1; Test that the strncpy library call simplifier works correctly.
2;
3; RUN: opt < %s -instcombine -S | FileCheck %s
4
5target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
6
7@hello = constant [6 x i8] c"hello\00"
8@null = constant [1 x i8] zeroinitializer
9@null_hello = constant [7 x i8] c"\00hello\00"
10@a = common global [32 x i8] zeroinitializer, align 1
11@b = common global [32 x i8] zeroinitializer, align 1
12
13declare i8* @strncpy(i8*, i8*, i32)
14declare i32 @puts(i8*)
15
16; Check a bunch of strncpy invocations together.
17
18define i32 @test_simplify1() {
19; CHECK-LABEL: @test_simplify1(
20; CHECK-NOT: call i8* @strncpy
21; CHECK: call i32 @puts
22  %target = alloca [1024 x i8]
23  %arg1 = getelementptr [1024 x i8], [1024 x i8]* %target, i32 0, i32 0
24  store i8 0, i8* %arg1
25
26  %arg2 = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
27  %rslt1 = call i8* @strncpy(i8* %arg1, i8* %arg2, i32 6)
28
29  %arg3 = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
30  %rslt2 = call i8* @strncpy(i8* %rslt1, i8* %arg3, i32 42)
31
32  %arg4 = getelementptr [7 x i8], [7 x i8]* @null_hello, i32 0, i32 0
33  %rslt3 = call i8* @strncpy(i8* %rslt2, i8* %arg4, i32 42)
34
35  call i32 @puts( i8* %rslt3 )
36  ret i32 0
37}
38
39; Check strncpy(x, "", y) -> memset(x, '\0', y, 1).
40
41define void @test_simplify2() {
42; CHECK-LABEL: @test_simplify2(
43  %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
44  %src = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
45
46  call i8* @strncpy(i8* %dst, i8* %src, i32 32)
47; CHECK: call void @llvm.memset.p0i8.i32
48  ret void
49}
50
51; Check strncpy(x, y, 0) -> x.
52
53define i8* @test_simplify3() {
54; CHECK-LABEL: @test_simplify3(
55  %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
56  %src = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
57
58  %ret = call i8* @strncpy(i8* %dst, i8* %src, i32 0)
59  ret i8* %ret
60; CHECK: ret i8* getelementptr inbounds ([32 x i8], [32 x i8]* @a, i32 0, i32 0)
61}
62
63; Check  strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant].
64
65define void @test_simplify4() {
66; CHECK-LABEL: @test_simplify4(
67  %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
68  %src = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
69
70  call i8* @strncpy(i8* %dst, i8* %src, i32 6)
71; CHECK: call void @llvm.memcpy.p0i8.p0i8.i32
72  ret void
73}
74
75; Check cases that shouldn't be simplified.
76
77define void @test_no_simplify1() {
78; CHECK-LABEL: @test_no_simplify1(
79  %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
80  %src = getelementptr [32 x i8], [32 x i8]* @b, i32 0, i32 0
81
82  call i8* @strncpy(i8* %dst, i8* %src, i32 32)
83; CHECK: call i8* @strncpy
84  ret void
85}
86
87define void @test_no_simplify2() {
88; CHECK-LABEL: @test_no_simplify2(
89  %dst = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
90  %src = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
91
92  call i8* @strncpy(i8* %dst, i8* %src, i32 8)
93; CHECK: call i8* @strncpy
94  ret void
95}
96