1; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
2
3; ScalarEvolution should be able to understand the loop and eliminate the casts.
4
5; CHECK: {%d,+,4}
6
7define void @foo(i32* nocapture %d, i32 %n) nounwind {
8entry:
9	%0 = icmp sgt i32 %n, 0		; <i1> [#uses=1]
10	br i1 %0, label %bb.nph, label %return
11
12bb.nph:		; preds = %entry
13	br label %bb
14
15bb:		; preds = %bb1, %bb.nph
16	%i.02 = phi i32 [ %5, %bb1 ], [ 0, %bb.nph ]		; <i32> [#uses=2]
17	%p.01 = phi i8 [ %4, %bb1 ], [ -1, %bb.nph ]		; <i8> [#uses=2]
18	%1 = sext i8 %p.01 to i32		; <i32> [#uses=1]
19	%2 = sext i32 %i.02 to i64		; <i64> [#uses=1]
20	%3 = getelementptr i32, i32* %d, i64 %2		; <i32*> [#uses=1]
21	store i32 %1, i32* %3, align 4
22	%4 = add i8 %p.01, 1		; <i8> [#uses=1]
23	%5 = add i32 %i.02, 1		; <i32> [#uses=2]
24	br label %bb1
25
26bb1:		; preds = %bb
27	%6 = icmp slt i32 %5, %n		; <i1> [#uses=1]
28	br i1 %6, label %bb, label %bb1.return_crit_edge
29
30bb1.return_crit_edge:		; preds = %bb1
31	br label %return
32
33return:		; preds = %bb1.return_crit_edge, %entry
34	ret void
35}
36
37; ScalarEvolution should be able to find the maximum tripcount
38; of this multiple-exit loop, and if it doesn't know the exact
39; count, it should say so.
40
41; PR7845
42; CHECK: Loop %for.cond: <multiple exits> Unpredictable backedge-taken count.
43; CHECK: Loop %for.cond: max backedge-taken count is 5
44
45@.str = private constant [4 x i8] c"%d\0A\00"     ; <[4 x i8]*> [#uses=2]
46
47define i32 @main() nounwind {
48entry:
49  br label %for.cond
50
51for.cond:                                         ; preds = %for.inc, %entry
52  %g_4.0 = phi i32 [ 0, %entry ], [ %add, %for.inc ] ; <i32> [#uses=5]
53  %cmp = icmp slt i32 %g_4.0, 5                   ; <i1> [#uses=1]
54  br i1 %cmp, label %for.body, label %for.end
55
56for.body:                                         ; preds = %for.cond
57  %conv = trunc i32 %g_4.0 to i16                 ; <i16> [#uses=1]
58  %tobool.not = icmp eq i16 %conv, 0              ; <i1> [#uses=1]
59  %tobool3 = icmp ne i32 %g_4.0, 0                ; <i1> [#uses=1]
60  %or.cond = and i1 %tobool.not, %tobool3         ; <i1> [#uses=1]
61  br i1 %or.cond, label %for.end, label %for.inc
62
63for.inc:                                          ; preds = %for.body
64  %add = add nsw i32 %g_4.0, 1                    ; <i32> [#uses=1]
65  br label %for.cond
66
67for.end:                                          ; preds = %for.body, %for.cond
68  %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i32 %g_4.0) nounwind ; <i32> [#uses=0]
69  ret i32 0
70}
71
72declare i32 @printf(i8*, ...)
73
74define void @test(i8* %a, i32 %n) nounwind {
75entry:
76  %cmp1 = icmp sgt i32 %n, 0
77  br i1 %cmp1, label %for.body.lr.ph, label %for.end
78
79for.body.lr.ph:                                   ; preds = %entry
80  %tmp = zext i32 %n to i64
81  br label %for.body
82
83for.body:                                         ; preds = %for.body, %for.body.lr.ph
84  %indvar = phi i64 [ %indvar.next, %for.body ], [ 0, %for.body.lr.ph ]
85  %arrayidx = getelementptr i8, i8* %a, i64 %indvar
86  store i8 0, i8* %arrayidx, align 1
87  %indvar.next = add i64 %indvar, 1
88  %exitcond = icmp ne i64 %indvar.next, %tmp
89  br i1 %exitcond, label %for.body, label %for.cond.for.end_crit_edge
90
91for.cond.for.end_crit_edge:                       ; preds = %for.body
92  br label %for.end
93
94for.end:                                          ; preds = %for.cond.for.end_crit_edge, %entry
95  ret void
96}
97
98; CHECK: Determining loop execution counts for: @test
99; CHECK-NEXT: backedge-taken count is
100; CHECK-NEXT: max backedge-taken count is -1
101
102; PR19799: Indvars miscompile due to an incorrect max backedge taken count from SCEV.
