xref: /llvm-project/llvm/test/Analysis/MustExecute/const-cond.ll (revision 05a97a1a5143d0af60f2dc1e452c3f4ab7409b4c)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; RUN: opt -disable-output -passes=print-mustexecute %s 2>&1 | FileCheck %s
3
4; In general the CFG below is easily simplified but this is useful for
5; pass ordering issue elimination.
6define i1 @const_cond(i32 %high) {
7; CHECK-LABEL: @const_cond(
8; CHECK-NEXT:  entry:
9; CHECK-NEXT:    br label [[LOOP:%.*]]
10; CHECK:       loop:
11; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ] ; (mustexec in: loop)
12; CHECK-NEXT:    br i1 true, label [[NEXT:%.*]], label [[NEVER1:%.*]] ; (mustexec in: loop)
13; CHECK:       next:
14; CHECK-NEXT:    br i1 false, label [[NEVER2:%.*]], label [[BACKEDGE]] ; (mustexec in: loop)
15; CHECK:       backedge:
16; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i32 [[IV]], 1 ; (mustexec in: loop)
17; CHECK-NEXT:    [[EXIT_TEST:%.*]] = icmp slt i32 [[IV]], [[HIGH:%.*]] ; (mustexec in: loop)
18; CHECK-NEXT:    br i1 [[EXIT_TEST]], label [[LOOP]], label [[EXIT:%.*]] ; (mustexec in: loop)
19; CHECK:       exit:
20; CHECK-NEXT:    ret i1 false
21; CHECK:       never1:
22; CHECK-NEXT:    unreachable
23; CHECK:       never2:
24; CHECK-NEXT:    unreachable
25;
26entry:
27  br label %loop
28
29loop:
30  %iv = phi i32 [0, %entry], [%iv.next, %backedge]
31  br i1 true, label %next, label %never1
32next:
33  br i1 false, label %never2, label %backedge
34backedge:
35  %iv.next = add nsw nuw i32 %iv, 1
36  %exit.test = icmp slt i32 %iv, %high
37  br i1 %exit.test, label %loop, label %exit
38
39exit:
40  ret i1 false
41never1:
42  unreachable
43never2:
44  unreachable
45}
46
47