:
27; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[INDVARS_IV_NEXT]], [[WIDE_TRIP_COUNT]]
28; CHECK-NEXT:    br i1 [[EXITCOND]], label [[BB]], label [[BB1_BB2_CRIT_EDGE:%.*]]
29; CHECK:       bb1.bb2_crit_edge:
30; CHECK-NEXT:    [[DOTLCSSA:%.*]] = phi i64 [ [[T5]], [[BB1]] ]
31; CHECK-NEXT:    br label [[BB2]]
32; CHECK:       bb2:
33; CHECK-NEXT:    [[RESULT_0_LCSSA:%.*]] = phi i64 [ [[DOTLCSSA]], [[BB1_BB2_CRIT_EDGE]] ], [ 0, [[ENTRY:%.*]] ]
34; CHECK-NEXT:    ret i64 [[RESULT_0_LCSSA]]
35;
36entry:
37  %t0 = icmp sgt i32 %count, 0		; <i1> [#uses=1]
38  br i1 %t0, label %bb.nph, label %bb2
39
40bb.nph:		; preds = %entry
41  br label %bb
42
43bb:		; preds = %bb1, %bb.nph
44  %result.02 = phi i64 [ %t5, %bb1 ], [ 0, %bb.nph ]		; <i64> [#uses=1]
45  %n.01 = phi i32 [ %t6, %bb1 ], [ 0, %bb.nph ]		; <i32> [#uses=2]
46  %t1 = sext i32 %n.01 to i64		; <i64> [#uses=1]
47  %t2 = getelementptr i64, ptr %first, i64 %t1		; <ptr> [#uses=1]
48  %t3 = load i64, ptr %t2, align 8		; <i64> [#uses=1]
49  %t4 = lshr i64 %t3, 4		; <i64> [#uses=1]
50  %t5 = add i64 %t4, %result.02		; <i64> [#uses=2]
51  %t6 = add i32 %n.01, 1		; <i32> [#uses=2]
52  br label %bb1
53
54bb1:		; preds = %bb
55  %t7 = icmp slt i32 %t6, %count		; <i1> [#uses=1]
56  br i1 %t7, label %bb, label %bb1.bb2_crit_edge
57
58bb1.bb2_crit_edge:		; preds = %bb1
59  %.lcssa = phi i64 [ %t5, %bb1 ]		; <i64> [#uses=1]
60  br label %bb2
61
62bb2:		; preds = %bb1.bb2_crit_edge, %entry
63  %result.0.lcssa = phi i64 [ %.lcssa, %bb1.bb2_crit_edge ], [ 0, %entry ]		; <i64> [#uses=1]
64  ret i64 %result.0.lcssa
65}
66
67define void @foo(i16 signext %N, ptr nocapture %P) nounwind {
68; CHECK-LABEL: @foo(
69; CHECK-NEXT:  entry:
70; CHECK-NEXT:    [[T0:%.*]] = icmp sgt i16 [[N:%.*]], 0
71; CHECK-NEXT:    br i1 [[T0]], label [[BB_NPH:%.*]], label [[RETURN:%.*]]
72; CHECK:       bb.nph:
73; CHECK-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i16 [[N]] to i64
74; CHECK-NEXT:    br label [[BB:%.*]]
75; CHECK:       bb:
76; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[BB1:%.*]] ], [ 0, [[BB_NPH]] ]
77; CHECK-NEXT:    [[T2:%.*]] = getelementptr i32, ptr [[P:%.*]], i64 [[INDVARS_IV]]
78; CHECK-NEXT:    store i32 123, ptr [[T2]], align 4
79; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
80; CHECK-NEXT:    br label [[BB1]]
81; CHECK:       bb1:
82; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[INDVARS_IV_NEXT]], [[WIDE_TRIP_COUNT]]
83; CHECK-NEXT:    br i1 [[EXITCOND]], label [[BB]], label [[BB1_RETURN_CRIT_EDGE:%.*]]
84; CHECK:       bb1.return_crit_edge:
85; CHECK-NEXT:    br label [[RETURN]]
86; CHECK:       return:
87; CHECK-NEXT:    ret void
88;
89entry:
90  %t0 = icmp sgt i16 %N, 0		; <i1> [#uses=1]
91  br i1 %t0, label %bb.nph, label %return
92
93bb.nph:		; preds = %entry
94  br label %bb
95
96bb:		; preds = %bb1, %bb.nph
97  %i.01 = phi i16 [ %t3, %bb1 ], [ 0, %bb.nph ]		; <i16> [#uses=2]
98  %t1 = sext i16 %i.01 to i64		; <i64> [#uses=1]
99  %t2 = getelementptr i32, ptr %P, i64 %t1		; <ptr> [#uses=1]
100  store i32 123, ptr %t2, align 4
101  %t3 = add i16 %i.01, 1		; <i16> [#uses=2]
102  br label %bb1
103
104bb1:		; preds = %bb
105  %t4 = icmp slt i16 %t3, %N		; <i1> [#uses=1]
106  br i1 %t4, label %bb, label %bb1.return_crit_edge
107
108bb1.return_crit_edge:		; preds = %bb1
109  br label %return
110
111return:		; preds = %bb1.return_crit_edge, %entry
