xref: /llvm-project/llvm/test/Transforms/SimplifyCFG/switch-to-select-multiple-edge-per-block-phi.ll (revision 8979ae42769e529b0f6fce3268492ffb49bd54b9)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; RUN: opt < %s -passes=simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
3
4; a, b;
5; fn1() {
6;   if (b)
7;     if (a == 0 || a == 5)
8;       return a;
9;   return 0;
10; }
11
12; Checking that we handle correctly the case when we have a switch
13; branching multiple times to the same block
14
15@b = common global i32 0, align 4
16@a = common global i32 0, align 4
17
18; Function Attrs: nounwind
19define i32 @fn1() {
20; CHECK-LABEL: @fn1(
21; CHECK-NEXT:  entry:
22; CHECK-NEXT:    [[TMP0:%.*]] = load i32, ptr @b, align 4
23; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i32 [[TMP0]], 0
24; CHECK-NEXT:    br i1 [[TOBOOL]], label [[RETURN:%.*]], label [[IF_THEN:%.*]]
25; CHECK:       if.then:
26; CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr @a, align 4
27; CHECK-NEXT:    [[SWITCH_SELECTCMP:%.*]] = icmp eq i32 [[TMP1]], 0
28; CHECK-NEXT:    [[SWITCH_SELECT:%.*]] = select i1 [[SWITCH_SELECTCMP]], i32 0, i32 0
29; CHECK-NEXT:    [[SWITCH_SELECTCMP1:%.*]] = icmp eq i32 [[TMP1]], 5
30; CHECK-NEXT:    [[SWITCH_SELECT2:%.*]] = select i1 [[SWITCH_SELECTCMP1]], i32 5, i32 [[SWITCH_SELECT]]
31; CHECK-NEXT:    br label [[RETURN]]
32; CHECK:       return:
33; CHECK-NEXT:    [[RETVAL_0:%.*]] = phi i32 [ [[SWITCH_SELECT2]], [[IF_THEN]] ], [ 0, [[ENTRY:%.*]] ]
34; CHECK-NEXT:    ret i32 [[RETVAL_0]]
35;
36entry:
37  %0 = load i32, ptr @b, align 4
38  %tobool = icmp eq i32 %0, 0
39  br i1 %tobool, label %if.end3, label %if.then
40
41if.then:
42  %1 = load i32, ptr @a, align 4
43  switch i32 %1, label %if.end3 [
44  i32 5, label %return
45  i32 0, label %return
46  ]
47
48if.end3:
49  br label %return
50
51return:
52  %retval.0 = phi i32 [ 0, %if.end3 ], [ %1, %if.then ], [ %1, %if.then ]
53  ret i32 %retval.0
54}
55
56