1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; RUN: opt -S -loop-vectorize -instcombine -force-vector-width=2 -force-vector-interleave=1 -enable-interleaved-mem-accesses < %s | FileCheck %s
3; RUN: opt -S -loop-vectorize -instcombine -force-vector-width=2 -force-vector-interleave=1 -enable-interleaved-mem-accesses -enable-masked-interleaved-mem-accesses < %s | FileCheck %s
4
5target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
6%pair = type { i64, i64 }
7
8; Ensure that we vectorize the interleaved load group even though the loop
9; contains a conditional store. The store group contains gaps and is not
10; vectorized.
11;
12;
13;
14;
15;
16
17define void @interleaved_with_cond_store_0(%pair *%p, i64 %x, i64 %n) {
18; CHECK-LABEL: @interleaved_with_cond_store_0(
19; CHECK-NEXT:  entry:
20; CHECK-NEXT:    [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[N:%.*]], i64 1)
21; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[SMAX]], 3
22; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
23; CHECK:       vector.ph:
24; CHECK-NEXT:    [[N_MOD_VF:%.*]] = and i64 [[SMAX]], 1
25; CHECK-NEXT:    [[TMP0:%.*]] = icmp eq i64 [[N_MOD_VF]], 0
26; CHECK-NEXT:    [[TMP1:%.*]] = select i1 [[TMP0]], i64 2, i64 [[N_MOD_VF]]
27; CHECK-NEXT:    [[N_VEC:%.*]] = sub nsw i64 [[SMAX]], [[TMP1]]
28; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[X:%.*]], i64 0
29; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
30; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
31; CHECK:       vector.body:
32; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[PRED_STORE_CONTINUE2:%.*]] ]
33; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds [[PAIR:%.*]], %pair* [[P:%.*]], i64 [[INDEX]], i32 1
34; CHECK-NEXT:    [[TMP3:%.*]] = bitcast i64* [[TMP2]] to <4 x i64>*
35; CHECK-NEXT:    [[WIDE_VEC:%.*]] = load <4 x i64>, <4 x i64>* [[TMP3]], align 8
36; CHECK-NEXT:    [[STRIDED_VEC:%.*]] = shufflevector <4 x i64> [[WIDE_VEC]], <4 x i64> poison, <2 x i32> <i32 0, i32 2>
37; CHECK-NEXT:    [[TMP4:%.*]] = icmp eq <2 x i64> [[STRIDED_VEC]], [[BROADCAST_SPLAT]]
38; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x i1> [[TMP4]], i64 0
39; CHECK-NEXT:    br i1 [[TMP5]], label [[PRED_STORE_IF:%.*]], label [[PRED_STORE_CONTINUE:%.*]]
40; CHECK:       pred.store.if:
41; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <4 x i64> [[WIDE_VEC]], i64 0
42; CHECK-NEXT:    store i64 [[TMP6]], i64* [[TMP2]], align 8
43; CHECK-NEXT:    br label [[PRED_STORE_CONTINUE]]
44; CHECK:       pred.store.continue:
45; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x i1> [[TMP4]], i64 1
46; CHECK-NEXT:    br i1 [[TMP7]], label [[PRED_STORE_IF1:%.*]], label [[PRED_STORE_CONTINUE2]]
47; CHECK:       pred.store.if1:
48; CHECK-NEXT:    [[TMP8:%.*]] = or i64 [[INDEX]], 1
49; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[TMP8]], i32 1
50; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <4 x i64> [[WIDE_VEC]], i64 2
51; CHECK-NEXT:    store i64 [[TMP10]], i64* [[TMP9]], align 8
52; CHECK-NEXT:    br label [[PRED_STORE_CONTINUE2]]
53; CHECK:       pred.store.continue2:
54; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
55; CHECK-NEXT:    [[TMP11:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
56; CHECK-NEXT:    br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
57; CHECK:       middle.block:
58; CHECK-NEXT:    br label [[SCALAR_PH]]
59; CHECK:       scalar.ph:
60; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
61; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
62; CHECK:       for.body:
63; CHECK-NEXT:    [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[IF_MERGE:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
64; CHECK-NEXT:    [[P_1:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[I]], i32 1
65; CHECK-NEXT:    [[TMP12:%.*]] = load i64, i64* [[P_1]], align 8
66; CHECK-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[TMP12]], [[X]]
67; CHECK-NEXT:    br i1 [[TMP13]], label [[IF_THEN:%.*]], label [[IF_MERGE]]
68; CHECK:       if.then:
69; CHECK-NEXT:    store i64 [[TMP12]], i64* [[P_1]], align 8
70; CHECK-NEXT:    br label [[IF_MERGE]]
71; CHECK:       if.merge:
72; CHECK-NEXT:    [[I_NEXT]] = add nuw nsw i64 [[I]], 1
73; CHECK-NEXT:    [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
74; CHECK-NEXT:    br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END:%.*]], !llvm.loop [[LOOP2:![0-9]+]]
75; CHECK:       for.end:
76; CHECK-NEXT:    ret void
77;
78entry:
79  br label %for.body
80
81for.body:
82  %i  = phi i64 [ %i.next, %if.merge ], [ 0, %entry ]
83  %p.1 = getelementptr inbounds %pair, %pair* %p, i64 %i, i32 1
84  %0 = load i64, i64* %p.1, align 8
85  %1 = icmp eq i64 %0, %x
86  br i1 %1, label %if.then, label %if.merge
87
88if.then:
89  store i64 %0, i64* %p.1, align 8
90  br label %if.merge
91
92if.merge:
93  %i.next = add nuw nsw i64 %i, 1
94  %cond = icmp slt i64 %i.next, %n
95  br i1 %cond, label %for.body, label %for.end
96
97for.end:
98  ret void
99}
100
101; Ensure that we don't form a single interleaved group for the two loads. The
102; conditional store prevents the second load from being hoisted. The two load
103; groups are separately vectorized. The store group contains gaps and is not
104; vectorized.
