[all-commits] [llvm/llvm-project] 31f81e: [RA] Don't split a register generated from another...

[weiguozhi via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 31f81e96a4dac353d7a6c9cb4b4553c60fb732bd
      https://github.com/llvm/llvm-project/commit/31f81e96a4dac353d7a6c9cb4b4553c60fb732bd
  Author: weiguozhi <57237827+weiguozhi at users.noreply.github.com>
  Date:   2023-09-26 (Tue, 26 Sep 2023)

  Changed paths:
    M llvm/lib/CodeGen/RegAllocGreedy.cpp
    A llvm/test/CodeGen/ARM/split-deadloop.mir

  Log Message:
  -----------
  [RA] Don't split a register generated from another split (#67351)

Split a register generated from another split usually doesn't bring us
too much benefit. It may also cause dead loop as pr67188 shows if the
heuristic cost always satisfy the split condition. So prevent such
splitting.

It fixed pr67188.