112  ret void
113}
114
115; Test cases from PR1301:
116
117define void @kinds__srangezero(ptr nocapture %a) nounwind {
118; CHECK-LABEL: @kinds__srangezero(
119; CHECK-NEXT:  bb.thread:
120; CHECK-NEXT:    br label [[BB:%.*]]
121; CHECK:       bb:
122; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i32 [ [[INDVARS_IV_NEXT:%.*]], [[BB]] ], [ -10, [[BB_THREAD:%.*]] ]
123; CHECK-NEXT:    [[TMP4:%.*]] = add nsw i32 [[INDVARS_IV]], 10
124; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr [21 x i32], ptr [[A:%.*]], i32 0, i32 [[TMP4]]
125; CHECK-NEXT:    store i32 0, ptr [[TMP5]], align 4
126; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nsw i32 [[INDVARS_IV]], 1
127; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp eq i32 [[INDVARS_IV_NEXT]], 11
128; CHECK-NEXT:    br i1 [[EXITCOND]], label [[RETURN:%.*]], label [[BB]]
129; CHECK:       return:
130; CHECK-NEXT:    ret void
131;
132bb.thread:
133  br label %bb
134
135bb:             ; preds = %bb, %bb.thread
136  %i.0.reg2mem.0 = phi i8 [ -10, %bb.thread ], [ %tmp7, %bb ]           ; <i8> [#uses=2]
137  %tmp12 = sext i8 %i.0.reg2mem.0 to i32                ; <i32> [#uses=1]
138  %tmp4 = add i32 %tmp12, 10            ; <i32> [#uses=1]
139  %tmp5 = getelementptr [21 x i32], ptr %a, i32 0, i32 %tmp4                ; <ptr> [#uses=1]
140  store i32 0, ptr %tmp5
141  %tmp7 = add i8 %i.0.reg2mem.0, 1              ; <i8> [#uses=2]
142  %0 = icmp sgt i8 %tmp7, 10            ; <i1> [#uses=1]
143  br i1 %0, label %return, label %bb
144
145return:         ; preds = %bb
146  ret void
147}
148
149define void @kinds__urangezero(ptr nocapture %a) nounwind {
150; CHECK-LABEL: @kinds__urangezero(
151; CHECK-NEXT:  bb.thread:
152; CHECK-NEXT:    br label [[BB:%.*]]
153; CHECK:       bb:
154; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i32 [ [[INDVARS_IV_NEXT:%.*]], [[BB]] ], [ 10, [[BB_THREAD:%.*]] ]
155; CHECK-NEXT:    [[TMP4:%.*]] = add nsw i32 [[INDVARS_IV]], -10
156; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr [21 x i32], ptr [[A:%.*]], i32 0, i32 [[TMP4]]
157; CHECK-NEXT:    store i32 0, ptr [[TMP5]], align 4
158; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i32 [[INDVARS_IV]], 1
159; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp eq i32 [[INDVARS_IV_NEXT]], 31
160; CHECK-NEXT:    br i1 [[EXITCOND]], label [[RETURN:%.*]], label [[BB]]
161; CHECK:       return:
162; CHECK-NEXT:    ret void
163;
164bb.thread:
165  br label %bb
166
167bb:             ; preds = %bb, %bb.thread
168  %i.0.reg2mem.0 = phi i8 [ 10, %bb.thread ], [ %tmp7, %bb ]            ; <i8> [#uses=2]
169  %tmp12 = sext i8 %i.0.reg2mem.0 to i32                ; <i32> [#uses=1]
170  %tmp4 = add i32 %tmp12, -10           ; <i32> [#uses=1]
171  %tmp5 = getelementptr [21 x i32], ptr %a, i32 0, i32 %tmp4                ; <ptr> [#uses=1]
172  store i32 0, ptr %tmp5
173  %tmp7 = add i8 %i.0.reg2mem.0, 1              ; <i8> [#uses=2]
174  %0 = icmp sgt i8 %tmp7, 30            ; <i1> [#uses=1]
175  br i1 %0, label %return, label %bb
176
177return:         ; preds = %bb
178  ret void
179}
180
181define void @promote_latch_condition_decrementing_loop_01(ptr %p, ptr %a) {
182; CHECK-LABEL: @promote_latch_condition_decrementing_loop_01(
183; CHECK-NEXT:  entry:
184; CHECK-NEXT:    [[LEN:%.*]] = load i32, ptr [[P:%.*]], align 4, !range [[RNG0:![0-9]+]]
