xref: /llvm-project/llvm/test/Transforms/LoopVectorize/ARM/tail-folding-counting-down.ll (revision d486a4c29a331d3bfb3649a8a0aa2ba4970a6455)
1; RUN: opt < %s -passes=loop-vectorize -S | FileCheck %s --check-prefixes=COMMON,DEFAULT
2; RUN: opt < %s -passes=loop-vectorize -tail-predication=enabled -prefer-predicate-over-epilogue=predicate-dont-vectorize -S | FileCheck %s --check-prefixes=COMMON,CHECK-TF,CHECK-PREFER
3; RUN: opt < %s -passes=loop-vectorize -tail-predication=enabled -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue -S | FileCheck %s --check-prefixes=COMMON,CHECK-TF,CHECK-PREFER
4; RUN: opt < %s -passes=loop-vectorize -tail-predication=enabled -S | FileCheck %s --check-prefixes=COMMON,CHECK-TF,CHECK-ENABLE-TP
5
6target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
7target triple = "thumbv8.1m.main-arm-unknown-eabihf"
8
9; This IR corresponds to this type of C-code:
10;
11;  void f(char *a, char *b, char *c, int N) {
12;    while (N-- > 0)
13;      *c++ = *a++ + *b++;
14;  }
15;
16define dso_local void @sgt_loopguard(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
17; COMMON-LABEL: @sgt_loopguard(
18; COMMON:       vector.body:
19
20; CHECK-TF:     %[[VIVELEM0:.*]] = extractelement <16 x i32> %vec.iv, i32 0
21; CHECK-TF:     %active.lane.mask = call <16 x i1> @llvm.get.active.lane.mask.v16i1.i32(i32 %[[VIVELEM0]], i32 %N)
22; CHECK-TF:     llvm.masked.load.v16i8.p0(ptr %{{.*}}, i32 1, <16 x i1> %active.lane.mask
23; CHECK-TF:     llvm.masked.load.v16i8.p0(ptr %{{.*}}, i32 1, <16 x i1> %active.lane.mask
24; CHECK-TF:     llvm.masked.store.v16i8.p0(<16 x i8> %{{.*}}, ptr %{{.*}}, i32 1, <16 x i1> %active.lane.mask)
25entry:
26  %cmp5 = icmp sgt i32 %N, 0
27  br i1 %cmp5, label %while.body.preheader, label %while.end
28
29while.body.preheader:
30  br label %while.body
31
32while.body:
33  %N.addr.09 = phi i32 [ %dec, %while.body ], [ %N, %while.body.preheader ]
34  %c.addr.08 = phi ptr [ %incdec.ptr4, %while.body ], [ %c, %while.body.preheader ]
35  %b.addr.07 = phi ptr [ %incdec.ptr1, %while.body ], [ %b, %while.body.preheader ]
36  %a.addr.06 = phi ptr [ %incdec.ptr, %while.body ], [ %a, %while.body.preheader ]
37  %dec = add nsw i32 %N.addr.09, -1
38  %incdec.ptr = getelementptr inbounds i8, ptr %a.addr.06, i32 1
39  %0 = load i8, ptr %a.addr.06, align 1
40  %incdec.ptr1 = getelementptr inbounds i8, ptr %b.addr.07, i32 1
41  %1 = load i8, ptr %b.addr.07, align 1
42  %add = add i8 %1, %0
43  %incdec.ptr4 = getelementptr inbounds i8, ptr %c.addr.08, i32 1
44  store i8 %add, ptr %c.addr.08, align 1
45  %cmp = icmp sgt i32 %N.addr.09, 1
46  br i1 %cmp, label %while.body, label %while.end.loopexit
47
48while.end.loopexit:
49  br label %while.end
50
51while.end:
52  ret void
53}
54
55; No loop-guard: we need one for this to be valid.
