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

[Eli Friedman via cfe-commits]

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@@ -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.
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efriedma-quic wrote:

No, I mean, there isn't a reason to specifically do it *after* emitting the function body, as opposed to before we emit it (when we compute most other attributes).

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