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; RUN: llvm-as <%s -bitcode-mdindex-threshold=0 | llvm-bcanalyzer -dump | FileCheck %s
; Check that distinct nodes break uniquing cycles, so that uniqued subgraphs
; are always in post-order.
;
; It may not be immediately obvious why this is an interesting graph. There
; are three nodes in a cycle, and one of them (!1) is distinct. Because the
; entry point is !2, a naive post-order traversal would give !3, !1, !2; but
; this means when !3 is parsed the reader will need a forward reference for !2.
; Forward references for uniqued node operands are expensive, whereas they're
; cheap for distinct node operands. If the distinct node is emitted first, the
; uniqued nodes don't need any forward references at all.
; Nodes in this testcase are numbered to match how they are referenced in
; bitcode. !3 is referenced as opN=3.
; CHECK: <DISTINCT_NODE op0=3/>
!1 = distinct !{!3}
; CHECK-NEXT: <NODE op0=1/>
!2 = !{!1}
; CHECK-NEXT: <NODE op0=2/>
!3 = !{!2}
; Before the named records we emit the index containing the position of the
; previously emitted records
; CHECK-NEXT: <INDEX {{.*}} (offset match)
; Note: named metadata nodes are not cannot reference null so their operands
; are numbered off-by-one.
; CHECK-NEXT: <NAME
; CHECK-NEXT: <NAMED_NODE op0=1/>
!named = !{!2}
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