[llvm] [llvm][ctx_profile] Add instrumentation (PR #90136)

[Ellis Hoag via llvm-commits]

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@@ -0,0 +1,41 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals all --version 4
+; RUN: opt -passes=pgo-instr-gen -profile-context-root=an_entrypoint \
+; RUN:   -S < %s | FileCheck --check-prefix=INSTRUMENT %s
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ellishg wrote:

```suggestion
; RUN: opt -passes=pgo-instr-gen -profile-context-root=an_entrypoint \
; RUN:   -S < %s | FileCheck %s
```

NIT: Why not use the default check prefix `CHECK`?

https://github.com/llvm/llvm-project/pull/90136