xref: /llvm-project/llvm/test/Transforms/SimplifyCFG/UncondBranchToReturn.ll (revision d1d129356909af2f6fefd6f1b9335a39fe172e9a)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; The unify-function-exit-nodes pass often makes basic blocks that just contain
3; a PHI node and a return.  Make sure the simplify cfg can straighten out this
4; important case.  This is basically the most trivial form of tail-duplication.
5
6; RUN: opt < %s -passes=simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=true -S | FileCheck %s
7
8define i32 @test(i1 %B, i32 %A, i32 %B.upgrd.1) {
9; CHECK-LABEL: @test(
10; CHECK-NEXT:  ret:
11; CHECK-NEXT:    [[B_UPGRD_1_A:%.*]] = select i1 [[B:%.*]], i32 [[B_UPGRD_1:%.*]], i32 [[A:%.*]]
12; CHECK-NEXT:    ret i32 [[B_UPGRD_1_A]]
13;
14  br i1 %B, label %T, label %F
15T:              ; preds = %0
16  br label %ret
17F:              ; preds = %0
18  br label %ret
19ret:            ; preds = %F, %T
20  %X = phi i32 [ %A, %F ], [ %B.upgrd.1, %T ]             ; <i32> [#uses=1]
21  ret i32 %X
22}
23
24
25; Make sure it's willing to move unconditional branches to return instructions
26; as well, even if the return block is shared and the source blocks are
27; non-empty.
28define i32 @test2(i1 %B, i32 %A, i32 %B.upgrd.2) {
29; CHECK-LABEL: @test2(
30; CHECK-NEXT:  ret:
31; CHECK-NEXT:    [[TMP0:%.*]] = call i32 @test(i1 true, i32 5, i32 8)
32; CHECK-NEXT:    ret i32 [[A:%.*]]
33;
34  br i1 %B, label %T, label %F
35T:              ; preds = %0
36  call i32 @test( i1 true, i32 5, i32 8 )         ; <i32>:1 [#uses=0]
37  br label %ret
38F:              ; preds = %0
39  call i32 @test( i1 true, i32 5, i32 8 )         ; <i32>:2 [#uses=0]
40  br label %ret
41ret:            ; preds = %F, %T
42  ret i32 %A
43}
44