[clang] [clang][CodeGen] Ensure consistent `mustprogress` attribute emission across all paths (PR #71452)

[Eli Friedman via cfe-commits]

================
@@ -1482,6 +1477,11 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
   } else
     llvm_unreachable("no definition for emitted function");
 
+  // This is checked after emitting the function body so we know if there
+  // are any permitted infinite loops.
----------------
efriedma-quic wrote:

Fundamentally, I'm not sure there's any reason we need to do this after emitting the function body.  When the comment was written, it was referring to the FnIsMustProgress bit in CodeGenFunction, but that was removed.

https://github.com/llvm/llvm-project/pull/71452