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Author: kasuga-fj

llvm/lib/Analysis/DependenceAnalysis.cpp

@@ -3786,6 +3786,23 @@ bool DependenceInfo::tryDelinearizeParametricSize(
       return false;
     }
 
+  // TODO: Probably we need to prove that the "offset calculation" doesn't
+  // wrap. Here the offset calculation is:
+  //
+  //   Offset =
+  //     Subscripts[0] +
+  //     Subscripts[1]*Sizes[0] +
+  //     Subscripts[2]*Sizes[0]*Sizes[1] +
+  //     ...
+  //     Subscripts[N-1]*Sizes[0]*Sizes[1]*...*Sizes[N-2]
+  //
+  // where `N` is the number of dimensions. The subsequent dependence tests
+  // assume that different subscript values result in different offset values.
+  // If the above calculation wraps, this assumption is violated.
+  // Note that if every element of Subscripts is positive, the situation would
+  // be simple. However, the subscript for the outermost dimension
+  // (Subscripts[0]) can be negative.
+
   return true;
 }