[llvm] [InstrRef] Fix mismatch between LiveDebugValues and salvageCopySSA (PR #124233)

[Shubham Sandeep Rastogi via llvm-commits]

https://github.com/rastogishubham created https://github.com/llvm/llvm-project/pull/124233

The LiveDebugValues pass and the instruction selector (which calls) salvageCopySSA need to be consistent on what they consider a copy instruction. With https://github.com/llvm/llvm-project/pull/75184, the definition of what a copy instruction is was narrowed for AArch64 to exclude a w->x ORR and treat it as a zero-extend rather than a copy

However, to make sure LiveDebugValues still treats a w->x ORR as a copy, the new function, isCopyLikeInstr was created. We need to make sure that salvageCopySSA also calls that function.

This patch addresses this mismatch.

>From ce6f57c659b159aaef2c84d8cf5a1d7106019293 Mon Sep 17 00:00:00 2001
From: Shubham Sandeep Rastogi <srastogi22 at apple.com>
Date: Thu, 23 Jan 2025 22:07:27 -0800
Subject: [PATCH] [InstrRef] Fix mismatch between LiveDebugValues and
 salvageCopySSA

The LiveDebugValues pass and the instruction selector (which calls)
salvageCopySSA need to be consistent on what they consider a copy
instruction. With https://github.com/llvm/llvm-project/pull/75184, the
definition of what a copy instruction is was narrowed for AArch64 to
exclude a w->x ORR and treat it as a zero-extend rather than a copy

However, to make sure LiveDebugValues still treats a w->x ORR as a copy,
the new function, isCopyLikeInstr was created. We need to make sure that
salvageCopySSA also calls that function.

This patch addresses this mismatch.
---
 llvm/lib/CodeGen/MachineFunction.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index b8dbe834a4d511..229b9adf4049fd 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -1053,7 +1053,7 @@ auto MachineFunction::salvageCopySSA(
   // Check whether this copy-like instruction has already been salvaged into
   // an operand pair.
   Register Dest;
-  if (auto CopyDstSrc = TII.isCopyInstr(MI)) {
+  if (auto CopyDstSrc = TII.isCopyLikeInstr(MI)) {
     Dest = CopyDstSrc->Destination->getReg();
   } else {
     assert(MI.isSubregToReg());
@@ -1137,7 +1137,7 @@ auto MachineFunction::salvageCopySSAImpl(MachineInstr &MI)
     CurInst = Inst.getIterator();
 
     // Any non-copy instruction is the defining instruction we're seeking.
-    if (!Inst.isCopyLike() && !TII.isCopyInstr(Inst))
+    if (!Inst.isCopyLike() && !TII.isCopyLikeInstr(Inst))
       break;
     State = GetRegAndSubreg(Inst);
   };