[llvm-branch-commits] [llvm] CodeGen: Stop checking for physregs in constrainRegClass (PR #161795)

[Matt Arsenault via llvm-branch-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/161795

It's nonsensical to call this function on a physical register.

>From 2833da98821c20e651468e63ef834acfa66cac88 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Fri, 3 Oct 2025 14:00:55 +0900
Subject: [PATCH] CodeGen: Stop checking for physregs in constrainRegClass

It's nonsensical to call this function on a physical register.
---
 llvm/lib/CodeGen/MachineRegisterInfo.cpp | 2 --
 1 file changed, 2 deletions(-)

diff --git a/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
index abb3f3e612000..ae284f3ae2929 100644
--- a/llvm/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
@@ -83,8 +83,6 @@ constrainRegClass(MachineRegisterInfo &MRI, Register Reg,
 
 const TargetRegisterClass *MachineRegisterInfo::constrainRegClass(
     Register Reg, const TargetRegisterClass *RC, unsigned MinNumRegs) {
-  if (Reg.isPhysical())
-    return nullptr;
   return ::constrainRegClass(*this, Reg, getRegClass(Reg), RC, MinNumRegs);
 }