[llvm] [RISCV64] liveness analysis (PR #167454)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,598 @@
+//===- RISCVLiveVariables.cpp - Live Variable Analysis for RISC-V --------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a live variable analysis pass for the RISC-V backend.
+// The pass computes liveness information for virtual and physical registers
+// in RISC-V machine functions, optimized for RV64 (64-bit RISC-V architecture).
+//
+// The analysis performs a backward dataflow analysis to compute
+// liveness information. Also updates the kill flags on register operands.
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arsenm wrote:

Kill flags are deprecated, should not be introducing new code computing or depending on them. We should be deleting the current LiveVariables pass 

https://github.com/llvm/llvm-project/pull/167454