xref: /llvm-project/llvm/test/Analysis/GlobalsModRef/memset-escape.ll (revision 47f0b6630c78ab52c2197ec5e1c2d13a6acffed1)
1; RUN: opt < %s -O1 -S | FileCheck %s
2
3target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
4target triple = "x86_64-apple-macosx10.10.0"
5
6@a = internal global [3 x i32] zeroinitializer, align 4
7@b = common global i32 0, align 4
8
9; The important thing we're checking for here is the reload of (some element of)
10; @a after the memset.
11
12; CHECK-LABEL: @main
13; CHECK: call void @llvm.memset.p0.i64{{.*}} @a
14; CHECK: store i32 3
15; CHECK: load i32, ptr getelementptr {{.*}} @a
16; CHECK: icmp eq i32
17; CHECK: br i1
18
19define i32 @main() {
20entry:
21  %retval = alloca i32, align 4
22  %c = alloca [1 x i32], align 4
23  store i32 0, ptr %retval, align 4
24  call void @llvm.memset.p0.i64(ptr align 4 %c, i8 0, i64 4, i1 false)
25  store i32 1, ptr getelementptr inbounds ([3 x i32], ptr @a, i64 0, i64 2), align 4
26  store i32 0, ptr @b, align 4
27  br label %for.cond
28
29for.cond:                                         ; preds = %for.inc, %entry
30  %0 = load i32, ptr @b, align 4
31  %cmp = icmp slt i32 %0, 3
32  br i1 %cmp, label %for.body, label %for.end
33
34for.body:                                         ; preds = %for.cond
35  %1 = load i32, ptr @b, align 4
36  %idxprom = sext i32 %1 to i64
37  %arrayidx = getelementptr inbounds [3 x i32], ptr @a, i64 0, i64 %idxprom
38  store i32 0, ptr %arrayidx, align 4
39  br label %for.inc
40
41for.inc:                                          ; preds = %for.body
42  %2 = load i32, ptr @b, align 4
43  %inc = add nsw i32 %2, 1
44  store i32 %inc, ptr @b, align 4
45  br label %for.cond
46
47for.end:                                          ; preds = %for.cond
48  %3 = load i32, ptr getelementptr inbounds ([3 x i32], ptr @a, i64 0, i64 2), align 4
49  %cmp1 = icmp ne i32 %3, 0
50  br i1 %cmp1, label %if.then, label %if.end
51
52if.then:                                          ; preds = %for.end
53  call void @abort() #3
54  unreachable
55
56if.end:                                           ; preds = %for.end
57  ret i32 0
58}
59
60; Function Attrs: nounwind argmemonly
61declare void @llvm.memset.p0.i64(ptr nocapture, i8, i64, i1) nounwind argmemonly
62
63; Function Attrs: noreturn nounwind
64declare void @abort() noreturn nounwind
65