[clang] [clang][StaticAnalyzer] Fix crash in SimpleSValBuilder with unsigned __int128 and negative literals (PR #150225)

[Balazs Benics via cfe-commits]

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@@ -202,6 +213,11 @@ void BuiltinFunctionChecker::handleOverflowBuiltin(const CallEvent &Call,
   // Calling a builtin with an incorrect argument count produces compiler error.
   assert(Call.getNumArgs() == 3);
 
+  // If ResultType is null, we can't proceed with the evaluation
+  if (ResultType.isNull()) {
+    return;
+  }
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steakhal wrote:

When can `ResultType` be null? Is it that the `getSufficientTypeForOverflowOp` of `__int128` is a null QualType?

https://github.com/llvm/llvm-project/pull/150225