[polly] r259633 - ScopInfo: Extend description of the access relation.

Tobias Grosser via llvm-commits llvm-commits at lists.llvm.org
Tue Feb 2 22:37:39 PST 2016


Author: grosser
Date: Wed Feb  3 00:37:38 2016
New Revision: 259633

URL: http://llvm.org/viewvc/llvm-project?rev=259633&view=rev
Log:
ScopInfo: Extend description of the access relation.

Modified:
    polly/trunk/include/polly/ScopInfo.h

Modified: polly/trunk/include/polly/ScopInfo.h
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/include/polly/ScopInfo.h?rev=259633&r1=259632&r2=259633&view=diff
==============================================================================
--- polly/trunk/include/polly/ScopInfo.h (original)
+++ polly/trunk/include/polly/ScopInfo.h Wed Feb  3 00:37:38 2016
@@ -524,7 +524,22 @@ private:
   /// @brief Subscript expression for each dimension.
   SmallVector<const SCEV *, 4> Subscripts;
 
-  /// @brief Relation from statment instances to the accessed array elements.
+  /// @brief Relation from statement instances to the accessed array elements.
+  ///
+  /// In the common case this relation is a function that maps a set of loop
+  /// indices to the memory address from which a value is loaded/stored.
+  ///
+  /// For example:
+  ///
+  ///      for i
+  ///        for j
+  ///    S:     A[i + 3 j] = ...
+  ///
+  ///    => { S[i,j] -> A[i + 3j] }
+  ///
+  /// In case the exact access function is not known, the access relation may
+  /// also be a one to all mapping { S[i,j] -> A[o] } describing that any
+  /// element accessible through A might be accessed.
   isl_map *AccessRelation;
 
   /// @brief Updated access relation read from JSCOP file.




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