[IR] Do not set `none` for function uwtable (#93387)

This avoids the pitfall where we set the uwtable to none:
```
func.setUWTableKind(llvm::UWTableKind::None)
```
`Attribute::getAsString()` would see an unknown attribute and fail an
assertion. In this patch, we assert that we do not see a None uwtable
kind.

This also skips the check of `UWTableKind::Async`. It is dominated by
the check of `UWTableKind::Default`, which has the same enum value
(nfc).

1 files changed, 1 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/MachineOutliner.cpp b/llvm/lib/CodeGen/MachineOutliner.cpp
index dc2f5ef..f174dd8 100644
--- a/llvm/lib/CodeGen/MachineOutliner.cpp
+++ b/llvm/lib/CodeGen/MachineOutliner.cpp
@@ -717,8 +717,7 @@ MachineFunction *MachineOutliner::createOutlinedFunction(
       [](UWTableKind K, const outliner::Candidate &C) {
         return std::max(K, C.getMF()->getFunction().getUWTableKind());
       });
-  if (UW != UWTableKind::None)
-    F->setUWTableKind(UW);
+  F->setUWTableKind(UW);
 
   BasicBlock *EntryBB = BasicBlock::Create(C, "entry", F);
   IRBuilder<> Builder(EntryBB);