xref: /llvm-project/llvm/test/Transforms/CodeGenPrepare/X86/fake-use-split-ret.ll (revision 822f74a91106b7ca10e85508eb642e62ef945afa)
1; RUN: opt -mtriple=x86_64-unknown-unknown -S -codegenprepare <%s -o - | FileCheck %s
2;
3; Ensure return instruction splitting ignores fake uses.
4;
5; IR Generated with clang -O2 -S -emit-llvm -fextend-variable-liveness test.cpp
6;
7;// test.cpp
8;extern int bar(int);
9;
10;int foo2(int i)
11;{
12;  --i;
13;  if (i <= 0)
14;    return -1;
15;  return bar(i);
16;}
17
18declare i32 @_Z3bari(i32) local_unnamed_addr
19
20define i32 @_Z4foo2i(i32 %i) local_unnamed_addr optdebug {
21entry:
22  %dec = add nsw i32 %i, -1
23  %cmp = icmp slt i32 %i, 2
24  br i1 %cmp, label %cleanup, label %if.end
25
26if.end:                                           ; preds = %entry
27  %call = tail call i32 @_Z3bari(i32 %dec)
28; CHECK: ret i32 %call
29  br label %cleanup
30
31cleanup:                                          ; preds = %entry, %if.end
32; CHECK: cleanup:
33  %retval.0 = phi i32 [ %call, %if.end ], [ -1, %entry ]
34  tail call void (...) @llvm.fake.use(i32 %dec)
35; CHECK: ret i32 -1
36  ret i32 %retval.0
37}
38