xref: /llvm-project/llvm/test/Transforms/InstCombine/prefetch-load.ll (revision 4ab40eca080965c65802710e39adbb78c4ce7bde)
1; RUN: opt < %s -passes=instcombine -S | FileCheck %s
2
3%struct.C = type { ptr, i32 }
4
5; Check that we instcombine the load across the prefetch.
6
7; CHECK-LABEL: define signext i32 @foo
8define signext i32 @foo(ptr %c) local_unnamed_addr #0 {
9; CHECK: store i32 %dec, ptr %length_
10; CHECK-NOT: load
11; CHECK: llvm.prefetch
12; CHECK-NEXT: ret
13entry:
14  %0 = load ptr, ptr %c, align 8
15  %1 = load ptr, ptr %0, align 8
16  store ptr %1, ptr %c, align 8
17  %length_ = getelementptr inbounds %struct.C, ptr %c, i32 0, i32 1
18  %2 = load i32, ptr %length_, align 8
19  %dec = add nsw i32 %2, -1
20  store i32 %dec, ptr %length_, align 8
21  call void @llvm.prefetch(ptr %1, i32 0, i32 0, i32 1)
22  %3 = load i32, ptr %length_, align 8
23  ret i32 %3
24}
25
26; Function Attrs: inaccessiblemem_or_argmemonly nounwind
27declare void @llvm.prefetch(ptr nocapture readonly, i32, i32, i32)
28
29attributes #0 = { noinline nounwind }
30; We've explicitly removed the function attrs from llvm.prefetch so we get the defaults.
31; attributes #1 = { inaccessiblemem_or_argmemonly nounwind }
32