[Mlir-commits] [mlir] [MLIR][Presburger] optimize bound computation by pruning orthogonal constraints (PR #164199)

[Arjun P]

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@@ -511,6 +511,31 @@ class IntegerRelation {
   void projectOut(unsigned pos, unsigned num);
   inline void projectOut(unsigned pos) { return projectOut(pos, 1); }
 
+  /// The set of constraints (equations/inequalities) can be modeled as an
+  /// undirected graph where:
+  /// 1. Variables are the nodes.
+  /// 2. Constraints are the edges connecting those nodes.
+  ///
+  /// Variables and constraints belonging to different connected components
+  /// are irrelevant to each other. This property allows for safe pruning of
+  /// constraints.
+  ///
+  /// For example, given the following constraints:
+  /// - Inequalities: (1) d0 + d1 > 0, (2) d1 >= 2, (3) d4 > 5
+  /// - Equalities:   (4) d3 + d4 = 1, (5) d0 - d2 = 3
+  ///
+  /// These form two connected components:
+  /// - Component 1: {d0, d1, d2} (related by constraints 1, 2, 5)
+  /// - Component 2: {d3, d4} (related by constraint 4)
+  ///
+  /// If we are querying the bound of variable `d0`, constraints related to
+  /// Component 2 (e.g., constraints 3 and 4) can be safely pruned as they
+  /// have no impact on the solution space of Component 1.
+  /// This function prunes irrelevant constraints by identifying all variables
+  /// and constraints that belong to the same connected component as the
+  /// target variable.
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Superty wrote:

Can we change the name to `pruneOrthogonalConstraints` or something? I think that makes it more specific what's going on. We can also change the parameter name `pos` to `var` or something to make it clearer what it's supposed to be.

https://github.com/llvm/llvm-project/pull/164199