From 91b2e5bc5d3bcad511f3dfd90e1cedf796218675 Mon Sep 17 00:00:00 2001
From: Jake Daly <48452250+jakemdaly@users.noreply.github.com>
Date: Wed, 21 May 2025 09:25:25 -0700
Subject: [PATCH] Add live in for PrivateSegmentSize in GISel path (#139968)

---
 llvm/lib/Target/AMDGPU/AMDGPUCallLowering.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUCallLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUCallLowering.cpp
index e977b9069173..98a32f9225ba 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUCallLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUCallLowering.cpp
@@ -493,6 +493,12 @@ static void allocateHSAUserSGPRs(CCState &CCInfo,
     CCInfo.AllocateReg(FlatScratchInitReg);
   }
 
+  if (UserSGPRInfo.hasPrivateSegmentSize()) {
+    Register PrivateSegmentSizeReg = Info.addPrivateSegmentSize(TRI);
+    MF.addLiveIn(PrivateSegmentSizeReg, &AMDGPU::SGPR_32RegClass);
+    CCInfo.AllocateReg(PrivateSegmentSizeReg);
+  }
+
   // TODO: Add GridWorkGroupCount user SGPRs when used. For now with HSA we read
   // these from the dispatch pointer.
 }