[llvm] [AMDGPU] Use unsigned overflow for S_UADDO_PSEUDO/S_USUBO_PSEUDO (PR #160142)

[via llvm-commits]

https://github.com/LU-JOHN created https://github.com/llvm/llvm-project/pull/160142

Use correct unsigned overflow instructions for S_UADDO_PSEUDO/S_USUBO_PSEUDO.  Note that this issue was hidden because instruction selection never selected S_UADDO_PSEUDO/S_USUBO_PSEUDO which will be addressed in https://github.com/llvm/llvm-project/pull/159814.

>From 0433ac3d0e142470a46505894a8f5a180d6a50c8 Mon Sep 17 00:00:00 2001
From: John Lu <John.Lu at amd.com>
Date: Mon, 22 Sep 2025 11:18:58 -0500
Subject: [PATCH] Use unsigned overflow

Signed-off-by: John Lu <John.Lu at amd.com>
---
 llvm/lib/Target/AMDGPU/SIISelLowering.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index 78d608556f056..febcd304c9ef4 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -5953,8 +5953,8 @@ SITargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
     MachineOperand &Src1 = MI.getOperand(3);
 
     unsigned Opc = (MI.getOpcode() == AMDGPU::S_UADDO_PSEUDO)
-                       ? AMDGPU::S_ADD_I32
-                       : AMDGPU::S_SUB_I32;
+                       ? AMDGPU::S_ADD_U32
+                       : AMDGPU::S_SUB_U32;
     // clang-format off
     BuildMI(*BB, MI, DL, TII->get(Opc), Dest0.getReg())
         .add(Src0)