[llvm] [msan] Assume noundef for sret parameters under eager checks (PR #224346)

[Vitaly Buka via llvm-commits]

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@@ -2146,8 +2146,10 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
             }
           }
 
+          bool NoUndef =
+              FArg.hasAttribute(Attribute::NoUndef) || FArg.hasStructRetAttr();
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vitalybuka wrote:

Actually @nikic suggests the opposite :)
https://github.com/rust-lang/rust/issues/162902#issuecomment-5716052635

I don't have strong preference.

https://github.com/llvm/llvm-project/pull/224346