[llvm] Adding Matching and Inference Functionality to Propeller-PR4: Implement matching and inference and create clusters (PR #165868)

[via llvm-commits]

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@@ -0,0 +1,187 @@
+//===- llvm/CodeGen/BasicBlockMatchingAndInference.cpp ----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Infer weights for all basic blocks using matching and inference.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/BasicBlockMatchingAndInference.h"
+#include "llvm/CodeGen/BasicBlockSectionsProfileReader.h"
+#include "llvm/CodeGen/MachineBlockHashInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/InitializePasses.h"
+#include <llvm/Support/CommandLine.h>
+
+using namespace llvm;
+
+static cl::opt<float>
+    PropellerInferThreshold("propeller-infer-threshold",
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spupyrev wrote:

Why is this in `llvm/lib/CodeGen`? Is this implementation tied to the Propeller use case, or a general one?
I'm confused because we have a very similar code for BOLT in `bolt/lib/Profile/StaleProfileMatching.cpp`.

https://github.com/llvm/llvm-project/pull/165868