[Mlir-commits] [mlir] [MLIR][Presburger] Implement Matrix::moveColumns (PR #68362)

[Bharathi Ramana Joshi]

https://github.com/iambrj created https://github.com/llvm/llvm-project/pull/68362

None

>From d38897639f3d5d30504a1dcf729a9099462ee284 Mon Sep 17 00:00:00 2001
From: iambrj <joshibharathiramana at gmail.com>
Date: Fri, 6 Oct 2023 02:09:58 +0400
Subject: [PATCH] [MLIR][Presburger] Implement Matrix::moveColumns

---
 .../include/mlir/Analysis/Presburger/Matrix.h | 17 ++++++
 mlir/lib/Analysis/Presburger/Matrix.cpp       | 26 +++++++-
 .../Analysis/Presburger/MatrixTest.cpp        | 59 ++++++++++++++++++-
 3 files changed, 98 insertions(+), 4 deletions(-)

diff --git a/mlir/include/mlir/Analysis/Presburger/Matrix.h b/mlir/include/mlir/Analysis/Presburger/Matrix.h
index bed3a5f75e396c5..0325d5ebd017bbe 100644
--- a/mlir/include/mlir/Analysis/Presburger/Matrix.h
+++ b/mlir/include/mlir/Analysis/Presburger/Matrix.h
@@ -189,6 +189,23 @@ static_assert(std::is_same_v<T,MPInt> || std::is_same_v<T,Fraction>, "T must be
   /// invariants satisfied.
   bool hasConsistentState() const;
 
+  /// Shift the columns in the range [srcPos, srcPos + num] by the specified
+  /// offset, i.e. to [srcPos + offset, srcPos + num + offset], while moving
+  /// the columns adjacent to the range to the left/right of the shifted
+  /// columns.
+  ///
+  /// For a positive offset (i.e. shifting the columns right), columns that
+  /// were at positions [0, srcPos) will stay where they are; columns that were
+  /// at positions [srcPos + num, srcPos + num + offset) will be moved to
+  /// [srcPos, srcPos + offset); and columns that were at positions
+  /// (src + num + offset, nCols) will remain where they were. For example,
+  /// if m = |0 1 2 3 4 5| then m.moveColumns(1, 2, 3) will result in
+  /// m = |0 3 4 5 1 2|.
+  ///
+  /// Similarly, a negative offset results in a left shift of the columns in
+  /// the range [srcPos, srcPos + num].
+  void moveColumns(unsigned srcPos, unsigned num, int offset);
+
 private:
   /// The current number of rows, columns, and reserved columns. The underlying
   /// data vector is viewed as an nRows x nReservedColumns matrix, of which the
diff --git a/mlir/lib/Analysis/Presburger/Matrix.cpp b/mlir/lib/Analysis/Presburger/Matrix.cpp
index f0bcb09fb28f7b1..4c8d63055fc5eb3 100644
--- a/mlir/lib/Analysis/Presburger/Matrix.cpp
+++ b/mlir/lib/Analysis/Presburger/Matrix.cpp
@@ -192,6 +192,30 @@ template <typename T> void Matrix<T>::fillRow(unsigned row, const T &value) {
     at(row, col) = value;
 }
 
+template <typename T> void Matrix<T>::moveColumns(unsigned srcPos, unsigned num, int offset) {
+  assert(num != 0 && "num must be non-zero");
+  assert(offset != 0 && "offset must be non-zero");
+  assert(0 <= srcPos + offset && srcPos + num + offset <= getNumColumns() &&
+      "invalid move offset");
+
+  unsigned insertCount = offset > 0 ? offset : -offset,
+           insertPos = offset > 0 ? srcPos : srcPos + num,
+           deletePos = offset > 0 ? srcPos + num : srcPos + offset;
+  // Insert new zero columns in the positions where the adjacent columns are to
+  // be moved.
+  insertColumns(insertPos, insertCount);
+  // Update deletePos if insertion of new columns invalidates it.
+  if(insertPos < deletePos)
+    deletePos += insertCount;
+
+  // Swap the adjacent columns with inserted zero columns.
+  for(unsigned i = 0; i < insertCount; i++)
+    swapColumns(insertPos + i, deletePos + i);
+
+  // Delete the now redundant zero columns.
+  removeColumns(deletePos, insertCount);
+}
+
 template <typename T> void Matrix<T>::addToRow(unsigned sourceRow, unsigned targetRow,
                       const T &scale) {
   addToRow(targetRow, getRow(sourceRow), scale);
@@ -390,4 +414,4 @@ MPInt IntMatrix::normalizeRow(unsigned row, unsigned cols) {
 
