1; RUN: opt < %s -indvars -S | FileCheck %s
2;
3; Make sure that indvars can perform LFTR without a canonical IV.
4
5target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
6
7; Perform LFTR using the original pointer-type IV.
8
9;  for(char* p = base; p < base + n; ++p) {
10;    *p = p-base;
11;  }
12define void @ptriv(i8* %base, i32 %n) nounwind {
13entry:
14  %idx.ext = sext i32 %n to i64
15  %add.ptr = getelementptr inbounds i8* %base, i64 %idx.ext
16  %cmp1 = icmp ult i8* %base, %add.ptr
17  br i1 %cmp1, label %for.body, label %for.end
18
19; CHECK: for.body:
20; CHECK: phi i8*
21; CHECK-NOT: phi
22; CHECK-NOT: add
23; CHECK: icmp ne i8*
24; CHECK: br i1
25for.body:
26  %p.02 = phi i8* [ %base, %entry ], [ %incdec.ptr, %for.body ]
27  ; cruft to make the IV useful
28  %sub.ptr.lhs.cast = ptrtoint i8* %p.02 to i64
29  %sub.ptr.rhs.cast = ptrtoint i8* %base to i64
30  %sub.ptr.sub = sub i64 %sub.ptr.lhs.cast, %sub.ptr.rhs.cast
31  %conv = trunc i64 %sub.ptr.sub to i8
32  store i8 %conv, i8* %p.02
33  %incdec.ptr = getelementptr inbounds i8* %p.02, i32 1
34  %cmp = icmp ult i8* %incdec.ptr, %add.ptr
35  br i1 %cmp, label %for.body, label %for.end
36
37for.end:
38  ret void
39}
40
41; It would be nice if SCEV and any loop analysis could assume that
42; preheaders exist. Unfortunately it is not always the case. This test
43; checks that SCEVExpander can handle an outer loop that has not yet
44; been simplified. As a result, the inner loop's exit test will not be
45; rewritten.
46define void @expandOuterRecurrence(i32 %arg) nounwind {
47entry:
48  %sub1 = sub nsw i32 %arg, 1
49  %cmp1 = icmp slt i32 0, %sub1
50  br i1 %cmp1, label %outer, label %exit
51
52outer:
53  %i = phi i32 [ 0, %entry ], [ %i.inc, %outer.inc ]
54  %sub2 = sub nsw i32 %arg, %i
55  %sub3 = sub nsw i32 %sub2, 1
56  %cmp2 = icmp slt i32 0, %sub3
57  br i1 %cmp2, label %inner.ph, label %outer.inc
58
59inner.ph:
60  br label %inner
61
62; CHECK: inner:
63; CHECK: icmp slt
64; CHECK: br i1
65inner:
66  %j = phi i32 [ 0, %inner.ph ], [ %j.inc, %inner ]
67  %j.inc = add nsw i32 %j, 1
68  %cmp3 = icmp slt i32 %j.inc, %sub3
69  br i1 %cmp3, label %inner, label %outer.inc
70
71; CHECK: outer.inc:
72; CHECK: icmp ne
73; CHECK: br i1
74outer.inc:
75  %i.inc = add nsw i32 %i, 1
76  %cmp4 = icmp slt i32 %i.inc, %sub1
77  br i1 %cmp4, label %outer, label %exit
78
79exit:
80  ret void
81}
82
83; Force SCEVExpander to look for an existing well-formed phi.
84; Perform LFTR without generating extra preheader code.
85define void @guardedloop([0 x double]* %matrix, [0 x double]* %vector,
86                         i32 %irow, i32 %ilead) nounwind {
87; CHECK: entry:
88; CHECK-NOT: zext
89; CHECK-NOT: add
90; CHECK: loop:
91; CHECK: phi i64
92; CHECK: phi i64
93; CHECK-NOT: phi
94; CHECK: icmp ne
95; CHECK: br i1
96entry:
97  %cmp = icmp slt i32 1, %irow
98  br i1 %cmp, label %loop, label %return
99
100loop:
101  %rowidx = phi i32 [ 0, %entry ], [ %row.inc, %loop ]
102  %i = phi i32 [ 0, %entry ], [ %i.inc, %loop ]
103  %diagidx = add nsw i32 %rowidx, %i
104  %diagidxw = sext i32 %diagidx to i64
105  %matrixp = getelementptr inbounds [0 x double]* %matrix, i32 0, i64 %diagidxw
106  %v1 = load double* %matrixp
107  %iw = sext i32 %i to i64
108  %vectorp = getelementptr inbounds [0 x double]* %vector, i32 0, i64 %iw
109  %v2 = load double* %vectorp
110  %row.inc = add nsw i32 %rowidx, %ilead
111  %i.inc = add nsw i32 %i, 1
112  %cmp196 = icmp slt i32 %i.inc, %irow
113  br i1 %cmp196, label %loop, label %return
114
115return:
116  ret void
117}
118
119; Avoid generating extra code to materialize a trip count. Skip LFTR.
