[llvm] [profcheck] Require `unknown` metadata have an origin parameter (PR #157594)

[David Li via llvm-commits]

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@@ -140,12 +142,38 @@ define void @test() !prof !0 {
 }
 
 !0 = !{!"unknown", i64 123}
-; ON-FUNCTION2: first operand should be 'function_entry_count' or 'synthetic_function_entry_count'
+; ON-FUNCTION2: 'unknown' !prof should have an additional operand of type string
 
 ;--- invalid-unknown-placement.ll
 define i32 @test() {
   %r = add i32 1, 2, !prof !0
   ret i32 %r
 }
-!0 = !{!"unknown"}
+!0 = !{!"unknown", !"test"}
 ; INVALID-UNKNOWN-PLACEMENT: 'unknown' !prof should only appear on instructions on which 'branch_weights' would
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david-xl wrote:

does it break IR compatibility? 

https://github.com/llvm/llvm-project/pull/157594