[llvm] [LAA] Fix implicit trunc from int64 to int and losing info (PR #139553)

[Ramkumar Ramachandra via llvm-commits]

================
@@ -1585,6 +1585,8 @@ std::optional<int> llvm::getPointersDiff(Type *ElemTyA, Value *PtrA,
     OffsetB = OffsetB.sextOrTrunc(IdxWidth);
 
     OffsetB -= OffsetA;
+    if (OffsetB.getSignificantBits() > sizeof(int) * 8)
+      return std::nullopt;
     Val = OffsetB.getSExtValue();
----------------
artagnon wrote:

> Sure, but just like for APInt, need to adjust all the users of this function to handle int64_t instead of int

Sounds like that is the right solution? `sizeof(int) * CHAR_BIT` doesn't seem like a good solution.

https://github.com/llvm/llvm-project/pull/139553