[llvm] [AMDGPU] si-peephole-sdwa: reuse getOne{NonDBGUse,Def} (NFC) (PR #156455)

[Frederik Harwath via llvm-commits]

https://github.com/frederik-h created https://github.com/llvm/llvm-project/pull/156455

None

>From 21860fab51e8b995c5228a2eca52c4ea44b05565 Mon Sep 17 00:00:00 2001
From: Frederik Harwath <fharwath at amd.com>
Date: Tue, 2 Sep 2025 06:37:32 -0400
Subject: [PATCH 1/3] Add MachineRegisterInfo::getOneNonDBGUse

This function is defined analogous to the existing getOneNonDBGUser.
---
 llvm/include/llvm/CodeGen/MachineRegisterInfo.h | 4 ++++
 llvm/lib/CodeGen/MachineRegisterInfo.cpp        | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/llvm/include/llvm/CodeGen/MachineRegisterInfo.h b/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
index e579dc53ab061..27b30bd5929ff 100644
--- a/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -579,6 +579,10 @@ class MachineRegisterInfo {
   /// multiple uses.
   LLVM_ABI bool hasOneNonDBGUser(Register RegNo) const;
 
+  /// If the register has a single non-Debug use, returns it; otherwise returns
+  /// nullptr.
+  LLVM_ABI MachineOperand *getOneNonDBGUse(Register RegNo) const;
+
   /// If the register has a single non-Debug instruction using the specified
   /// register, returns it; otherwise returns nullptr.
   LLVM_ABI MachineInstr *getOneNonDBGUser(Register RegNo) const;
diff --git a/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
index b7135251781ad..abb3f3e612000 100644
--- a/llvm/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
@@ -432,6 +432,11 @@ bool MachineRegisterInfo::hasOneNonDBGUser(Register RegNo) const {
   return hasSingleElement(use_nodbg_instructions(RegNo));
 }
 
+MachineOperand *MachineRegisterInfo::getOneNonDBGUse(Register RegNo) const {
+  auto RegNoDbgUses = use_nodbg_operands(RegNo);
+  return hasSingleElement(RegNoDbgUses) ? &*RegNoDbgUses.begin() : nullptr;
+}
+
 MachineInstr *MachineRegisterInfo::getOneNonDBGUser(Register RegNo) const {
   auto RegNoDbgUsers = use_nodbg_instructions(RegNo);
   return hasSingleElement(RegNoDbgUsers) ? &*RegNoDbgUsers.begin() : nullptr;

>From 20cb966a8451200b37ed94f31b4925f16480036f Mon Sep 17 00:00:00 2001
From: Frederik Harwath <fharwath at amd.com>
Date: Tue, 2 Sep 2025 06:38:27 -0400
Subject: [PATCH 2/3] [AMDGPU] si-peephole-sdwa: Use
 MachineRegisterInfo::getOneNonDBGUse

---
 llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp b/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
index d0cba30a442b4..b012fb33ceb4b 100644
--- a/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
+++ b/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
@@ -291,21 +291,7 @@ static MachineOperand *findSingleRegUse(const MachineOperand *Reg,
   if (!Reg->isReg() || !Reg->isDef())
     return nullptr;
 
-  MachineOperand *ResMO = nullptr;
-  for (MachineOperand &UseMO : MRI->use_nodbg_operands(Reg->getReg())) {
-    // If there exist use of subreg of Reg then return nullptr
-    if (!isSameReg(UseMO, *Reg))
-      return nullptr;
-
-    // Check that there is only one instruction that uses Reg
-    if (!ResMO) {
-      ResMO = &UseMO;
-    } else if (ResMO->getParent() != UseMO.getParent()) {
-      return nullptr;
-    }
-  }
-
-  return ResMO;
+  return MRI->getOneNonDBGUse(Reg->getReg());
 }
 
 static MachineOperand *findSingleRegDef(const MachineOperand *Reg,

>From 12d1cdc51cd81e6404b0ca668559800323ed2cfd Mon Sep 17 00:00:00 2001
From: Frederik Harwath <fharwath at amd.com>
Date: Tue, 2 Sep 2025 09:05:26 -0400
Subject: [PATCH 3/3] [AMDGPU] si-peephole-sdwa: Use
 MachineRegisterinfo::getOneDef for findSingleRegDef

---
 llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp b/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
index b012fb33ceb4b..857cb91a977f3 100644
--- a/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
+++ b/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
@@ -299,17 +299,7 @@ static MachineOperand *findSingleRegDef(const MachineOperand *Reg,
   if (!Reg->isReg())
     return nullptr;
 
-  MachineInstr *DefInstr = MRI->getUniqueVRegDef(Reg->getReg());
-  if (!DefInstr)
-    return nullptr;
-
-  for (auto &DefMO : DefInstr->defs()) {
-    if (DefMO.isReg() && DefMO.getReg() == Reg->getReg())
-      return &DefMO;
-  }
-
-  // Ignore implicit defs.
-  return nullptr;
+  return MRI->getOneDef(Reg->getReg());
 }
 
 /// Combine an SDWA instruction's existing SDWA selection \p Sel with