[llvm] MachineFunction: Remove null check on TargetRegisterInfo (PR #128480)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/128480

Targets are required to define this, it is not optional. Make the method
pure virtual to enforce this

>From 8177ae4ed110490c62251409ecb77912a606e14c Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 24 Feb 2025 15:25:03 +0700
Subject: [PATCH] MachineFunction: Remove null check on TargetRegisterInfo

Targets are required to define this, it is not optional. Make the method
pure virtual to enforce this
---
 llvm/include/llvm/CodeGen/TargetSubtargetInfo.h | 5 ++---
 llvm/lib/CodeGen/MachineFunction.cpp            | 5 +----
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/TargetSubtargetInfo.h b/llvm/include/llvm/CodeGen/TargetSubtargetInfo.h
index 76c94981e1afc..1230349956973 100644
--- a/llvm/include/llvm/CodeGen/TargetSubtargetInfo.h
+++ b/llvm/include/llvm/CodeGen/TargetSubtargetInfo.h
@@ -124,9 +124,8 @@ class TargetSubtargetInfo : public MCSubtargetInfo {
 
   virtual const LegalizerInfo *getLegalizerInfo() const { return nullptr; }
 
-  /// getRegisterInfo - If register information is available, return it.  If
-  /// not, return null.
-  virtual const TargetRegisterInfo *getRegisterInfo() const { return nullptr; }
+  /// Return the target's register information.
+  virtual const TargetRegisterInfo *getRegisterInfo() const = 0;
 
   /// If the information for the register banks is available, return it.
   /// Otherwise return nullptr.
diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index 6e0342a763d15..eb0a16732b058 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -189,10 +189,7 @@ void MachineFunction::init() {
   // Assume the function starts in SSA form with correct liveness.
   Properties.set(MachineFunctionProperties::Property::IsSSA);
   Properties.set(MachineFunctionProperties::Property::TracksLiveness);
-  if (STI->getRegisterInfo())
-    RegInfo = new (Allocator) MachineRegisterInfo(this);
-  else
-    RegInfo = nullptr;
+  RegInfo = new (Allocator) MachineRegisterInfo(this);
 
   MFInfo = nullptr;