[llvm] [MCA] Enable customization of individual instructions (PR #155420)

[Roman Belenov via llvm-commits]

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@@ -42,19 +43,91 @@ CustomBehaviour::getEndViews(llvm::MCInstPrinter &IP,
   return std::vector<std::unique_ptr<View>>();
 }
 
+class CustomInstrument : public Instrument {
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r-belenov wrote:

I've added target IM creation into default IM constructor to simplify the logic in the tool code.

https://github.com/llvm/llvm-project/pull/155420