[llvm] AMDGPU: Fix -Wextra (PR #138539)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Matt Arsenault (arsenm)

<details>
<summary>Changes</summary>

Another stupid gcc warning. Ideally we would directly use the enum type,
but subregister indexes are emitted as an anonymous enum.

Fixes #<!-- -->125548

---
Full diff: https://github.com/llvm/llvm-project/pull/138539.diff


1 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp (+3-2) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
index 9c9b3d5d4f97f..ca7b737f4437c 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
@@ -2521,8 +2521,9 @@ bool AMDGPUInstructionSelector::selectG_TRUNC(MachineInstr &I) const {
     return false;
 
   if (SrcSize > 32) {
-    unsigned SubRegIdx =
-        DstSize < 32 ? AMDGPU::sub0 : TRI.getSubRegFromChannel(0, DstSize / 32);
+    unsigned SubRegIdx = DstSize < 32
+                             ? static_cast<unsigned>(AMDGPU::sub0)
+                             : TRI.getSubRegFromChannel(0, DstSize / 32);
     if (SubRegIdx == AMDGPU::NoSubRegister)
       return false;
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/138539