105;
106;
107;
108;
109;
110;
111
112define void @interleaved_with_cond_store_1(%pair *%p, i64 %x, i64 %n) {
113; CHECK-LABEL: @interleaved_with_cond_store_1(
114; CHECK-NEXT:  entry:
115; CHECK-NEXT:    [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[N:%.*]], i64 1)
116; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[SMAX]], 3
117; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
118; CHECK:       vector.ph:
119; CHECK-NEXT:    [[N_MOD_VF:%.*]] = and i64 [[SMAX]], 1
120; CHECK-NEXT:    [[TMP0:%.*]] = icmp eq i64 [[N_MOD_VF]], 0
121; CHECK-NEXT:    [[TMP1:%.*]] = select i1 [[TMP0]], i64 2, i64 [[N_MOD_VF]]
122; CHECK-NEXT:    [[N_VEC:%.*]] = sub nsw i64 [[SMAX]], [[TMP1]]
123; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[X:%.*]], i64 0
124; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
125; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
126; CHECK:       vector.body:
127; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[PRED_STORE_CONTINUE2:%.*]] ]
128; CHECK-NEXT:    [[TMP2:%.*]] = or i64 [[INDEX]], 1
129; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds [[PAIR:%.*]], %pair* [[P:%.*]], i64 [[INDEX]], i32 0
130; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[INDEX]], i32 1
131; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[TMP2]], i32 1
132; CHECK-NEXT:    [[TMP6:%.*]] = bitcast i64* [[TMP4]] to <4 x i64>*
133; CHECK-NEXT:    [[WIDE_VEC:%.*]] = load <4 x i64>, <4 x i64>* [[TMP6]], align 8
134; CHECK-NEXT:    [[STRIDED_VEC:%.*]] = shufflevector <4 x i64> [[WIDE_VEC]], <4 x i64> poison, <2 x i32> <i32 0, i32 2>
135; CHECK-NEXT:    [[TMP7:%.*]] = icmp eq <2 x i64> [[STRIDED_VEC]], [[BROADCAST_SPLAT]]
136; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x i1> [[TMP7]], i64 0
137; CHECK-NEXT:    br i1 [[TMP8]], label [[PRED_STORE_IF:%.*]], label [[PRED_STORE_CONTINUE:%.*]]
138; CHECK:       pred.store.if:
139; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <4 x i64> [[WIDE_VEC]], i64 0
140; CHECK-NEXT:    store i64 [[TMP9]], i64* [[TMP3]], align 8
141; CHECK-NEXT:    br label [[PRED_STORE_CONTINUE]]
142; CHECK:       pred.store.continue:
143; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <2 x i1> [[TMP7]], i64 1
144; CHECK-NEXT:    br i1 [[TMP10]], label [[PRED_STORE_IF1:%.*]], label [[PRED_STORE_CONTINUE2]]
145; CHECK:       pred.store.if1:
146; CHECK-NEXT:    [[TMP11:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[TMP2]], i32 0
147; CHECK-NEXT:    [[TMP12:%.*]] = extractelement <4 x i64> [[WIDE_VEC]], i64 2
148; CHECK-NEXT:    store i64 [[TMP12]], i64* [[TMP11]], align 8
149; CHECK-NEXT:    br label [[PRED_STORE_CONTINUE2]]
150; CHECK:       pred.store.continue2:
151; CHECK-NEXT:    [[TMP13:%.*]] = bitcast i64* [[TMP3]] to <4 x i64>*
152; CHECK-NEXT:    [[WIDE_VEC3:%.*]] = load <4 x i64>, <4 x i64>* [[TMP13]], align 8