185; CHECK-NEXT:    [[LEN_MINUS_1:%.*]] = add nsw i32 [[LEN]], -1
186; CHECK-NEXT:    [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0
187; CHECK-NEXT:    br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]]
188; CHECK:       preheader:
189; CHECK-NEXT:    [[TMP0:%.*]] = zext i32 [[LEN_MINUS_1]] to i64
190; CHECK-NEXT:    br label [[LOOP:%.*]]
191; CHECK:       loopexit.loopexit:
192; CHECK-NEXT:    br label [[LOOPEXIT]]
193; CHECK:       loopexit:
194; CHECK-NEXT:    ret void
195; CHECK:       loop:
196; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP0]], [[PREHEADER]] ]
197; CHECK-NEXT:    [[EL:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDVARS_IV]]
198; CHECK-NEXT:    store atomic i32 0, ptr [[EL]] unordered, align 4
199; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1
200; CHECK-NEXT:    [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1
201; CHECK-NEXT:    br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]]
202;
203
204entry:
205  %len = load i32, ptr %p, align 4, !range !0
206  %len.minus.1 = add nsw i32 %len, -1
207  %zero_check = icmp eq i32 %len, 0
208  br i1 %zero_check, label %loopexit, label %preheader
209
210preheader:
211  br label %loop
212
213loopexit:
214  ret void
215
216loop:
217  %iv = phi i32 [ %iv.next, %loop ], [ %len.minus.1, %preheader ]
218  %iv.wide = zext i32 %iv to i64
219  %el = getelementptr inbounds i32, ptr %a, i64 %iv.wide
220  store atomic i32 0, ptr %el unordered, align 4
221  %iv.next = add nsw i32 %iv, -1
222  %loopcond = icmp slt i32 %iv, 1
223  br i1 %loopcond, label %loopexit, label %loop
224}
225
226define void @promote_latch_condition_decrementing_loop_02(ptr %p, ptr %a) {
227; CHECK-LABEL: @promote_latch_condition_decrementing_loop_02(
228; CHECK-NEXT:  entry:
229; CHECK-NEXT:    [[LEN:%.*]] = load i32, ptr [[P:%.*]], align 4, !range [[RNG0]]
230; CHECK-NEXT:    [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0
231; CHECK-NEXT:    br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]]
232; CHECK:       preheader:
233; CHECK-NEXT:    [[TMP0:%.*]] = zext nneg i32 [[LEN]] to i64
234; CHECK-NEXT:    br label [[LOOP:%.*]]
235; CHECK:       loopexit.loopexit:
236; CHECK-NEXT:    br label [[LOOPEXIT]]
237; CHECK:       loopexit:
238; CHECK-NEXT:    ret void
239; CHECK:       loop:
240; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP0]], [[PREHEADER]] ]
241; CHECK-NEXT:    [[EL:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDVARS_IV]]
242; CHECK-NEXT:    store atomic i32 0, ptr [[EL]] unordered, align 4
243; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1
244; CHECK-NEXT:    [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1
245; CHECK-NEXT:    br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]]
246;
247
248entry:
249  %len = load i32, ptr %p, align 4, !range !0
250  %zero_check = icmp eq i32 %len, 0
251  br i1 %zero_check, label %loopexit, label %preheader
252
253preheader:
254  br label %loop
255
256loopexit:
257  ret void
258
259loop:
260  %iv = phi i32 [ %iv.next, %loop ], [ %len, %preheader ]
261  %iv.wide = zext i32 %iv to i64
262  %el = getelementptr inbounds i32, ptr %a, i64 %iv.wide
263  store atomic i32 0, ptr %el unordered, align 4
264  %iv.next = add nsw i32 %iv, -1
265  %loopcond = icmp slt i32 %iv, 1
266  br i1 %loopcond, label %loopexit, label %loop
267}
268
