[llvm] [WIP][CodeGen] Modifying MBB's liveins representation as into regUnits (PR #129847)

[Vikash Gupta via llvm-commits]

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@@ -174,8 +176,7 @@ class MachineBasicBlock
   std::optional<uint64_t> IrrLoopHeaderWeight;
 
   /// Keep track of the physical registers that are livein of the basicblock.
-  using LiveInVector = std::vector<RegisterMaskPair>;
-  LiveInVector LiveIns;
+  DenseSet<MCRegister> LiveIns;
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vg0204 wrote:

@nikic can you add my forked repo https://github.com/vg0204/llvm-project.git for benchmarking it!

https://github.com/llvm/llvm-project/pull/129847