[all-commits] [llvm/llvm-project] 59bf60: Refactor recomputeLiveIns to operate on whole CFG ...

[Oskar Wirga via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 59bf60519fc30d9d36c86abd83093b068f6b1e4b
      https://github.com/llvm/llvm-project/commit/59bf60519fc30d9d36c86abd83093b068f6b1e4b
  Author: Oskar Wirga <10386631+oskarwirga at users.noreply.github.com>
  Date:   2024-01-26 (Fri, 26 Jan 2024)

  Changed paths:
    M llvm/include/llvm/CodeGen/LivePhysRegs.h
    M llvm/include/llvm/CodeGen/MachineBasicBlock.h
    M llvm/lib/CodeGen/BranchFolding.cpp
    M llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
    M llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
    M llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
    M llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp
    M llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
    M llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
    M llvm/lib/Target/X86/X86FrameLowering.cpp
    M llvm/test/CodeGen/AArch64/stack-probing-last-in-block.mir
    M llvm/test/CodeGen/SystemZ/branch-folder-hoist-livein.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/biquad-cascade-default.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/biquad-cascade-optsize-strd-lr.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/biquad-cascade-optsize.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/it-block-mov.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/loop-dec-copy-chain.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/loop-dec-copy-prev-iteration.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/loop-dec-liveout.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/matrix-debug.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/matrix.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/mov-after-dlstp.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/multi-block-cond-iter-count.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/multiple-do-loops.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/predicated-liveout.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/remove-elem-moves.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/skip-debug.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/skip-vpt-debug.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/spillingmove.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/unrolled-and-vector.mir

  Log Message:
  -----------
  Refactor recomputeLiveIns to operate on whole CFG (#79498)

Currently, the way that recomputeLiveIns works is that it will recompute
the livein registers for that MachineBasicBlock but it matters what
order you call recomputeLiveIn which can result in incorrect register
allocations down the line.

This PR fixes that by simply recomputing the liveins for the entire CFG
until convergence is achieved. This makes it harder to introduce subtle
bugs which alter liveness.