1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
; RUN: opt < %s -passes=deadargelim -S | FileCheck %s
%Ty = type { i32, i32 }
; Validate that the argument and return value are both dead
; CHECK-LABEL: define internal void @test1()
define internal %Ty* @test1(%Ty* %this) {
ret %Ty* %this
}
; do not keep alive the return value of a function with a dead 'returned' argument
; CHECK-LABEL: define internal void @test2()
define internal %Ty* @test2(%Ty* returned %this) {
ret %Ty* %this
}
; dummy to keep 'this' alive
@dummy = global %Ty* null
; Validate that return value is dead
; CHECK-LABEL: define internal void @test3(%Ty* %this)
define internal %Ty* @test3(%Ty* %this) {
store volatile %Ty* %this, %Ty** @dummy
ret %Ty* %this
}
; keep alive return value of a function if the 'returned' argument is live
; CHECK-LABEL: define internal %Ty* @test4(%Ty* returned %this)
define internal %Ty* @test4(%Ty* returned %this) {
store volatile %Ty* %this, %Ty** @dummy
ret %Ty* %this
}
; don't do this if 'returned' is on the call site...
; CHECK-LABEL: define internal void @test5(%Ty* %this)
define internal %Ty* @test5(%Ty* %this) {
store volatile %Ty* %this, %Ty** @dummy
ret %Ty* %this
}
; Drop all these attributes
; CHECK-LABEL: define internal void @test6
define internal align 8 dereferenceable_or_null(2) noundef noalias i8* @test6() {
ret i8* null
}
define %Ty* @caller(%Ty* %this) {
%1 = call %Ty* @test1(%Ty* %this)
%2 = call %Ty* @test2(%Ty* %this)
%3 = call %Ty* @test3(%Ty* %this)
%4 = call %Ty* @test4(%Ty* %this)
; ...instead, drop 'returned' form the call site
; CHECK: call void @test5(%Ty* %this)
%5 = call %Ty* @test5(%Ty* returned %this)
%6 = call i8* @test6()
ret %Ty* %this
}
|
