xref: /llvm-project/llvm/test/Analysis/ScalarEvolution/smin-smax-folds.ll (revision 8b5b294ec2cf876bc5eb5bd5fcb56ef487e36d60)
1; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
2; RUN: opt -disable-output "-passes=print<scalar-evolution>" < %s 2>&1 | FileCheck %s
3
4; Tests for smin & smax folds.
5
6; Test case from PR1614.
7define i32 @test_PR1614(i32 %a, i32 %b, i32 %c) {
8; CHECK-LABEL: 'test_PR1614'
9; CHECK-NEXT:  Classifying expressions for: @test_PR1614
10; CHECK-NEXT:    %B = select i1 %A, i32 %a, i32 %b
11; CHECK-NEXT:    --> (%a smax %b) U: full-set S: full-set
12; CHECK-NEXT:    %D = select i1 %C, i32 %B, i32 %c
13; CHECK-NEXT:    --> (%a smax %b smax %c) U: full-set S: full-set
14; CHECK-NEXT:  Determining loop execution counts for: @test_PR1614
15;
16
17  %A = icmp sgt i32 %a, %b
18  %B = select i1 %A, i32 %a, i32 %b
19  %C = icmp sle i32 %c, %B
20  %D = select i1 %C, i32 %B, i32 %c
21  ret i32 %D
22}
23
24declare void @iteration()
25
26; Test case from PR46939.
27; The information from the loop guard can be used to simplify the trip count expression.
28define void @smin_simplify_with_guard(i32 %n) {
29; CHECK-LABEL: 'smin_simplify_with_guard'
30; CHECK-NEXT:  Classifying expressions for: @smin_simplify_with_guard
31; CHECK-NEXT:    %i.011 = phi i32 [ %n, %for.body.lr.ph ], [ %dec, %for.body ]
32; CHECK-NEXT:    --> {%n,+,-1}<nsw><%for.body> U: full-set S: full-set Exits: 0 LoopDispositions: { %for.body: Computable }
33; CHECK-NEXT:    %dec = add nsw i32 %i.011, -1
34; CHECK-NEXT:    --> {(-1 + %n),+,-1}<nw><%for.body> U: full-set S: full-set Exits: -1 LoopDispositions: { %for.body: Computable }
35; CHECK-NEXT:  Determining loop execution counts for: @smin_simplify_with_guard
36; CHECK-NEXT:  Loop %for.body: backedge-taken count is %n
37; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is i32 2147483647
38; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is %n
39; CHECK-NEXT:  Loop %for.body: Trip multiple is 1
40;
41entry:
42  %cmp10 = icmp sgt i32 %n, -1
43  br i1 %cmp10, label %for.body.lr.ph, label %for.cond.cleanup
44
45for.body.lr.ph:
46  br label %for.body
47
48for.body:
49  %i.011 = phi i32 [ %n, %for.body.lr.ph ], [ %dec, %for.body ]
50  call void @iteration()
51  %dec = add nsw i32 %i.011, -1
52  %cmp = icmp sgt i32 %i.011, 0
53  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
54
55for.cond.cleanup.loopexit:
56  br label %for.cond.cleanup
57
58for.cond.cleanup:
59  ret void
60}
61
62define void @smin_to_smax(i32 %n) {
63; FIXME: ((-1 * (0 smin %n)) + %n)  is actually just  (0 smax %n)
64; CHECK-LABEL: 'smin_to_smax'
65; CHECK-NEXT:  Classifying expressions for: @smin_to_smax
66; CHECK-NEXT:    %i.011 = phi i32 [ %n, %for.body.lr.ph ], [ %dec, %for.body ]
67; CHECK-NEXT:    --> {%n,+,-1}<nsw><%for.body> U: full-set S: full-set Exits: (0 smin %n) LoopDispositions: { %for.body: Computable }
68; CHECK-NEXT:    %dec = add nsw i32 %i.011, -1
69; CHECK-NEXT:    --> {(-1 + %n),+,-1}<nw><%for.body> U: full-set S: full-set Exits: (-1 + (0 smin %n)) LoopDispositions: { %for.body: Computable }
70; CHECK-NEXT:  Determining loop execution counts for: @smin_to_smax
71; CHECK-NEXT:  Loop %for.body: backedge-taken count is ((-1 * (0 smin %n)) + %n)
72; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is i32 2147483647
73; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is ((-1 * (0 smin %n)) + %n)
74; CHECK-NEXT:  Loop %for.body: Trip multiple is 1
75;
76entry:
77  br label %for.body.lr.ph
78
79for.body.lr.ph:
80  br label %for.body
81
82for.body:
83  %i.011 = phi i32 [ %n, %for.body.lr.ph ], [ %dec, %for.body ]
84  call void @iteration()
85  %dec = add nsw i32 %i.011, -1
86  %cmp = icmp sgt i32 %i.011, 0
87  br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
88
89for.cond.cleanup.loopexit:
90  br label %for.cond.cleanup
91
92for.cond.cleanup:
93  ret void
94}
95
96; The information from the loop guard can be used to simplify the trip count expression.
97define void @smax_simplify_with_guard(i32 %start, i32 %n) {
98; CHECK-LABEL: 'smax_simplify_with_guard'
99; CHECK-NEXT:  Classifying expressions for: @smax_simplify_with_guard
100; CHECK-NEXT:    %k.0.i26 = phi i32 [ %start, %loop.ph ], [ %inc.i, %loop ]
101; CHECK-NEXT:    --> {%start,+,1}<nsw><%loop> U: full-set S: full-set Exits: %n LoopDispositions: { %loop: Computable }
102; CHECK-NEXT:    %inc.i = add nsw i32 %k.0.i26, 1
103; CHECK-NEXT:    --> {(1 + %start),+,1}<nw><%loop> U: full-set S: full-set Exits: (1 + %n) LoopDispositions: { %loop: Computable }
104; CHECK-NEXT:  Determining loop execution counts for: @smax_simplify_with_guard
105; CHECK-NEXT:  Loop %loop: backedge-taken count is ((-1 * %start) + %n)
106; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is i32 -1
107; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is ((-1 * %start) + %n)
108; CHECK-NEXT:  Loop %loop: Trip multiple is 1
109;
110entry:
111  %guard = icmp sge i32 %n, %start
112  br i1 %guard, label %loop.ph, label %exit
113
114loop.ph:
115  br label %loop
116
117loop:
118  %k.0.i26 = phi i32 [ %start, %loop.ph ], [ %inc.i, %loop ]
119  %inc.i = add nsw i32 %k.0.i26, 1
120  %cmp26.not.i.not = icmp slt i32 %k.0.i26, %n
121  br i1 %cmp26.not.i.not, label %loop, label %exit
122
123exit:
124  ret void
125}
126