[llvm] [llvm] Bail out when meeting pointer with negative offset instead of … (PR #120424)

[via llvm-commits]

================
@@ -841,8 +841,7 @@ OffsetSpan ObjectSizeOffsetVisitor::computeImpl(Value *V) {
     // This is UB, and we'd rather return an empty location then.
     if (Options.EvalMode == ObjectSizeOpts::Mode::Min ||
         Options.EvalMode == ObjectSizeOpts::Mode::Max) {
-      ORT.Before = APInt::getZero(ORT.Before.getBitWidth());
-      ORT.After = APInt::getZero(ORT.Before.getBitWidth());
+      return ObjectSizeOffsetVisitor::unknown();
----------------
serge-sans-paille wrote:

Not at all, i'll update it. The idea would be 'if we are uncertain about the accuracy and the validity of the access, better be safe and bail out rather than return a potentially invalid result.

https://github.com/llvm/llvm-project/pull/120424