[PATCH] D153093: [MBP] Enable duplicating return block to remove jump to return

[Guozhi Wei via Phabricator via llvm-commits]

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Sometimes LLVM generates branch to return instruction, like PR63227.

It is because in function MachineBlockPlacement::canTailDuplicateUnplacedPreds we avoid duplicating a BB into another already placed BB to prevent destroying computed layout. But if the successor BB is a return block, duplicating it will only reduce taken branches without hurt to any other branches.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D153093

Files:
  llvm/lib/CodeGen/MachineBlockPlacement.cpp
  llvm/test/CodeGen/AArch64/aarch64-matrix-umull-smull.ll
  llvm/test/CodeGen/Thumb/branch-to-return.ll
  llvm/test/CodeGen/Thumb2/LowOverheadLoops/mve-float-loops.ll
  llvm/test/CodeGen/Thumb2/mve-vecreduce-loops.ll

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