 MPInt IntMatrix::normalizeRow(unsigned row) {
   return normalizeRow(row, getNumColumns());
-}
\ No newline at end of file
+}
diff --git a/mlir/unittests/Analysis/Presburger/MatrixTest.cpp b/mlir/unittests/Analysis/Presburger/MatrixTest.cpp
index 6b23cedabf624ec..57e0fe627bec5af 100644
--- a/mlir/unittests/Analysis/Presburger/MatrixTest.cpp
+++ b/mlir/unittests/Analysis/Presburger/MatrixTest.cpp
@@ -194,13 +194,21 @@ TEST(MatrixTest, resize) {
       EXPECT_EQ(mat(row, col), row >= 3 || col >= 3 ? 0 : int(10 * row + col));
 }
 
+template <typename T>
+static void checkMatEqual(const Matrix<T> m1, const Matrix<T> m2) {
+  EXPECT_EQ(m1.getNumRows(), m2.getNumRows());
+  EXPECT_EQ(m1.getNumColumns(), m2.getNumColumns());
+
+  for (unsigned row = 0; row < m1.getNumRows(); row++)
+    for (unsigned col = 0; col < m2.getNumColumns(); col++)
+      EXPECT_EQ(m1(row, col), m2(row, col));
+}
+
 static void checkHermiteNormalForm(const IntMatrix &mat,
                                    const IntMatrix &hermiteForm) {
   auto [h, u] = mat.computeHermiteNormalForm();
 
-  for (unsigned row = 0; row < mat.getNumRows(); row++)
-    for (unsigned col = 0; col < mat.getNumColumns(); col++)
-      EXPECT_EQ(h(row, col), hermiteForm(row, col));
+  checkMatEqual(h, hermiteForm);
 }
 
 TEST(MatrixTest, computeHermiteNormalForm) {
@@ -248,3 +256,48 @@ TEST(MatrixTest, computeHermiteNormalForm) {
     checkHermiteNormalForm(mat, hermiteForm);
   }
 }
+
+TEST(MatrixTest, moveColumns) {
+  IntMatrix mat = makeIntMatrix(3, 4,
+      {{0, 1, 2, 3},
+       {4, 5, 6, 7},
+       {8, 9, 4, 2}});
+
+  {
+    IntMatrix movedMat = makeIntMatrix(3, 4,
+      {{0, 3, 1, 2},
+       {4, 7, 5, 6},
+       {8, 2, 9, 4}});
+
+    movedMat.moveColumns(2, 2, -1);
+    checkMatEqual(mat, movedMat);
+  }
+
+  {
+    IntMatrix movedMat = makeIntMatrix(3, 4,
+      {{0, 3, 1, 2},
+       {4, 7, 5, 6},
+       {8, 2, 9, 4}});
+
+    movedMat.moveColumns(1, 1, 2);
+    checkMatEqual(mat, movedMat);
+  }
+
+  {
+    IntMatrix movedMat = makeIntMatrix(3, 4,
+      {{1, 2, 0, 3},
+       {5, 6, 4, 7},
+       {9, 4, 8, 2}});
+
+    movedMat.moveColumns(0, 2, 1);
+    checkMatEqual(mat, movedMat);
+  }
+
+  {
+    IntMatrix movedMat =
+        makeIntMatrix(3, 4, {{1, 0, 2, 3}, {5, 4, 6, 7}, {9, 8, 4, 2}});
+
+    movedMat.moveColumns(0, 1, 1);
+    checkMatEqual(mat, movedMat);
+  }
+}