56;
57define dso_local void @sgt_no_loopguard(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
58; COMMON-LABEL: @sgt_no_loopguard(
59; COMMON:       vector.body:
60; CHECK-TF:     masked.load
61; CHECK-TF:     masked.load
62; CHECK-TF:     masked.store
63entry:
64  br label %while.body
65
66while.body:
67  %N.addr.09 = phi i32 [ %dec, %while.body ], [ %N, %entry ]
68  %c.addr.08 = phi ptr [ %incdec.ptr4, %while.body ], [ %c, %entry ]
69  %b.addr.07 = phi ptr [ %incdec.ptr1, %while.body ], [ %b, %entry ]
70  %a.addr.06 = phi ptr [ %incdec.ptr, %while.body ], [ %a, %entry ]
71  %dec = add nsw i32 %N.addr.09, -1
72  %incdec.ptr = getelementptr inbounds i8, ptr %a.addr.06, i32 1
73  %0 = load i8, ptr %a.addr.06, align 1
74  %incdec.ptr1 = getelementptr inbounds i8, ptr %b.addr.07, i32 1
75  %1 = load i8, ptr %b.addr.07, align 1
76  %add = add i8 %1, %0
77  %incdec.ptr4 = getelementptr inbounds i8, ptr %c.addr.08, i32 1
78  store i8 %add, ptr %c.addr.08, align 1
79  %cmp = icmp sgt i32 %N.addr.09, 1
80  br i1 %cmp, label %while.body, label %while.end.loopexit
81
82while.end.loopexit:
83  br label %while.end
84
85while.end:
86  ret void
87}
88
89define dso_local void @sgt_extra_use_cmp(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
90; COMMON-LABEL: @sgt_extra_use_cmp(
91; COMMON:       vector.body:
92; CHECK-TF:     masked.load
93; CHECK-TF:     masked.load
94; CHECK-TF:     masked.store
95entry:
96  br label %while.body
97
98while.body:
99  %N.addr.09 = phi i32 [ %dec, %while.body ], [ %N, %entry ]
100  %c.addr.08 = phi ptr [ %incdec.ptr4, %while.body ], [ %c, %entry ]
101  %b.addr.07 = phi ptr [ %incdec.ptr1, %while.body ], [ %b, %entry ]
102  %a.addr.06 = phi ptr [ %incdec.ptr, %while.body ], [ %a, %entry ]
103  %dec = add nsw i32 %N.addr.09, -1
104  %incdec.ptr = getelementptr inbounds i8, ptr %a.addr.06, i32 1
105  %0 = load i8, ptr %a.addr.06, align 1
106  %incdec.ptr1 = getelementptr inbounds i8, ptr %b.addr.07, i32 1
107  %1 = load i8, ptr %b.addr.07, align 1
108  %add = add i8 %1, %0
109  %incdec.ptr4 = getelementptr inbounds i8, ptr %c.addr.08, i32 1
110  %cmp = icmp sgt i32 %N.addr.09, 1
111  %select = select i1 %cmp, i8 %0, i8 %1
112  %add2 = add i8 %add, %select
113  store i8 %add2, ptr %c.addr.08, align 1
114  br i1 %cmp, label %while.body, label %while.end.loopexit
115
116while.end.loopexit:
117  br label %while.end
118
119while.end:
120  ret void
121}
122
123define dso_local void @sgt_const_tripcount(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
124; COMMON-LABEL: @sgt_const_tripcount(
125; COMMON:       vector.body:
126; CHECK-TF:     masked.load
127; CHECK-TF:     masked.load
128; CHECK-TF:     masked.store
129entry:
130  %cmp5 = icmp sgt i32 %N, 0
131  br i1 %cmp5, label %while.body.preheader, label %while.end
132
133while.body.preheader:
134  br label %while.body
135
136while.body:
137  %N.addr.09 = phi i32 [ %dec, %while.body ], [ 2049, %while.body.preheader ]
138  %c.addr.08 = phi ptr [ %incdec.ptr4, %while.body ], [ %c, %while.body.preheader ]
139  %b.addr.07 = phi ptr [ %incdec.ptr1, %while.body ], [ %b, %while.body.preheader ]
140  %a.addr.06 = phi ptr [ %incdec.ptr, %while.body ], [ %a, %while.body.preheader ]
141  %dec = add nsw i32 %N.addr.09, -1
142  %incdec.ptr = getelementptr inbounds i8, ptr %a.addr.06, i32 1
143  %0 = load i8, ptr %a.addr.06, align 1
144  %incdec.ptr1 = getelementptr inbounds i8, ptr %b.addr.07, i32 1
145  %1 = load i8, ptr %b.addr.07, align 1
146  %add = add i8 %1, %0
147  %incdec.ptr4 = getelementptr inbounds i8, ptr %c.addr.08, i32 1
148  store i8 %add, ptr %c.addr.08, align 1
149  %cmp = icmp sgt i32 %N.addr.09, 1
