xref: /llvm-project/llvm/test/Transforms/GlobalDCE/virtual-functions-derived-call.ll (revision 0f46e31cfbf415fcd3d3ce121bef94e92c6ccfc8) 
1; RUN: opt < %s -passes=globaldce -S | FileCheck %s
2
3target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
4
5; struct A {
6;   A();
7;   virtual int foo();
8; };
9;
10; struct B : A {
11;   B();
12;   virtual int foo();
13; };
14;
15; A::A() {}
16; B::B() {}
17; int A::foo() { return 42; }
18; int B::foo() { return 1337; }
19;
20; extern "C" int test(B *p) { return p->foo(); }
21
22; The virtual call in test can only be dispatched to B::foo (or a more-derived
23; class, if there was one), so A::foo can be removed.
24
25%struct.A = type { ptr }
26%struct.B = type { %struct.A }
27
28; CHECK: @_ZTV1A = internal unnamed_addr constant { [3 x ptr] } zeroinitializer
29@_ZTV1A = internal unnamed_addr constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr null, ptr @_ZN1A3fooEv] }, align 8, !type !0, !type !1, !vcall_visibility !2
30
31; CHECK: @_ZTV1B = internal unnamed_addr constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr null, ptr @_ZN1B3fooEv] }
32@_ZTV1B = internal unnamed_addr constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr null, ptr @_ZN1B3fooEv] }, align 8, !type !0, !type !1, !type !3, !type !4, !vcall_visibility !2
33
34; CHECK-NOT: define internal i32 @_ZN1A3fooEv(
35define internal i32 @_ZN1A3fooEv(ptr nocapture readnone %this) {
36entry:
37  ret i32 42
38}
39
40; CHECK: define internal i32 @_ZN1B3fooEv(
41define internal i32 @_ZN1B3fooEv(ptr nocapture readnone %this) {
42entry:
43  ret i32 1337
44}
45
46define hidden void @_ZN1AC2Ev(ptr nocapture %this) {
47entry:
48  store ptr getelementptr inbounds inrange(-16, 8) ({ [3 x ptr] }, ptr @_ZTV1A, i64 0, i32 0, i64 2), ptr %this, align 8
49  ret void
50}
51
52define hidden void @_ZN1BC2Ev(ptr nocapture %this) {
53entry:
54  store ptr getelementptr inbounds inrange(-16, 8) ({ [3 x ptr] }, ptr @_ZTV1B, i64 0, i32 0, i64 2), ptr %this, align 8
55  ret void
56}
57
58define hidden i32 @test(ptr %p) {
59entry:
60  %vtable1 = load ptr, ptr %p, align 8
61  %0 = tail call { ptr, i1 } @llvm.type.checked.load(ptr %vtable1, i32 0, metadata !"_ZTS1B"), !nosanitize !10
62  %1 = extractvalue { ptr, i1 } %0, 0, !nosanitize !10
63  %call = tail call i32 %1(ptr %p)
64  ret i32 %call
65}
66
67declare { ptr, i1 } @llvm.type.checked.load(ptr, i32, metadata) #2
68
69!llvm.module.flags = !{!5}
70
71!0 = !{i64 16, !"_ZTS1A"}
72!1 = !{i64 16, !"_ZTSM1AFivE.virtual"}
73!2 = !{i64 2}
74!3 = !{i64 16, !"_ZTS1B"}
75!4 = !{i64 16, !"_ZTSM1BFivE.virtual"}
76!5 = !{i32 1, !"Virtual Function Elim", i32 1}
77!10 = !{}
78