153; CHECK-NEXT:    [[TMP14:%.*]] = extractelement <4 x i64> [[WIDE_VEC3]], i64 0
154; CHECK-NEXT:    store i64 [[TMP14]], i64* [[TMP4]], align 8
155; CHECK-NEXT:    [[TMP15:%.*]] = extractelement <4 x i64> [[WIDE_VEC3]], i64 2
156; CHECK-NEXT:    store i64 [[TMP15]], i64* [[TMP5]], align 8
157; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
158; CHECK-NEXT:    [[TMP16:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
159; CHECK-NEXT:    br i1 [[TMP16]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
160; CHECK:       middle.block:
161; CHECK-NEXT:    br label [[SCALAR_PH]]
162; CHECK:       scalar.ph:
163; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
164; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
165; CHECK:       for.body:
166; CHECK-NEXT:    [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[IF_MERGE:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
167; CHECK-NEXT:    [[P_0:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[I]], i32 0
168; CHECK-NEXT:    [[P_1:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[I]], i32 1
169; CHECK-NEXT:    [[TMP17:%.*]] = load i64, i64* [[P_1]], align 8
170; CHECK-NEXT:    [[TMP18:%.*]] = icmp eq i64 [[TMP17]], [[X]]
171; CHECK-NEXT:    br i1 [[TMP18]], label [[IF_THEN:%.*]], label [[IF_MERGE]]
172; CHECK:       if.then:
173; CHECK-NEXT:    store i64 [[TMP17]], i64* [[P_0]], align 8
174; CHECK-NEXT:    br label [[IF_MERGE]]
175; CHECK:       if.merge:
176; CHECK-NEXT:    [[TMP19:%.*]] = load i64, i64* [[P_0]], align 8
177; CHECK-NEXT:    store i64 [[TMP19]], i64* [[P_1]], align 8
178; CHECK-NEXT:    [[I_NEXT]] = add nuw nsw i64 [[I]], 1
179; CHECK-NEXT:    [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
180; CHECK-NEXT:    br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END:%.*]], !llvm.loop [[LOOP5:![0-9]+]]
181; CHECK:       for.end:
182; CHECK-NEXT:    ret void
183;
184entry:
185  br label %for.body
186
187for.body:
188  %i  = phi i64 [ %i.next, %if.merge ], [ 0, %entry ]
189  %p.0 = getelementptr inbounds %pair, %pair* %p, i64 %i, i32 0
190  %p.1 = getelementptr inbounds %pair, %pair* %p, i64 %i, i32 1
191  %0 = load i64, i64* %p.1, align 8
192  %1 = icmp eq i64 %0, %x
193  br i1 %1, label %if.then, label %if.merge
194
195if.then:
196  store i64 %0, i64* %p.0, align 8
197  br label %if.merge
198
199if.merge:
200  %2 = load i64, i64* %p.0, align 8
201  store i64 %2, i64 *%p.1, align 8
202  %i.next = add nuw nsw i64 %i, 1
203  %cond = icmp slt i64 %i.next, %n
204  br i1 %cond, label %for.body, label %for.end
205
206for.end:
207  ret void
208}
209
210; Ensure that we don't create a single interleaved group for the two stores.
211; The second store is conditional and we can't sink the first store inside the
212; predicated block. The load group is vectorized, and the store groups contain
213; gaps and are not vectorized.
