[all-commits] [llvm/llvm-project] ee1c85: [DebugInfo][InstrRef] Treat ORRWrr as a copy instr...

[Shubham Sandeep Rastogi via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ee1c85225235c4353555a17b73ba16a2f177265b
      https://github.com/llvm/llvm-project/commit/ee1c85225235c4353555a17b73ba16a2f177265b
  Author: Shubham Sandeep Rastogi <srastogi22 at apple.com>
  Date:   2025-01-17 (Fri, 17 Jan 2025)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
    A llvm/test/CodeGen/AArch64/instr-ref-ldv.ll

  Log Message:
  -----------
  [DebugInfo][InstrRef] Treat ORRWrr as a copy instr (#123102)

The insturction selector uses the `MachineFunction::copySalvageSSA`
function to insert `DBG_PHIs` or identify a defining instruction for a
copy-like instruction when finalizing Instruction References.

AArch64 has the ORR instruction which is a logical OR with the variants
ORRWrr which refers to a register to register variant, and ORRWrs which
is a register to a shifted register variant.

An ORRWrs where the shift amount is 0, and the zero register ($wzr) is
used is considered a copy, for example:

`$w0 = ORRWrs $wzr, killed $w3, 0`

However an ORRWrr with a zero register is not considered a copy

`$w0 = ORRWrr $wzr, killed $w3`

This causes an issue in the livedebugvalues pass because in aarch64-isel
the instruction is the ORRWrr variant, but is then changed to the ORRWrs
variant before the livedebugvalues pass.

This causes a mismatch between the two passes which leads to a crash in
the livedebugvalues pass.

This patch fixes the issue.



To unsubscribe from these emails, change your notification settings at https://github.com/llvm/llvm-project/settings/notifications