269define void @promote_latch_condition_decrementing_loop_03(ptr %p, ptr %a) {
270; CHECK-LABEL: @promote_latch_condition_decrementing_loop_03(
271; CHECK-NEXT:  entry:
272; CHECK-NEXT:    [[LEN:%.*]] = load i32, ptr [[P:%.*]], align 4, !range [[RNG0]]
273; CHECK-NEXT:    [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0
274; CHECK-NEXT:    br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]]
275; CHECK:       preheader:
276; CHECK-NEXT:    [[TMP0:%.*]] = zext nneg i32 [[LEN]] to i64
277; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i64 [[TMP0]], 1
278; CHECK-NEXT:    br label [[LOOP:%.*]]
279; CHECK:       loopexit.loopexit:
280; CHECK-NEXT:    br label [[LOOPEXIT]]
281; CHECK:       loopexit:
282; CHECK-NEXT:    ret void
283; CHECK:       loop:
284; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP1]], [[PREHEADER]] ]
285; CHECK-NEXT:    [[EL:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDVARS_IV]]
286; CHECK-NEXT:    store atomic i32 0, ptr [[EL]] unordered, align 4
287; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1
288; CHECK-NEXT:    [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1
289; CHECK-NEXT:    br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]]
290;
291
292entry:
293  %len = load i32, ptr %p, align 4, !range !0
294  %len.plus.1 = add i32 %len, 1
295  %zero_check = icmp eq i32 %len, 0
296  br i1 %zero_check, label %loopexit, label %preheader
297
298preheader:
299  br label %loop
300
301loopexit:
302  ret void
303
304loop:
305  %iv = phi i32 [ %iv.next, %loop ], [ %len.plus.1, %preheader ]
306  %iv.wide = zext i32 %iv to i64
307  %el = getelementptr inbounds i32, ptr %a, i64 %iv.wide
308  store atomic i32 0, ptr %el unordered, align 4
309  %iv.next = add nsw i32 %iv, -1
310  %loopcond = icmp slt i32 %iv, 1
311  br i1 %loopcond, label %loopexit, label %loop
312}
313
314define void @promote_latch_condition_decrementing_loop_04(ptr %p, ptr %a, i1 %cond) {
315; CHECK-LABEL: @promote_latch_condition_decrementing_loop_04(
316; CHECK-NEXT:  entry:
317; CHECK-NEXT:    [[LEN:%.*]] = load i32, ptr [[P:%.*]], align 4, !range [[RNG0]]
318; CHECK-NEXT:    [[LEN_MINUS_1:%.*]] = add nsw i32 [[LEN]], -1
319; CHECK-NEXT:    br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
320; CHECK:       if.true:
321; CHECK-NEXT:    br label [[MERGE:%.*]]
322; CHECK:       if.false:
323; CHECK-NEXT:    br label [[MERGE]]
324; CHECK:       merge:
325; CHECK-NEXT:    [[IV_START:%.*]] = phi i32 [ [[LEN]], [[IF_TRUE]] ], [ [[LEN_MINUS_1]], [[IF_FALSE]] ]
326; CHECK-NEXT:    [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0
327; CHECK-NEXT:    br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]]
328; CHECK:       preheader:
329; CHECK-NEXT:    [[TMP0:%.*]] = zext i32 [[IV_START]] to i64
330; CHECK-NEXT:    br label [[LOOP:%.*]]
331; CHECK:       loopexit.loopexit:
332; CHECK-NEXT:    br label [[LOOPEXIT]]
333; CHECK:       loopexit:
334; CHECK-NEXT:    ret void
335; CHECK:       loop:
336; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP0]], [[PREHEADER]] ]
337; CHECK-NEXT:    [[EL:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDVARS_IV]]
338; CHECK-NEXT:    store atomic i32 0, ptr [[EL]] unordered, align 4
339; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1
340; CHECK-NEXT:    [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1
341; CHECK-NEXT:    br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]]