103; CHECK-LABEL: @pr19799
104; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count.
105; CHECK: Loop %for.body.i: max backedge-taken count is 1
106@a = common global i32 0, align 4
107
108define i32 @pr19799() {
109entry:
110  store i32 -1, i32* @a, align 4
111  br label %for.body.i
112
113for.body.i:                                       ; preds = %for.cond.i, %entry
114  %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
115  %tobool.i = icmp eq i32 %storemerge1.i, 0
116  %add.i.i = add nsw i32 %storemerge1.i, 2
117  br i1 %tobool.i, label %bar.exit, label %for.cond.i
118
119for.cond.i:                                       ; preds = %for.body.i
120  store i32 %add.i.i, i32* @a, align 4
121  %cmp.i = icmp slt i32 %storemerge1.i, 0
122  br i1 %cmp.i, label %for.body.i, label %bar.exit
123
124bar.exit:                                         ; preds = %for.cond.i, %for.body.i
125  ret i32 0
126}
127
128; PR18886: Indvars miscompile due to an incorrect max backedge taken count from SCEV.
129; CHECK-LABEL: @pr18886
130; CHECK: Loop %for.body: <multiple exits> Unpredictable backedge-taken count.
131; CHECK: Loop %for.body: max backedge-taken count is 3
132@aa = global i64 0, align 8
133
134define i32 @pr18886() {
135entry:
136  store i64 -21, i64* @aa, align 8
137  br label %for.body
138
139for.body:
140  %storemerge1 = phi i64 [ -21, %entry ], [ %add, %for.cond ]
141  %tobool = icmp eq i64 %storemerge1, 0
142  %add = add nsw i64 %storemerge1, 8
143  br i1 %tobool, label %return, label %for.cond
144
145for.cond:
146  store i64 %add, i64* @aa, align 8
147  %cmp = icmp slt i64 %add, 9
148  br i1 %cmp, label %for.body, label %return
149
150return:
151  %retval.0 = phi i32 [ 1, %for.body ], [ 0, %for.cond ]
152  ret i32 %retval.0
153}
154
155; Here we have a must-exit loop latch that is not computable and a
156; may-exit early exit that can only have one non-exiting iteration
157; before the check is forever skipped.
158;
159; CHECK-LABEL: @cannot_compute_mustexit
160; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count.
161; CHECK: Loop %for.body.i: Unpredictable max backedge-taken count.
162@b = common global i32 0, align 4
163
164define i32 @cannot_compute_mustexit() {
165entry:
166  store i32 -1, i32* @a, align 4
167  br label %for.body.i
168
169for.body.i:                                       ; preds = %for.cond.i, %entry
170  %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
171  %tobool.i = icmp eq i32 %storemerge1.i, 0
172  %add.i.i = add nsw i32 %storemerge1.i, 2
173  br i1 %tobool.i, label %bar.exit, label %for.cond.i
174
175for.cond.i:                                       ; preds = %for.body.i
176  store i32 %add.i.i, i32* @a, align 4
177  %ld = load volatile i32, i32* @b
178  %cmp.i = icmp ne i32 %ld, 0
179  br i1 %cmp.i, label %for.body.i, label %bar.exit
180
181bar.exit:                                         ; preds = %for.cond.i, %for.body.i
182  ret i32 0
183}
184
185; This loop has two must-exits, both of which dominate the latch. The
186; MaxBECount should be the minimum of them.
187;
188; CHECK-LABEL: @two_mustexit
189; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count.
190; CHECK: Loop %for.body.i: max backedge-taken count is 1
191define i32 @two_mustexit() {
192entry:
193  store i32 -1, i32* @a, align 4
194  br label %for.body.i
195
196for.body.i:                                       ; preds = %for.cond.i, %entry
197  %storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
198  %tobool.i = icmp sgt i32 %storemerge1.i, 0
199  %add.i.i = add nsw i32 %storemerge1.i, 2
200  br i1 %tobool.i, label %bar.exit, label %for.cond.i
201
202for.cond.i:                                       ; preds = %for.body.i
203  store i32 %add.i.i, i32* @a, align 4
204  %cmp.i = icmp slt i32 %storemerge1.i, 3
205  br i1 %cmp.i, label %for.body.i, label %bar.exit
206
207bar.exit:                                         ; preds = %for.cond.i, %for.body.i
208  ret i32 0
209}
210