[Mlir-commits] [mlir] fb857de - [MLIR][Presburger] Add inverse to IntegerRelation

[llvmlistbot at llvm.org]

Author: Groverkss
Date: 2022-05-25T19:37:52+05:30
New Revision: fb857ded70e108afec4f4f7e024b0315bbe00de4

URL: https://github.com/llvm/llvm-project/commit/fb857ded70e108afec4f4f7e024b0315bbe00de4
DIFF: https://github.com/llvm/llvm-project/commit/fb857ded70e108afec4f4f7e024b0315bbe00de4.diff

LOG: [MLIR][Presburger] Add inverse to IntegerRelation

This patch adds support for obtaining inverse of a relation.

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D126327

Added: 
    

Modified: 
    mlir/include/mlir/Analysis/Presburger/IntegerRelation.h
    mlir/lib/Analysis/Presburger/IntegerRelation.cpp
    mlir/unittests/Analysis/Presburger/IntegerRelationTest.cpp

Removed: 
    


################################################################################
diff  --git a/mlir/include/mlir/Analysis/Presburger/IntegerRelation.h b/mlir/include/mlir/Analysis/Presburger/IntegerRelation.h
index 1eca9efd39fb..b74413b9ff01 100644
--- a/mlir/include/mlir/Analysis/Presburger/IntegerRelation.h
+++ b/mlir/include/mlir/Analysis/Presburger/IntegerRelation.h
@@ -505,6 +505,12 @@ class IntegerRelation {
   /// Return a set corresponding to all points in the range of the relation.
   IntegerPolyhedron getRangeSet() const;
 
+  /// Invert the relation i.e., swap it's domain and range.
+  ///
+  /// Formally, let the relation `this` be R: A -> B, then this operation
+  /// modifies R to be B -> A.
+  void inverse();
+
   void print(raw_ostream &os) const;
   void dump() const;
 

diff  --git a/mlir/lib/Analysis/Presburger/IntegerRelation.cpp b/mlir/lib/Analysis/Presburger/IntegerRelation.cpp
index 4df84aaad906..87132728103a 100644
--- a/mlir/lib/Analysis/Presburger/IntegerRelation.cpp
+++ b/mlir/lib/Analysis/Presburger/IntegerRelation.cpp
@@ -2102,6 +2102,12 @@ IntegerPolyhedron IntegerRelation::getRangeSet() const {
   return IntegerPolyhedron(std::move(copyRel));
 }
 
+void IntegerRelation::inverse() {
+  unsigned numRangeIds = getNumIdKind(IdKind::Range);
+  convertIdKind(IdKind::Domain, 0, getIdKindEnd(IdKind::Domain), IdKind::Range);
+  convertIdKind(IdKind::Range, 0, numRangeIds, IdKind::Domain);
+}
+
 void IntegerRelation::printSpace(raw_ostream &os) const {
   space.print(os);
   os << getNumConstraints() << " constraints\n";

diff  --git a/mlir/unittests/Analysis/Presburger/IntegerRelationTest.cpp b/mlir/unittests/Analysis/Presburger/IntegerRelationTest.cpp
index 06dbee01896b..ee922584f564 100644
--- a/mlir/unittests/Analysis/Presburger/IntegerRelationTest.cpp
+++ b/mlir/unittests/Analysis/Presburger/IntegerRelationTest.cpp
@@ -41,3 +41,19 @@ TEST(IntegerRelationTest, getDomainAndRangeSet) {
 
   EXPECT_TRUE(rangeSet.isEqual(expectedRangeSet));
 }
+
+TEST(IntegerRelationTest, inverse) {
+  IntegerRelation rel =
+      parseRelationFromSet("(x, y, z)[N, M] : (z - x - y == 0, x >= 0, N - x "
+                           ">= 0, y >= 0, M - y >= 0)",
+                           2);
+
+  IntegerRelation inverseRel =
+      parseRelationFromSet("(z, x, y)[N, M]  : (x >= 0, N - x >= 0, y >= 0, M "
+                           "- y >= 0, x + y - z == 0)",
+                           1);
+
+  rel.inverse();
+
+  EXPECT_TRUE(rel.isEqual(inverseRel));
+}