150  br i1 %cmp, label %while.body, label %while.end.loopexit
151
152while.end.loopexit:
153  br label %while.end
154
155while.end:
156  ret void
157}
158
159define dso_local void @sgt_no_guard_0_startval(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
160; COMMON-LABEL: @sgt_no_guard_0_startval(
161; COMMON-NOT:   vector.body:
162entry:
163  br label %while.body
164
165while.body:
166  %N.addr.09 = phi i32 [ %dec, %while.body ], [ 0, %entry ]
167  %c.addr.08 = phi ptr [ %incdec.ptr4, %while.body ], [ %c, %entry ]
168  %b.addr.07 = phi ptr [ %incdec.ptr1, %while.body ], [ %b, %entry ]
169  %a.addr.06 = phi ptr [ %incdec.ptr, %while.body ], [ %a, %entry]
170  %dec = add nsw i32 %N.addr.09, -1
171  %incdec.ptr = getelementptr inbounds i8, ptr %a.addr.06, i32 1
172  %0 = load i8, ptr %a.addr.06, align 1
173  %incdec.ptr1 = getelementptr inbounds i8, ptr %b.addr.07, i32 1
174  %1 = load i8, ptr %b.addr.07, align 1
175  %add = add i8 %1, %0
176  %incdec.ptr4 = getelementptr inbounds i8, ptr %c.addr.08, i32 1
177  store i8 %add, ptr %c.addr.08, align 1
178  %cmp = icmp sgt i32 %N.addr.09, 1
179  br i1 %cmp, label %while.body, label %while.end.loopexit
180
181while.end.loopexit:
182  br label %while.end
183
184while.end:
185  ret void
186}
187
188define dso_local void @sgt_step_minus_two(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
189; COMMON-LABEL:  @sgt_step_minus_two(
190; COMMON:        vector.body:
191; CHECK-TF:      masked.load
192; CHECK-TF:      masked.load
193; CHECK-TF:      masked.store
194entry:
195  %cmp5 = icmp sgt i32 %N, 0
196  br i1 %cmp5, label %while.body.preheader, label %while.end
197
198while.body.preheader:
199  br label %while.body
200
201while.body:
202  %N.addr.09 = phi i32 [ %dec, %while.body ], [ %N, %while.body.preheader ]
203  %c.addr.08 = phi ptr [ %incdec.ptr4, %while.body ], [ %c, %while.body.preheader ]
204  %b.addr.07 = phi ptr [ %incdec.ptr1, %while.body ], [ %b, %while.body.preheader ]
205  %a.addr.06 = phi ptr [ %incdec.ptr, %while.body ], [ %a, %while.body.preheader ]
206  %dec = add nsw i32 %N.addr.09, -2
207  %incdec.ptr = getelementptr inbounds i8, ptr %a.addr.06, i32 1
208  %0 = load i8, ptr %a.addr.06, align 1
209  %incdec.ptr1 = getelementptr inbounds i8, ptr %b.addr.07, i32 1
210  %1 = load i8, ptr %b.addr.07, align 1
211  %add = add i8 %1, %0
212  %incdec.ptr4 = getelementptr inbounds i8, ptr %c.addr.08, i32 1
213  store i8 %add, ptr %c.addr.08, align 1
214  %cmp = icmp sgt i32 %N.addr.09, 1
215  br i1 %cmp, label %while.body, label %while.end.loopexit
216
217while.end.loopexit:
218  br label %while.end
219
220while.end:
221  ret void
222}
223
224define dso_local void @sgt_step_not_constant(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N, i32 %S) local_unnamed_addr #0 {
225; COMMON-LABEL: @sgt_step_not_constant(
226; COMMON-NOT:   vector.body:
227entry:
228  %cmp5 = icmp sgt i32 %N, 0
229  br i1 %cmp5, label %while.body.preheader, label %while.end
230
231while.body.preheader:
232  br label %while.body
233
234while.body:
235  %N.addr.09 = phi i32 [ %dec, %while.body ], [ %N, %while.body.preheader ]
236  %c.addr.08 = phi ptr [ %incdec.ptr4, %while.body ], [ %c, %while.body.preheader ]
237  %b.addr.07 = phi ptr [ %incdec.ptr1, %while.body ], [ %b, %while.body.preheader ]
238  %a.addr.06 = phi ptr [ %incdec.ptr, %while.body ], [ %a, %while.body.preheader ]
239  %dec = add nsw i32 %N.addr.09, %S
240  %incdec.ptr = getelementptr inbounds i8, ptr %a.addr.06, i32 1
241  %0 = load i8, ptr %a.addr.06, align 1
242  %incdec.ptr1 = getelementptr inbounds i8, ptr %b.addr.07, i32 1
243  %1 = load i8, ptr %b.addr.07, align 1
