[llvm] [AMDGPU] Introduce Next-Use Analysis for SSA-based Register Allocation (PR #156079)

[via llvm-commits]

================
@@ -0,0 +1,482 @@
+//===-- AMDGPUNextUseAnalysis.cpp - Next Use Analysis ---------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file
+/// This file implements the Next Use Analysis for AMDGPU targets.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AMDGPUNextUseAnalysis.h"
+#include "AMDGPU.h"
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionAnalysis.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/SlotIndexes.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/MC/LaneBitmask.h"
+#include "llvm/Passes/PassBuilder.h"
+#include "llvm/Passes/PassPlugin.h"
+#include "llvm/Support/Timer.h"
+
+#define DEBUG_TYPE "amdgpu-next-use"
+
+using namespace llvm;
+
----------------
ruiling wrote:

I think we need some implementation notes here to explain how the analysis works overall and the key details.

https://github.com/llvm/llvm-project/pull/156079