[llvm] [LAA] Fix off-by-EltSize in negative-step deref bounds check (PR #211964)

[Aleksandr Popov via llvm-commits]

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@@ -206,6 +206,16 @@ static const SCEV *mulSCEVNoOverflow(const SCEV *A, const SCEV *B,
 
 /// Return true, if evaluating \p AR at \p MaxBTC cannot wrap, because \p AR at
 /// \p MaxBTC is guaranteed inbounds of the accessed object.
+///
+/// The accessed byte range is [LowestOffset, LowestOffset + AccessedBytes),
+/// where
+///   AccessedBytes = MaxBTC * |Step| + EltSize,
+///   LowestOffset  = smallest byte offset from StartPtr any iteration reaches.
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aleks-tmb wrote:

Done

https://github.com/llvm/llvm-project/pull/211964