xref: /llvm-project/llvm/test/Transforms/MemCpyOpt/stackrestore.ll (revision 25bc999d1fb2efccc3ece398550af738aea7d310)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; RUN: opt -S -passes=memcpyopt < %s -verify-memoryssa | FileCheck %s
3
4; PR40118: BasicAA didn't realize that stackrestore ends the lifetime of
5; unescaped dynamic allocas, such as those that might come from inalloca.
6
7source_filename = "t.cpp"
8target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
9target triple = "i686-unknown-windows-msvc19.14.26433"
10
11@str = internal constant [9 x i8] c"abcdxxxxx"
12
13
14; Test that we can propagate memcpy through an unescaped dynamic alloca across
15; a call to @external.
16
17define i32 @test_norestore(i32 %n) {
18; CHECK-LABEL: @test_norestore(
19; CHECK-NEXT:    [[TMPMEM:%.*]] = alloca [10 x i8], align 4
20; CHECK-NEXT:    [[P:%.*]] = alloca i8, i32 [[N:%.*]], align 4
21; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr [[P]], ptr align 1 @str, i32 9, i1 false)
22; CHECK-NEXT:    [[P10:%.*]] = getelementptr inbounds i8, ptr [[P]], i32 9
23; CHECK-NEXT:    store i8 0, ptr [[P10]], align 1
24; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr [[TMPMEM]], ptr [[P]], i32 10, i1 false)
25; CHECK-NEXT:    call void @external()
26; CHECK-NEXT:    [[HEAP:%.*]] = call ptr @malloc(i32 9)
27; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr [[HEAP]], ptr align 1 @str, i32 9, i1 false)
28; CHECK-NEXT:    call void @useit(ptr [[HEAP]])
29; CHECK-NEXT:    ret i32 0
30;
31  %tmpmem = alloca [10 x i8], align 4
32
33  ; Make a dynamic alloca, initialize it.
34  %p = alloca i8, i32 %n, align 4
35  call void @llvm.memcpy.p0.p0.i32(ptr %p, ptr align 1 @str, i32 9, i1 false)
36
37  ; This extra byte exists to prevent memcpyopt from propagating @str.
38  %p10 = getelementptr inbounds i8, ptr %p, i32 9
39  store i8 0, ptr %p10
40
41  call void @llvm.memcpy.p0.p0.i32(ptr %tmpmem, ptr %p, i32 10, i1 false)
42  call void @external()
43  %heap = call ptr @malloc(i32 9)
44  call void @llvm.memcpy.p0.p0.i32(ptr %heap, ptr %tmpmem, i32 9, i1 false)
45  call void @useit(ptr %heap)
46  ret i32 0
47}
48
49; Do not propagate memcpy from %p across the stackrestore.
50
51define i32 @test_stackrestore() {
52; CHECK-LABEL: @test_stackrestore(
53; CHECK-NEXT:    [[TMPMEM:%.*]] = alloca [10 x i8], align 4
54; CHECK-NEXT:    [[INALLOCA_SAVE:%.*]] = tail call ptr @llvm.stacksave.p0()
55; CHECK-NEXT:    [[ARGMEM:%.*]] = alloca inalloca [10 x i8], align 4
56; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr [[ARGMEM]], ptr align 1 @str, i32 9, i1 false)
57; CHECK-NEXT:    [[P10:%.*]] = getelementptr inbounds [10 x i8], ptr [[ARGMEM]], i32 0, i32 9
58; CHECK-NEXT:    store i8 0, ptr [[P10]], align 1
59; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr [[TMPMEM]], ptr [[ARGMEM]], i32 10, i1 false)
60; CHECK-NEXT:    call void @llvm.stackrestore.p0(ptr [[INALLOCA_SAVE]])
61; CHECK-NEXT:    [[HEAP:%.*]] = call ptr @malloc(i32 9)
62; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i32(ptr [[HEAP]], ptr [[TMPMEM]], i32 9, i1 false)
63; CHECK-NEXT:    call void @useit(ptr [[HEAP]])
64; CHECK-NEXT:    ret i32 0
65;
66  %tmpmem = alloca [10 x i8], align 4
67  %inalloca.save = tail call ptr @llvm.stacksave()
68  %argmem = alloca inalloca [10 x i8], align 4
69  call void @llvm.memcpy.p0.p0.i32(ptr %argmem, ptr align 1 @str, i32 9, i1 false)
70
71  ; This extra byte exists to prevent memcpyopt from propagating @str.
72  %p10 = getelementptr inbounds [10 x i8], ptr %argmem, i32 0, i32 9
73  store i8 0, ptr %p10
74
75  call void @llvm.memcpy.p0.p0.i32(ptr %tmpmem, ptr %argmem, i32 10, i1 false)
76  call void @llvm.stackrestore(ptr %inalloca.save)
77  %heap = call ptr @malloc(i32 9)
78  call void @llvm.memcpy.p0.p0.i32(ptr %heap, ptr %tmpmem, i32 9, i1 false)
79  call void @useit(ptr %heap)
80  ret i32 0
81}
82
83declare void @llvm.memcpy.p0.p0.i32(ptr nocapture writeonly, ptr nocapture readonly, i32, i1)
84declare ptr @llvm.stacksave()
85declare void @llvm.stackrestore(ptr)
86declare ptr @malloc(i32)
87declare void @useit(ptr)
88declare void @external()
89