120define void @unguardedloop([0 x double]* %matrix, [0 x double]* %vector,
121                           i32 %irow, i32 %ilead) nounwind {
122entry:
123  br label %loop
124
125; CHECK: entry:
126; CHECK-NOT: zext
127; CHECK-NOT: add
128; CHECK: loop:
129; CHECK: phi i64
130; CHECK: phi i64
131; CHECK-NOT: phi
132; CHECK: icmp slt
133; CHECK: br i1
134loop:
135  %rowidx = phi i32 [ 0, %entry ], [ %row.inc, %loop ]
136  %i = phi i32 [ 0, %entry ], [ %i.inc, %loop ]
137  %diagidx = add nsw i32 %rowidx, %i
138  %diagidxw = sext i32 %diagidx to i64
139  %matrixp = getelementptr inbounds [0 x double]* %matrix, i32 0, i64 %diagidxw
140  %v1 = load double* %matrixp
141  %iw = sext i32 %i to i64
142  %vectorp = getelementptr inbounds [0 x double]* %vector, i32 0, i64 %iw
143  %v2 = load double* %vectorp
144  %row.inc = add nsw i32 %rowidx, %ilead
145  %i.inc = add nsw i32 %i, 1
146  %cmp196 = icmp slt i32 %i.inc, %irow
147  br i1 %cmp196, label %loop, label %return
148
149return:
150  ret void
151}
152
153; Remove %i which is only used by the exit test.
154; Verify that SCEV can still compute a backedge count from the sign
155; extended %n, used for pointer comparison by LFTR.
156;
157; TODO: Fix for PR13371 currently makes this impossible. See
158; IndVarSimplify.cpp hasConcreteDef(). We may want to change to undef rules.
159define void @geplftr(i8* %base, i32 %x, i32 %y, i32 %n) nounwind {
160entry:
161  %x.ext = sext i32 %x to i64
162  %add.ptr = getelementptr inbounds i8* %base, i64 %x.ext
163  %y.ext = sext i32 %y to i64
164  %add.ptr10 = getelementptr inbounds i8* %add.ptr, i64 %y.ext
165  %lim = add i32 %x, %n
166  %cmp.ph = icmp ult i32 %x, %lim
167  br i1 %cmp.ph, label %loop, label %exit
168; CHECK-LABEL: @geplftr(
169; CHECK: loop:
170; CHECK: phi i8*
171; DISABLE-NOT: phi      // This check is currently disabled
172; CHECK: getelementptr
173; CHECK: store
174; DISABLE: icmp ne i8*  // This check is currently disabled
175; CHECK: br i1
176loop:
177  %i = phi i32 [ %x, %entry ], [ %inc, %loop ]
178  %aptr = phi i8* [ %add.ptr10, %entry ], [ %incdec.ptr, %loop ]
179  %incdec.ptr = getelementptr inbounds i8* %aptr, i32 1
180  store i8 3, i8* %aptr
181  %inc = add i32 %i, 1
182  %cmp = icmp ult i32 %inc, %lim
183  br i1 %cmp, label %loop, label %exit
184
185exit:
186  ret void
187}
188
189; Exercise backedge taken count verification with a never-taken loop.
190define void @nevertaken() nounwind uwtable ssp {
191entry:
192  br label %loop
193; CHECK-LABEL: @nevertaken(
194; CHECK: loop:
195; CHECK-NOT: phi
196; CHECK-NOT: add
197; CHECK-NOT: icmp
198; CHECK: exit:
199loop:
200  %i = phi i32 [ 0, %entry ], [ %inc, %loop ]
201  %inc = add nsw i32 %i, 1
202  %cmp = icmp sle i32 %inc, 0
203  br i1 %cmp, label %loop, label %exit
204
205exit:
206  ret void
207}
208
209; Test LFTR on an IV whose recurrence start is a non-unit pointer type.
210define void @aryptriv([256 x i8]* %base, i32 %n) nounwind {
211entry:
212  %ivstart = getelementptr inbounds [256 x i8]* %base, i32 0, i32 0
213  %ivend = getelementptr inbounds [256 x i8]* %base, i32 0, i32 %n
214  %cmp.ph = icmp ult i8* %ivstart, %ivend
215  br i1 %cmp.ph, label %loop, label %exit
216
217; CHECK: loop:
218; CHECK: phi i8*
219; CHECK-NOT: phi
220; CHECK: getelementptr
221; CHECK: store
222; CHECK: icmp ne i8*
223; CHECK: br i1
224loop:
225  %aptr = phi i8* [ %ivstart, %entry ], [ %incdec.ptr, %loop ]
226  %incdec.ptr = getelementptr inbounds i8* %aptr, i32 1
227  store i8 3, i8* %aptr
228  %cmp = icmp ult i8* %incdec.ptr, %ivend
229  br i1 %cmp, label %loop, label %exit
230
231exit:
232  ret void
233}
234