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

[via llvm-commits]

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@@ -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)
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hiraditya wrote:

Is `sizeof(int)` guaranteed to be same across all platforms? Maybe we should hardcode what we want.

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