1; RUN: opt < %s -loop-unswitch -enable-new-pm=0 -loop-unswitch-threshold=0 -verify-loop-info -S < %s 2>&1 | FileCheck %s
2; RUN: opt < %s -loop-unswitch -enable-new-pm=0 -loop-unswitch-threshold=0 -verify-loop-info -enable-mssa-loop-dependency=true -verify-memoryssa -S < %s 2>&1 | FileCheck %s
3
4; This test contains two trivial unswitch condition in one loop.
5; LoopUnswitch pass should be able to unswitch the second one
6; after unswitching the first one.
7
8
9; CHECK:  br i1 %cond1, label %..split_crit_edge, label %.loop_exit.split_crit_edge
10
11; CHECK:  ..split_crit_edge:                                ; preds = %0
12; CHECK:    br label %.split
13
14; CHECK:  .split:                                           ; preds = %..split_crit_edge
15; CHECK:    br i1 %cond2, label %.split..split.split_crit_edge, label %.split.loop_exit.split1_crit_edge
16
17; CHECK:  .split..split.split_crit_edge:                    ; preds = %.split
18; CHECK:    br label %.split.split
19
20; CHECK:  .split.split:                                     ; preds = %.split..split.split_crit_edge
21; CHECK:    br label %loop_begin
22
23; CHECK:  loop_begin:                                       ; preds = %do_something, %.split.split
24; CHECK:    br i1 true, label %continue, label %loop_exit
25
26; CHECK:  continue:                                         ; preds = %loop_begin
27; CHECK:    %var_val = load i32, i32* %var
28; CHECK:    br i1 true, label %do_something, label %loop_exit
29
30define i32 @test(i32* %var, i1 %cond1, i1 %cond2) {
31  br label %loop_begin
32
33loop_begin:
34  br i1 %cond1, label %continue, label %loop_exit	; first trivial condition
35
36continue:
37  %var_val = load i32, i32* %var
38  br i1 %cond2, label %do_something, label %loop_exit	; second trivial condition
39
40do_something:
41  call void @some_func() noreturn nounwind
42  br label %loop_begin
43
44loop_exit:
45  ret i32 0
46}
47
48
49; We will not be able trivially unswitch on the SwitchInst, as its input
50; is a constant. However, since its a constant we should be able to figure
51; out that the switch can be folded into a unconditional branch to %continue.
52; Then we unswitch on the br inst in %continue.
53;
54; CHECK: define i32 @test2(
55; This is an indication that the loop has been unswitched on %cond1.
56; CHECK:  br i1 %cond1, label %..split_crit_edge, label %.loop_exit.split_crit_edge
57
58; CHECK:  ..split_crit_edge:                                ; preds = %0
59; CHECK:    br label %.split
60
61; CHECK:  .split:                                           ; preds = %..split_crit_edge
62; CHECK:    br label %loop_begin
63
64; CHECK:  loop_begin:                                       ; preds = %do_something, %.split
65; CHECK:    switch i32
66
67; CHECK:  continue:                                         ; preds = %loop_begin
68; CHECK:    %var_val = load i32, i32* %var
69; CHECK:    br i1 true, label %do_something, label %loop_exit
70
71define i32 @test2(i32* %var, i1 %cond1) {
72  br label %loop_begin
73
74loop_begin:
75  switch i32 1, label %continue [
76    i32 0, label %loop_exit
77    i32 1, label %continue
78  ]
79
80continue:
81  %var_val = load i32, i32* %var
82  br i1 %cond1, label %do_something, label %loop_exit
83
84do_something:
85  call void @some_func() noreturn nounwind
86  br label %loop_begin
87
88loop_exit:
89  ret i32 0
90}
91
92declare void @some_func() noreturn
93