[llvm] [llvm][ctx_profile] Add instrumentation lowering (PR #90821)

[Snehasish Kumar via llvm-commits]

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@@ -14156,10 +14175,10 @@ Syntax:
 Overview:
 """""""""
 
-.. FIXME: detail when it's emitted once the support is added
-
 The '``llvm.instrprof.callsite``' intrinsic should be emitted before a callsite
-that's not to a "fake" callee (like another intrinsic or asm).
+that's not to a "fake" callee (like another intrinsic or asm). It is used by
+contextual profiling and is side-effectful. Its lowering happens in IR, and
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snehasish wrote:

"has side-effects"?

https://github.com/llvm/llvm-project/pull/90821