[llvm] [llvm] Fix behavior of llvm.objectsize in presence of negative / large offset (PR #115504)

[via llvm-commits]

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@@ -580,6 +585,11 @@ bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL,
   if (!Data.bothKnown())
     return false;
 
+  // We could compute an over-approximation in that situation, may be if
+  // Opts.EvalMode == Max, but let's bee conservative and bail out.
+  if (Data.Offset.isNegative())
+    return false;
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serge-sans-paille wrote:

I tend to agree. Let's explore that in another PR though, this one already looks like a nice step forward and I'm not eager to see it grow beyond its state.

https://github.com/llvm/llvm-project/pull/115504