1; RUN: llc < %s -asm-verbose=false -verify-machineinstrs | FileCheck %s
2
3;; Test that a small but nontrivial switch in a loop (like in a
4;; bytecode interpreter) lowers reasonably without any irreducible
5;; control flow being introduced.
6
7target triple = "wasm32"
8
9declare void @a(i32*)
10declare void @b(i32*)
11
12; CHECK-LABEL: switch_in_loop:
13; CHECK-NEXT: .functype switch_in_loop (i32, i32) -> (i32)
14; CHECK:    global.get __stack_pointer
15; CHECK:    global.set __stack_pointer
16; CHECK:    block
17; CHECK:    br_if 0
18; CHECK: .LBB0_2:
19; CHECK:    loop
20; CHECK:    block
21; CHECK:    block
22; CHECK:    block
23; CHECK:    br_table {0, 1, 2}
24; CHECK: .LBB0_3:
25; CHECK:    end_block
26; CHECK:    call a
27; CHECK:    br 1
28; CHECK: .LBB0_4:
29; CHECK:    end_block
30; CHECK:    call b
31; CHECK: .LBB0_5:
32; CHECK:    end_block
33; CHECK:    br_if 0
34; CHECK:    end_loop
35; CHECK: .LBB0_7:
36; CHECK:    end_block
37; CHECK:    global.set __stack_pointer
38; CHECK:    end_function
39define i32 @switch_in_loop(i32* %ops, i32 %len) {
40entry:
41  %res = alloca i32
42  %0 = bitcast i32* %res to i8*
43  store i32 0, i32* %res
44  %cmp6 = icmp sgt i32 %len, 0
45  br i1 %cmp6, label %for.body, label %for.cond.cleanup
46
47for.cond.cleanup.loopexit:                        ; preds = %sw.epilog
48  %.pre = load i32, i32* %res
49  br label %for.cond.cleanup
50
51for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
52  %1 = phi i32 [ %.pre, %for.cond.cleanup.loopexit ], [ 0, %entry ]
53  ret i32 %1
54
55for.body:                                         ; preds = %entry, %sw.epilog
56  %i.07 = phi i32 [ %inc, %sw.epilog ], [ 0, %entry ]
57  %arrayidx = getelementptr inbounds i32, i32* %ops, i32 %i.07
58  %2 = load i32, i32* %arrayidx
59  switch i32 %2, label %sw.epilog [
60    i32 0, label %sw.bb
61    i32 1, label %sw.bb1
62  ]
63
64sw.bb:                                            ; preds = %for.body
65  call void @a(i32* nonnull %res)
66  br label %sw.epilog
67
68sw.bb1:                                           ; preds = %for.body
69  call void @b(i32* nonnull %res)
70  br label %sw.epilog
71
72sw.epilog:                                        ; preds = %for.body, %sw.bb1, %sw.bb
73  %inc = add nuw nsw i32 %i.07, 1
74  %exitcond = icmp eq i32 %inc, %len
75  br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body
76}
77