342;
343
344entry:
345  %len = load i32, ptr %p, align 4, !range !0
346  %len.minus.1 = add nsw i32 %len, -1
347  br i1 %cond, label %if.true, label %if.false
348
349if.true:
350  br label %merge
351
352if.false:
353  br label %merge
354
355merge:
356  %iv_start = phi i32 [ %len, %if.true ], [%len.minus.1, %if.false ]
357  %zero_check = icmp eq i32 %len, 0
358  br i1 %zero_check, label %loopexit, label %preheader
359
360preheader:
361  br label %loop
362
363loopexit:
364  ret void
365
366loop:
367  %iv = phi i32 [ %iv.next, %loop ], [ %iv_start, %preheader ]
368  %iv.wide = zext i32 %iv to i64
369  %el = getelementptr inbounds i32, ptr %a, i64 %iv.wide
370  store atomic i32 0, ptr %el unordered, align 4
371  %iv.next = add nsw i32 %iv, -1
372  %loopcond = icmp slt i32 %iv, 1
373  br i1 %loopcond, label %loopexit, label %loop
374}
375
376define void @promote_latch_condition_decrementing_loop_05(ptr %p, ptr %a, i1 %cond) {
377; CHECK-LABEL: @promote_latch_condition_decrementing_loop_05(
378; CHECK-NEXT:  entry:
379; CHECK-NEXT:    [[LEN:%.*]] = load i32, ptr [[P:%.*]], align 4, !range [[RNG0]]
380; CHECK-NEXT:    br i1 [[COND:%.*]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
381; CHECK:       if.true:
382; CHECK-NEXT:    br label [[MERGE:%.*]]
383; CHECK:       if.false:
384; CHECK-NEXT:    [[LEN_MINUS_1:%.*]] = add nsw i32 [[LEN]], -1
385; CHECK-NEXT:    br label [[MERGE]]
386; CHECK:       merge:
387; CHECK-NEXT:    [[IV_START:%.*]] = phi i32 [ [[LEN]], [[IF_TRUE]] ], [ [[LEN_MINUS_1]], [[IF_FALSE]] ]
388; CHECK-NEXT:    [[ZERO_CHECK:%.*]] = icmp eq i32 [[LEN]], 0
389; CHECK-NEXT:    br i1 [[ZERO_CHECK]], label [[LOOPEXIT:%.*]], label [[PREHEADER:%.*]]
390; CHECK:       preheader:
391; CHECK-NEXT:    [[TMP0:%.*]] = zext i32 [[IV_START]] to i64
392; CHECK-NEXT:    br label [[LOOP:%.*]]
393; CHECK:       loopexit.loopexit:
394; CHECK-NEXT:    br label [[LOOPEXIT]]
395; CHECK:       loopexit:
396; CHECK-NEXT:    ret void
397; CHECK:       loop:
398; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[LOOP]] ], [ [[TMP0]], [[PREHEADER]] ]
399; CHECK-NEXT:    [[EL:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], i64 [[INDVARS_IV]]
400; CHECK-NEXT:    store atomic i32 0, ptr [[EL]] unordered, align 4
401; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1
402; CHECK-NEXT:    [[LOOPCOND:%.*]] = icmp slt i64 [[INDVARS_IV]], 1
403; CHECK-NEXT:    br i1 [[LOOPCOND]], label [[LOOPEXIT_LOOPEXIT:%.*]], label [[LOOP]]
404;
405
406entry:
407  %len = load i32, ptr %p, align 4, !range !0
408  br i1 %cond, label %if.true, label %if.false
409
410if.true:
411  br label %merge
412
413if.false:
414  %len.minus.1 = add nsw i32 %len, -1
415  br label %merge
416
417merge:
418  %iv_start = phi i32 [ %len, %if.true ], [%len.minus.1, %if.false ]
419  %zero_check = icmp eq i32 %len, 0
420  br i1 %zero_check, label %loopexit, label %preheader
421
422preheader:
423  br label %loop
424
425loopexit:
426  ret void
427
428loop:
429  %iv = phi i32 [ %iv.next, %loop ], [ %iv_start, %preheader ]
430  %iv.wide = zext i32 %iv to i64
431  %el = getelementptr inbounds i32, ptr %a, i64 %iv.wide
432  store atomic i32 0, ptr %el unordered, align 4
433  %iv.next = add nsw i32 %iv, -1
434  %loopcond = icmp slt i32 %iv, 1
435  br i1 %loopcond, label %loopexit, label %loop
436}
437
438!0 = !{i32 0, i32 2147483647}
439