244  %add = add i8 %1, %0
245  %incdec.ptr4 = getelementptr inbounds i8, ptr %c.addr.08, i32 1
246  store i8 %add, ptr %c.addr.08, align 1
247  %cmp = icmp sgt i32 %N.addr.09, 1
248  br i1 %cmp, label %while.body, label %while.end.loopexit
249
250while.end.loopexit:
251  br label %while.end
252
253while.end:
254  ret void
255}
256
257define dso_local void @icmp_eq(ptr noalias nocapture readonly %A, ptr noalias nocapture readonly %B, ptr noalias nocapture %C, i32 %N) #0 {
258; COMMON-LABEL: @icmp_eq
259; COMMON:       vector.body:
260entry:
261  %cmp6 = icmp eq i32 %N, 0
262  br i1 %cmp6, label %while.end, label %while.body.preheader
263
264while.body.preheader:
265  br label %while.body
266
267while.body:
268  %N.addr.010 = phi i32 [ %dec, %while.body ], [ %N, %while.body.preheader ]
269  %C.addr.09 = phi ptr [ %incdec.ptr4, %while.body ], [ %C, %while.body.preheader ]
270  %B.addr.08 = phi ptr [ %incdec.ptr1, %while.body ], [ %B, %while.body.preheader ]
271  %A.addr.07 = phi ptr [ %incdec.ptr, %while.body ], [ %A, %while.body.preheader ]
272  %incdec.ptr = getelementptr inbounds i8, ptr %A.addr.07, i32 1
273  %0 = load i8, ptr %A.addr.07, align 1
274  %incdec.ptr1 = getelementptr inbounds i8, ptr %B.addr.08, i32 1
275  %1 = load i8, ptr %B.addr.08, align 1
276  %add = add i8 %1, %0
277  %incdec.ptr4 = getelementptr inbounds i8, ptr %C.addr.09, i32 1
278  store i8 %add, ptr %C.addr.09, align 1
279  %dec = add i32 %N.addr.010, -1
280  %cmp = icmp eq i32 %dec, 0
281  br i1 %cmp, label %while.end.loopexit, label %while.body
282
283while.end.loopexit:
284  br label %while.end
285
286while.end:
287  ret void
288}
289
290; This IR corresponds to this type of C-code:
291;
292;  void f(char *a, char *b, char * __restrict c, int N) {
293;    #pragma clang loop vectorize_width(16)
294;    for (int i = N; i>0; i--)
295;      c[i] = a[i] + b[i];
296;  }
297;
298define dso_local void @sgt_for_loop(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
299; COMMON-LABEL: @sgt_for_loop(
300; COMMON:       vector.body:
301; CHECK-PREFER: masked.load
302; CHECK-PREFER: masked.load
303; CHECK-PREFER: masked.store
304;
305; TODO: if tail-predication is requested, tail-folding isn't triggered because
306; the profitability check returns "Different strides found, can't tail-predicate",
307; investigate this.
308;
309; CHECK-ENABLE-TP-NOT: masked.load
310; CHECK-ENABLE-TP-NOT: masked.load
311; CHECK-ENABLE-TP-NOT: masked.store
312;
313entry:
314  %cmp5 = icmp sgt i32 %N, 0
315  br i1 %cmp5, label %for.body.preheader, label %for.end
316
317for.body.preheader:
318  br label %for.body
319
320for.body:
321  %i.011 = phi i32 [ %dec, %for.body ], [ %N, %for.body.preheader ]
322  %arrayidx = getelementptr inbounds i8, ptr %a, i32 %i.011
323  %0 = load i8, ptr %arrayidx, align 1
324  %arrayidx1 = getelementptr inbounds i8, ptr %b, i32 %i.011
325  %1 = load i8, ptr %arrayidx1, align 1
326  %add = add i8 %1, %0
327  %arrayidx4 = getelementptr inbounds i8, ptr %c, i32 %i.011
328  store i8 %add, ptr %arrayidx4, align 1
329  %dec = add nsw i32 %i.011, -1
330  %cmp = icmp sgt i32 %i.011, 1
331  br i1 %cmp, label %for.body, label %for.end, !llvm.loop !1
332
333for.end:
334  ret void
335}
336
337define dso_local void @sgt_for_loop_i64(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
338; COMMON-LABEL: @sgt_for_loop_i64(
339; COMMON:       vector.body:
340;
341; CHECK-PREFER: masked.load
342; CHECK-PREFER: masked.load
343; CHECK-PREFER: masked.store
344;
345; With -disable-mve-tail-predication=false, the target hook returns
346; "preferPredicateOverEpilogue: hardware-loop is not profitable."
