xref: /llvm-project/llvm/test/Analysis/MemorySSA/load-invariant.ll (revision 8e44f13c6d294e6b4864441b22045b507782540c)
1; RUN: opt -aa-pipeline=basic-aa -passes='print<memoryssa>' -verify-memoryssa -disable-output < %s 2>&1 | FileCheck %s
2;
3; Invariant loads should be considered live on entry, because, once the
4; location is known to be dereferenceable, the value can never change.
5
6@g = external global i32
7
8declare void @clobberAllTheThings()
9
10; CHECK-LABEL: define i32 @foo
11define i32 @foo() {
12; CHECK: 1 = MemoryDef(liveOnEntry)
13; CHECK-NEXT: call void @clobberAllTheThings()
14  call void @clobberAllTheThings()
15; CHECK: MemoryUse(liveOnEntry)
16; CHECK-NEXT: %1 = load i32
17  %1 = load i32, ptr @g, align 4, !invariant.load !0
18  ret i32 %1
19}
20
21; CHECK-LABEL: define i32 @bar
22define i32 @bar(ptr %a) {
23; CHECK: 1 = MemoryDef(liveOnEntry)
24; CHECK-NEXT: call void @clobberAllTheThings()
25  call void @clobberAllTheThings()
26
27; CHECK: 2 = MemoryDef(1)
28; CHECK-NEXT: %1 = load atomic i32
29  %1 = load atomic i32, ptr %a acquire, align 4, !invariant.load !0
30
31; CHECK: MemoryUse(2)
32; CHECK-NEXT: %2 = load i32
33  %2 = load i32, ptr %a, align 4
34  ret i32 %2
35}
36
37!0 = !{}
38