214;
215;
216;
217;
218;
219
220define void @interleaved_with_cond_store_2(%pair *%p, i64 %x, i64 %n) {
221; CHECK-LABEL: @interleaved_with_cond_store_2(
222; CHECK-NEXT:  entry:
223; CHECK-NEXT:    [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[N:%.*]], i64 1)
224; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[SMAX]], 3
225; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
226; CHECK:       vector.ph:
227; CHECK-NEXT:    [[N_MOD_VF:%.*]] = and i64 [[SMAX]], 1
228; CHECK-NEXT:    [[TMP0:%.*]] = icmp eq i64 [[N_MOD_VF]], 0
229; CHECK-NEXT:    [[TMP1:%.*]] = select i1 [[TMP0]], i64 2, i64 [[N_MOD_VF]]
230; CHECK-NEXT:    [[N_VEC:%.*]] = sub nsw i64 [[SMAX]], [[TMP1]]
231; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[X:%.*]], i64 0
232; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
233; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
234; CHECK:       vector.body:
235; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[PRED_STORE_CONTINUE2:%.*]] ]
236; CHECK-NEXT:    [[TMP2:%.*]] = or i64 [[INDEX]], 1
237; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds [[PAIR:%.*]], %pair* [[P:%.*]], i64 [[INDEX]], i32 0
238; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[TMP2]], i32 0
239; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[INDEX]], i32 1
240; CHECK-NEXT:    [[TMP6:%.*]] = bitcast i64* [[TMP5]] to <4 x i64>*
241; CHECK-NEXT:    [[WIDE_VEC:%.*]] = load <4 x i64>, <4 x i64>* [[TMP6]], align 8
242; CHECK-NEXT:    [[STRIDED_VEC:%.*]] = shufflevector <4 x i64> [[WIDE_VEC]], <4 x i64> poison, <2 x i32> <i32 0, i32 2>
243; CHECK-NEXT:    store i64 [[X]], i64* [[TMP3]], align 8
244; CHECK-NEXT:    store i64 [[X]], i64* [[TMP4]], align 8
245; CHECK-NEXT:    [[TMP7:%.*]] = icmp eq <2 x i64> [[STRIDED_VEC]], [[BROADCAST_SPLAT]]
246; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x i1> [[TMP7]], i64 0
247; CHECK-NEXT:    br i1 [[TMP8]], label [[PRED_STORE_IF:%.*]], label [[PRED_STORE_CONTINUE:%.*]]
248; CHECK:       pred.store.if:
249; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <4 x i64> [[WIDE_VEC]], i64 0
250; CHECK-NEXT:    store i64 [[TMP9]], i64* [[TMP5]], align 8
251; CHECK-NEXT:    br label [[PRED_STORE_CONTINUE]]
252; CHECK:       pred.store.continue:
253; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <2 x i1> [[TMP7]], i64 1
254; CHECK-NEXT:    br i1 [[TMP10]], label [[PRED_STORE_IF1:%.*]], label [[PRED_STORE_CONTINUE2]]
255; CHECK:       pred.store.if1:
256; CHECK-NEXT:    [[TMP11:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[TMP2]], i32 1
257; CHECK-NEXT:    [[TMP12:%.*]] = extractelement <4 x i64> [[WIDE_VEC]], i64 2
258; CHECK-NEXT:    store i64 [[TMP12]], i64* [[TMP11]], align 8
259; CHECK-NEXT:    br label [[PRED_STORE_CONTINUE2]]
260; CHECK:       pred.store.continue2:
261; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
262; CHECK-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
263; CHECK-NEXT:    br i1 [[TMP13]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
264; CHECK:       middle.block:
265; CHECK-NEXT:    br label [[SCALAR_PH]]
266; CHECK:       scalar.ph:
267; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
268; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
269; CHECK:       for.body:
270; CHECK-NEXT:    [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[IF_MERGE:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
271; CHECK-NEXT:    [[P_0:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[I]], i32 0
272; CHECK-NEXT:    [[P_1:%.*]] = getelementptr inbounds [[PAIR]], %pair* [[P]], i64 [[I]], i32 1
273; CHECK-NEXT:    [[TMP14:%.*]] = load i64, i64* [[P_1]], align 8
274; CHECK-NEXT:    store i64 [[X]], i64* [[P_0]], align 8
275; CHECK-NEXT:    [[TMP15:%.*]] = icmp eq i64 [[TMP14]], [[X]]
276; CHECK-NEXT:    br i1 [[TMP15]], label [[IF_THEN:%.*]], label [[IF_MERGE]]
277; CHECK:       if.then:
278; CHECK-NEXT:    store i64 [[TMP14]], i64* [[P_1]], align 8
279; CHECK-NEXT:    br label [[IF_MERGE]]
280; CHECK:       if.merge:
281; CHECK-NEXT:    [[I_NEXT]] = add nuw nsw i64 [[I]], 1
282; CHECK-NEXT:    [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
283; CHECK-NEXT:    br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END:%.*]], !llvm.loop [[LOOP7:![0-9]+]]
284; CHECK:       for.end:
285; CHECK-NEXT:    ret void
286;
287entry:
288  br label %for.body
289
290for.body:
291  %i  = phi i64 [ %i.next, %if.merge ], [ 0, %entry ]
292  %p.0 = getelementptr inbounds %pair, %pair* %p, i64 %i, i32 0
293  %p.1 = getelementptr inbounds %pair, %pair* %p, i64 %i, i32 1
294  %0 = load i64, i64* %p.1, align 8
295  store i64 %x, i64* %p.0, align 8
296  %1 = icmp eq i64 %0, %x
297  br i1 %1, label %if.then, label %if.merge
298
299if.then:
300  store i64 %0, i64* %p.1, align 8
301  br label %if.merge
302
303if.merge:
304  %i.next = add nuw nsw i64 %i, 1
305  %cond = icmp slt i64 %i.next, %n
306  br i1 %cond, label %for.body, label %for.end
307
308for.end:
309  ret void
310}
311