347; so here we don't expect the tail-folding. TODO: look into this.
348;
349; CHECK-ENABLE-TP-NOT:  masked.load
350; CHECK-ENABLE-TP-NOT:  masked.load
351; CHECK-ENABLE-TP-NOT:  masked.store
352;
353entry:
354  %cmp14 = icmp sgt i32 %N, 0
355  br i1 %cmp14, label %for.body.preheader, label %for.cond.cleanup
356
357for.body.preheader:
358  %conv16 = zext i32 %N to i64
359  br label %for.body
360
361for.cond.cleanup.loopexit:
362  br label %for.cond.cleanup
363
364for.cond.cleanup:
365  ret void
366
367for.body:
368  %i.015 = phi i64 [ %dec, %for.body ], [ %conv16, %for.body.preheader ]
369  %idxprom = trunc i64 %i.015 to i32
370  %arrayidx = getelementptr inbounds i8, ptr %a, i32 %idxprom
371  %0 = load i8, ptr %arrayidx, align 1
372  %arrayidx4 = getelementptr inbounds i8, ptr %b, i32 %idxprom
373  %1 = load i8, ptr %arrayidx4, align 1
374  %add = add i8 %1, %0
375  %arrayidx8 = getelementptr inbounds i8, ptr %c, i32 %idxprom
376  store i8 %add, ptr %arrayidx8, align 1
377  %dec = add nsw i64 %i.015, -1
378  %cmp = icmp sgt i64 %i.015, 1
379  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit, !llvm.loop !1
380}
381
382; This IR corresponds to this nested-loop:
383;
384;   for (int i = 0; i<N; i++)
385;     for (int j = i+1; j>0; j--)
386;       c[j] = a[j] + b[j];
387;
388; while the inner-loop looks similar to previous examples, we can't
389; transform this because the inner loop because isGuarded returns
390; false for the inner-loop.
391;
392define dso_local void @sgt_nested_loop(ptr noalias nocapture readonly %a, ptr noalias nocapture readonly %b, ptr noalias nocapture %c, i32 %N) local_unnamed_addr #0 {
393; COMMON-LABEL: @sgt_nested_loop(
394; DEFAULT-NOT:  vector.body:
395; CHECK-TF-NOT: masked.load
396; CHECK-TF-NOT: masked.load
397; CHECK-TF-NOT: masked.store
398; COMMON:       }
399;
400entry:
401  %cmp21 = icmp sgt i32 %N, 0
402  br i1 %cmp21, label %for.body.preheader, label %for.cond.cleanup
403
404for.body.preheader:
405  br label %for.body
406
407for.cond.loopexit:
408  %exitcond = icmp eq i32 %add, %N
409  br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body
410
411for.cond.cleanup.loopexit:
412  br label %for.cond.cleanup
413
414for.cond.cleanup:
415  ret void
416
417for.body:
418  %i.022 = phi i32 [ %add, %for.cond.loopexit ], [ 0, %for.body.preheader ]
419  %add = add nuw nsw i32 %i.022, 1
420  br label %for.body4
421
422for.body4:                                        ; preds = %for.body, %for.body4
423  %j.020 = phi i32 [ %add, %for.body ], [ %dec, %for.body4 ]
424  %arrayidx = getelementptr inbounds i8, ptr %a, i32 %j.020
425  %0 = load i8, ptr %arrayidx, align 1
426  %arrayidx5 = getelementptr inbounds i8, ptr %b, i32 %j.020
427  %1 = load i8, ptr %arrayidx5, align 1
428  %add7 = add i8 %1, %0
429  %arrayidx9 = getelementptr inbounds i8, ptr %c, i32 %j.020
430  store i8 %add7, ptr %arrayidx9, align 1
431  %dec = add nsw i32 %j.020, -1
432  %cmp2 = icmp sgt i32 %j.020, 1
433  br i1 %cmp2, label %for.body4, label %for.cond.loopexit
434}
435
436attributes #0 = { nofree norecurse nounwind "target-features"="+armv8.1-m.main,+mve.fp" }
437
438!1 = distinct !{!1, !2}
439!2 = !{!"llvm.loop.vectorize.width", i32 16}
440