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

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: None (LU-JOHN)

<details>
<summary>Changes</summary>

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.

---
Full diff: https://github.com/llvm/llvm-project/pull/160142.diff


1 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/SIISelLowering.cpp (+2-2) 


``````````diff
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)

``````````

</details>


https://github.com/llvm/llvm-project/pull/160142